EP0240493B1 - Method for compaction-trussing-injection or decompaction-draining and construction of linear works or planar works in grounds - Google Patents

Abstract

PCT No. PCT/FR85/00337 Sec. 371 Date Aug. 7, 1986 Sec. 102(e) Date Aug. 7, 1986 PCT Filed Nov. 27, 1985 PCT Pub. No. WO86/03533 PCT Pub. Date Jun. 19, 1986.Process for soil treatment and successive installations of a plurality of equipments at different respective locations and apparatus for implementing said process, comprising the operations of: drilling the soil by driving a tubular stem tool having an axis and a predetermined overall diameter around its axis, introducing one equipment inside the tubular stem tool, removing from the soil said tubular stem tool while leaving the equipment within the soil, modifying the soil compacity around the equipment by mechanical action during at least part of the removal of the tubular stem tool and repeating the above operations with remaining equipments at other locations.

Description

• 1. Pour le traitement de masse d'un sol, soit par armature-injection- compactage, soit par décompactage-drainage, soit par une combinaison de ces deux effets.
• 2. Pour la construction d'ouvrages linéaires dans le sol enrobés de terrain compacté ou de terrain décompacté.
• 3. Pour la construction d'ouvrages plans dans le sol en terrain armé-injecté-compacté, ou en terrain décompacté-drainé, ou en une combinaison de ces deux types de traitement.

The present invention relates to a method serving:

• 1. For the mass treatment of a soil, either by reinforcement-injection-compaction, or by unpacking-drainage, or by a combination of these two effects.
• 2. For the construction of linear structures in the soil coated with compacted or uncompacted soil.
• 3. For the construction of flat structures in the soil in reinforced-injected-compacted soil, or in uncompacted-drained soil, or in a combination of these two types of treatment.

By linear work in the ground is meant any civil engineering work constructed deep in the ground from the surface thereof or from the edges or bottom of an excavation and one of whose dimensions, in the sense of depth, is significantly larger than the other two.

By planar structure in the ground is meant any structure involving a continuous mass of soil forming a volume, one of the dimensions of which is smaller than the other two.

A. Technical area to which the process relates

The method relates to the field of ground treatment, either for the foundation of structures on these grounds, or for their stability or their waterproofing, and to the field of construction of linear structures deep in the ground for which it is necessary or useful to obtain the compaction (or the decompaction) of the grounds which surround them. These linear structures can be, for example, piles or micropiles, drains, water boreholes, anchor rods, special tubes for injection, or measuring devices such as piezometers, inclinometers, measuring cells, etc. They may or may not include metallic elements coated or not with filler materials or else simply consist of added materials. It also applies to the case of flat structures in the ground, such as for example the treatment of the edge and bottom of excavations, retaining walls in compacted, injected and reinforced soil, sealing walls and draining walls in the soil, or their combination in the form of bi-layer, multi-layer or composite walls, waterproof, draining or composite rafts (bi-layer or multi-layer), etc.

The process makes it possible to obtain, using a single tool, lowered only once into the ground, either mechanically compacted soil, treated by injection and reinforced, or loosened soil equipped with drains, or an isolated linear structure surrounded by compacted or uncompacted soil.

B. State of the art

In the current state of the art, there are many methods of mechanical compaction, treatment by injection and introduction of reinforcements into the soil with a view to modifying their mechanical qualities and / or impermeability. There are also many methods of drainage and installation of piles, tie rods and measuring devices in the ground, at various depths, among which is the process which is the subject of document DE-A-2431113 .

In general, the processes in question relate either to the treatment of the soil itself, generally by compaction or injection, or to the installation of a structure in it. In the second case, the installation of the structure can be accompanied or followed by a treatment of the surrounding ground, for example by injection.

The existing methods do not make it possible to carry out all the desirable or useful operations at the same time, on the one hand for the installation of the structure in the ground, on the other hand for the compaction and the treatment of the surrounding ground . It is thus often necessary, either to use two successive operations to obtain the desired result (for example: placement of micropiles, then injection of the soil around their base to ensure the compacting of the anchoring zone), or be limited to a single operation (for example: simple soil compaction, without the introduction of reinforcement).

C. Characteristics of the Process

• ce procédé étant caractérisé en ce qu'il comprend en outre les étapes supplémentaires consistant à:
• introduire l'un de ces équipements à l'intérieur de l'outil à âme tubulaire en le faisant descendre jusqu'à une position prédéterminée pour ledit équipement par rapport au terrain,
• retirer du terrain l'outil à âme tubulaire tout en laissant ledit équipement à l'intérieur du terrain dans sa position prédéterminée,
• modifier la compacité du terrain dans au moins une partie du volume correspondant au diamètre extérieur de l'outil autour dudit équipement par une action mécanique, durant au moins une partie du retrait de l'outil à âme tubulaire, et
• répéter les étapes ci-dessus avec chacun des autres équipements en chacun des autres emplacements respectifs.

According to a first of its aspects, the invention provides a method for the treatment of land and the successive installation of several pieces of equipment at respective locations different from this land, method according to which one begins by drilling the land at one of said locations by driving, in this terrain, a tool with a tubular core having a tube forming its core and parts fixed on this tube defining an outside diameter of the tool;

• this process being characterized in that it further comprises the additional steps consisting in:
• introduce one of these pieces of equipment inside the tubular core tool by lowering it to a predetermined position for said piece of equipment with respect to the ground,
• remove the tubular core tool from the ground while leaving said equipment inside the ground in its predetermined position,
• modifying the compactness of the ground in at least part of the volume corresponding to the outside diameter of the tool around said equipment by mechanical action, during at least part of the withdrawal of the tool with tubular core, and
• repeat the above steps with each of the other equipment at each of the other respective locations.

• la modification de la compacité du terrain est réalisée avec ledit outil à âme tubulaire;
• l'outil à âme tubulaire étant constitué d'une tarière hélicoïdale creuse, le procédé comprend les étapes consistant à:
• introduire cette tarière hélicoïdale dans le terrain par un vissage de ladite tarière dans le terrain, introduire l'équipement par l'intérieur de l'âme creuse de la tarière et
• retirer cette tarière du terrain par un dévissage de ladite tarière tout en imprimant à cette dernière, pour chaque tour de rotation, un déplacement axial différent de son pas d'hélice, ce grâce à quoi on modifie la compacité du terrain autour dudit équipement;
• l'outil à âme tubulaire est soumis à des vibrations lorsqu'il est retiré du terrain, ce grâce à quoi on augmente la compacité du terrain autour dudit équipement;
• ledit équipement est soumis à des vibrations au cours du retrait de l'outil à âme tubulaire hors du terrain, ce grâce à quoi on augmente la compacité du terrain autour de l'équipement;
• le procédé comprend, en outre, l'étape consistant à introduire un matériau d'apport autour dudit équipement tandis que l'on retire l'outil à âme tubulaire, de manière à constituer une gaine en matériau d'apport autour dudit équipement;
• le procédé comprend en outre l'étape consistant à effectuer une injection sous pression du terrain autour dudit équipement tandis que l'on retire l'outil à âme tubulaire en pompant un matériau liquide durcissant tel qu'un coulis de ciment ou un coulis chimique dans le terrain autour dudit équipement;
• l'outil à âme tubulaire étant constitué par une tarière hélicoïdale creuse, le procédé comprend en outre, au cours du retrait de cette tarière hélicoïdale, les étapes consistant à:
• créer au moins un espace creux élargi dans le terrain autour dudit équipement en remontant la tarière hélicoïdale d'une distance prédéterminée et
• introduire un matériau d'apport au niveau du bas de la tarière hélicoïdale pour remplir le susdit espace creux élargi et pour établir une zone élargie ou bulbe en matériau d'apport autour dudit équipement;
• un matériau d'apport est introduit par l'espace existant entre la face intérieure du tube constituant l'âme de l'outil à âme tubulaire et ledit équipement tandis que l'on retire l'outil à âme tubulaire;
• le forage du terrain par entraînement d'un outil à âme tubulaire dans ce dernier comporte en outre les étapes consistant à:
• introduire un train de tiges muni d'un outil de forage à l'intérieur de l'outil à âme tubulaire pour forer une couche dure dans le terrain ou une roche sousjacente à l'aide d'une tête d'entraînement auxiliaire agissant sur ledit train de tiges,
• retirer ce train de tiges et l'outil de forage hors de l'outil à âme tubulaire avant d'introduire ledit équipement et de réaliser les autres étapes;
• après le forage du terrain par entraînement de l'outil à âme tubulaire dans ce dernier, le procédé comprend les étapes consistant à:
• introduire un équipement muni d'un outil de forage dans l'outil à âme tubulaire en le faisant descendre jusqu'au bas de l'outil à âme tubulaire et
• faire tourner ledit équipement à l'aide d'une tête d'entraînement auxiliaire pour forer une couche dure dans le terrain ou une roche sous- jacente avec l'outil de forage avant de retirer du terrain l'outil à âme tubulaire tout en laissant ledit équipement et son outil de forage dans le terrain;
• après avoir introduit ledit équipement à l'intérieur de l'outil à âme tubulaire, le procédé comprend les étapes consistant à:
• connecter un train de tiges au haut dudit équipement et
• maintenir ledit équipement en place dans le terrain avec ce train de tiges tout en retirant du sol l'outil à âme tubulaire autour du train de tiges;
• pour l'installation successive d'équipements similaires:
• l'outil à âme tubulaire est entraîné dans le terrain et un premier équipement est introduit à l'intérieur de cet outil à âme tubulaire,
• un second équipement est installé en haut du premier équipement, et
• l'outil à âme tubulaire est retiré du terrain d'une manière telle que l'outil à âme tubulaire inclue ce second équipement, ce grâce à quoi ce second équipement est prêt à être descendu dans le terrain simultanément avec l'outil à âme tubulaire lorsque celui-ci sera entraîné dans le terrain en un autre emplacement;
• pour l'installation d'un équipement flexible, l'introduction dudit équipement comprend les étapes consistant à:
• dérouler l'équipement flexible à partir d'un tambour d'alimentation,
• l'introduire dans l'outil à âme tubulaire jusqu'à la position prédéterminée par rapport au terrain, et
• couper l'équipement flexible du tambour d'alimentation, avant ou après le retrait de l'outil à âme tubulaire hors du terrain,
• et l'outil à âme tubulaire est retiré du terrain d'une manière telle que cet outil à âme tubulaire inclue une nouvelle longueur de l'équipement flexible, ce grâce à quoi cette nouvelle longueur d'équipement flexible est prête à être descendue dans le terrain simultanément avec l'outil à âme tubulaire lorsque celui-ci sera entraîné dans le terrain en un autre emplacement,
• pour fixer une structure existante sur le terrain, le forage du terrain par entraînement dans celui-ci d'un outil à âme tubulaire est réalisé à travers un trou cylindrique à extrémité tronconique pratiqué dans cette structure et possédant un diamètre légèrement supérieur au diamètre de l'outil à âme tubulaire et, après retrait de l'outil à âme tubulaire, ledit équipement est fixé à la structure avec un bouchon tronconique correspondant au trou à extrémité tronconique,
• la modification de la compacité du terrain consiste en un compactage du terrain pour certains emplacements du traitement et en un décompactage du terrain avec utilisation d'équipements draînants, pour les autres emplacements,
• la modification de la compacité du terrain est réalisée de manière différente à différentes profondeurs le long de l'équipement.

In addition, all or part of the following annexed provisions may be used, in combination with the foregoing:

• the modification of the compactness of the ground is carried out with said tubular core tool;
• the tubular core tool consisting of a helical hollow auger, the method comprises the steps of:
• introduce this helical auger into the ground by screwing said auger into the ground, introduce the equipment from inside the hollow core of the auger and
• remove this auger from the ground by unscrewing said auger while imparting to the latter, for each rotation, an axial displacement different from its propeller pitch, whereby the compactness of the ground around said equipment is modified;
• the tubular core tool is subjected to vibrations when it is removed from the ground, whereby the compactness of the ground around said equipment is increased;
• said equipment is subjected to vibrations during the withdrawal of the tubular core tool from the ground, whereby the compactness of the ground around the equipment is increased;
• the method further comprises the step of introducing filler material around said equipment while the tubular core tool is removed, so as to constitute a sheath of filler material around said equipment;
• the method further comprises the step of carrying out a pressure injection of the ground around said equipment while the tubular core tool is removed by pumping a hardening liquid material such as a cement grout or a chemical grout in the terrain around said equipment;
• the tubular core tool being constituted by a hollow helical auger, the method further comprises, during the removal of this helical auger, the steps consisting in:
• create at least one widened hollow space in the ground around said equipment by raising the helical auger by a predetermined distance and
• introducing a filler material at the bottom of the helical auger to fill the aforementioned enlarged hollow space and to establish an enlarged zone or bulb of filler material around said equipment;
• a filler material is introduced through the space existing between the inner face of the tube constituting the core of the tubular core tool and said equipment while the tubular core tool is removed;
• drilling the ground by driving a tool with a tubular core in the latter also comprises the steps consisting in:
• introduce a drill string with a drilling tool inside the tubular core tool to drill a hard layer in the ground or an underlying rock using an auxiliary drive head acting on said drill string,
• remove this drill string and the drilling tool from the tubular core tool before introducing said equipment and performing the other steps;
• after drilling the ground by driving the tool with a tubular core in the latter, the method comprises the steps consisting in:
• introduce equipment fitted with a drilling tool into the tubular core tool by lowering it to the bottom of the tubular core tool and
• rotate said equipment using an auxiliary drive head to drill a hard layer in the ground or an underlying rock with the drilling tool before removing the tubular core tool from the ground while leaving said equipment and its drilling tool in the field;
• after having introduced said equipment inside the tool with a tubular core, the method comprises the steps consisting in:
• connect a drill string to the top of said equipment and
• hold said equipment in place in the ground with this drill string while removing from the ground the tubular core tool around the drill string;
• for the successive installation of similar equipment:
• the tubular core tool is driven into the ground and a first piece of equipment is introduced inside this tubular core tool,
• a second piece of equipment is installed at the top of the first piece of equipment, and
• the tubular core tool is removed from the ground in such a way that the tubular core tool includes this second equipment, whereby this second equipment is ready to be lowered into the ground simultaneously with the tubular core tool when the latter is trained in the field at another location;
• for the installation of flexible equipment, the introduction of said equipment includes the steps of:
• unwind flexible equipment from a feed drum,
• introduce it into the tubular core tool up to the predetermined position relative to the ground, and
• cut the flexible equipment of the supply drum, before or after removing the tubular core tool from the ground,
• and the tubular core tool is removed from the ground in such a way that this tubular core tool includes a new length of flexible equipment, whereby this new length of flexible equipment is ready to be lowered into the terrain simultaneously with the tubular core tool when the latter is driven into the terrain at another location,
• to fix an existing structure on the ground, the drilling of the ground by entrainment in this one of a tool with tubular core is carried out through a cylindrical hole with frustoconical end practiced in this structure and having a diameter slightly greater than the diameter of l tool with a tubular core and, after removal of the tool with a tubular core, said equipment is fixed to the structure with a frustoconical plug corresponding to the hole with frustoconical end,
• the modification of the compactness of the ground consists in compacting the ground for certain locations of the treatment and in uncompacting the ground with the use of drainage equipment, for the other places cements,
• the modification of the compactness of the ground is carried out differently at different depths along the equipment.

• 1. Forage du sol.
• 2. Mise en place d'une armature, d'un équipement métallique ou plastique ou d'un matériau d'apport.
• 3. Constitution d'une gaine de coulis, de mortier ou de matériau rapporté autour de l'armature ou de l'équipement métallique ou plastique.
• 4. Compactage mécanique du sol (ou décompactage) autour de l'armature ou de la gaine, à la fois par effet mécanique pur et/ou par effet de vibrations ou de chocs.
• 5. Injection du sol sous pression autour de l'ouvrage.
• 6. Création de zones élargies de l'ouvrage, remplies de matériaux d'apport, avec éventuelle mise en compression du terrain autour des parois de l'ouvrage et/ou injection de celui-ci.

The method makes it possible, using a single tool, and in a single descent and ascent operation thereof, to carry out all of the following operations:

• 1. Drilling the soil.
• 2. Installation of a frame, metallic or plastic equipment or filler material.
• 3. Constitution of a grout, mortar or added material sheath around the metal or plastic frame or equipment.
• 4. Mechanical compaction of the soil (or decompaction) around the reinforcement or the sheath, both by pure mechanical effect and / or by vibration or shock effect.
• 5. Injection of the soil under pressure around the structure.
• 6. Creation of enlarged zones of the structure, filled with filler materials, with possible compression of the ground around the walls of the structure and / or injection thereof.

The scope of the process is very wide, since it applies to the majority of the problems of soil treatment or construction of linear structures in these requiring any combination of the above operations.

It makes it possible to combine all the operations mentioned at will, both with regard to their relative importance at each location and with regard to the choice of operations to be applied according to the different depth zones of the structure.

It is also possible to carry out mixed treatments, comprising either widening, compacting or unpacking depending on the depth of the terrain concerned.

One of the characteristics of the process is that the treatment of the ground around the structure can be done after the reinforcement has been put in place and around it, thus achieving a perfect junction between the treated ground and the reinforcement.

D. Description of Tool and Machine

• a) des moyens de support,
• b) des moyens de déplacement longitudinal incluant un mât,
• c) une tête annulaire tournante d'entraînement supportée par le mât et pouvant tourner dans les deux sens, et
• d) une tarière hélicoïdale à âme tubulaire raccordée à cette tête tournante pour pénétrer dans le terrain, caractérisé en ce qu'il comprend en outre:
• e) des moyens pour amener un desdits équipements dans le tube formant âme de la tarière à âme tubulaire à travers la tête annulaire tournante d'entraînement,
• f) des moyens pour asservir l'une à l'autre la vitesse de déplacement axial et la vitesse de rotation de la tarière hélicoïdale à âme tubulaire, ce grâce à quoi il est possible d'obtenir un compactage ou un décompactage prédéterminés du terrain autour dudit équipement lorsqu'on retire la tarière hélicoïdale à âme tubulaire.

According to a second of its aspects, the invention proposes an apparatus for the treatment of land and the successive installation of equipment in a land, comprising:

• a) support means,
• b) means for longitudinal displacement including a mast,
• c) an annular rotating drive head supported by the mast and capable of rotating in both directions, and
• d) a helical auger with tubular core connected to this rotating head to penetrate the ground, characterized in that it further comprises:
• e) means for bringing one of said pieces of equipment into the core tube of the auger with a tubular core through the rotating annular drive head,
• f) means for controlling the axial displacement speed and the rotation speed of the helical auger with tubular core to one another, whereby it is possible to obtain a predetermined compaction or decompaction of the ground around said equipment when removing the helical auger with tubular core.

• l'appareil comprend en outre un outil de forage inférieur déconnectable raccordé temporairement à l'extrémité inférieure de la tarière à âme tubulaire;
• l'appareil comprend en outre un dispositif de presse-étoupe pour effectuer une injection tandis que la tarière à âme tubulaire est remontée d'un train de tiges ou de l'équipement du trou suivant;
• la tête tournante d'entraînement comprend un système composé rotation-percussion ou rotation-vibration;
• l'appareil comprend en outre au moins un tube fixé le long de l'âme tubulaire de la tarière hélicoïdale à âme tubulaire pour amener un matériau d'apport autour et le long dudit équipement;
• l'appareil comprend en outre une tête d'entraînement auxiliaire supportée par le mât et indépendante de la tête annulaire tournante d'entraînement, pour agir sur ledit équipement placé à l'intérieur de la tarière hélicoïdale tandis que la tête annulaire tournante d'entraînement actionne la tarière hélicoïdale.

In addition, all or part of the following annexed provisions may be used, in combination with the foregoing:

• the apparatus further comprises a disconnectable lower drilling tool temporarily connected to the lower end of the auger with a tubular core;
• the apparatus further comprises a cable gland device for performing an injection while the auger with tubular core is raised from a drill string or from the equipment of the next hole;
• the rotating drive head comprises a composite rotation-percussion or rotation-vibration system;
• the apparatus further comprises at least one tube fixed along the tubular core of the helical auger with tubular core to bring filler material around and along said equipment;
• the apparatus further comprises an auxiliary drive head supported by the mast and independent of the rotating annular driving head, for acting on said equipment placed inside the helical auger while the rotating annular driving head operates the helical auger.

D 1. The tool

• a) The tool is a tool with a hollow tubular core, for example a conventional continuous auger. In the following of this description, we will place in this case in order to clarify the presentation (although a tool with a hollow tubular core different from an auger may be used). The auger can either be constructed in one piece, or consist of unitary elements assembled together. It may or may not be provided at its base with a tip or drilling tool made of hard metal, for example in the form of a spin, enabling it to cross hard benches in the ground. This drilling tool can either be fitted with soft friction at the base of the tube constituting the core of the auger, or connected to this tube by a bayonet system or a coarse thread with a few threads, greased at the time of assembly.
• b) The foot tool, if used, is intended to be left at the bottom of the borehole after the drilling operation. The decoupling between the foot tool and the auger is done either not flushing under fluid pressure (compressed air, water, grout or other), or by unscrewing or removing the bayonet, once the tool is planted in the ground at the base of the drilling.
• c) The foot tool can be provided at its upper part, facing the inside of the tube constituting the core of the auger, with a female thread with large pitch surmounted by a conical bore serving as a guide, intended to receive an end with male thread fixed to the base of the armature to introduce, in case there is a reinforcement. It is thus possible to couple the foot tool and the frame by screwing. The coupling thus produced can allow:
  • 1. to facilitate the unscrewing of the lower tool if necessary, by acting on the armature to transmit the torsional torque (motor or resistant) necessary;
  • 2. to facilitate, if necessary, keeping the frame in place during the subsequent reassembly of the auger, by providing an anchor point in the ground at the base, by the grip of the foot tool in the ground by place (for example if it is helical).
• d) The foot tool can be fitted with a harpoon-like system with elastic metal blades initially folded against its shaft during its descent, but deploying in the ground and preventing it from going up, so as to improve its adhesion in the soil against any tearing effect once it is uncoupled from the base of the auger.
• e) The tube forming the core of the auger may or may not be fitted internally or externally with another tube, of smaller diameter, attached to one of its generatrices, which will possibly be used to bring grout or another material in fluid phase to the base of the auger. In this case, the base of the tube forming the core can be equipped with an annular distribution ramp allowing distribution of the fluid over its entire periphery. The orifices may or may not be provided with one-way flow valves.
• f) Other annex tubes can also be arranged, if necessary, along other generatrices of the tube forming the core of the auger, opening at different heights along the latter.

D 2. The Machine

• a) The machine is essentially constituted by a very long mast (a few meters longer than the length of the reinforcement to be put in place). A mast shorter in length than the length of the frame can also be used, but in this case, an auger made of several elements should be used. This mast is carried by a heavy carrier, for example a chaser. It carries a powerful rotation head, for example hydraulically controlled, allowing rotation in both directions and sliding along the mast under the effect of a reversible advance system (by chain, jack, winches or any other process ).
• b) The drive head may or may not include a mixed rotation-percussion or rotation-vibration system, thereby making it possible to improve the compaction of the soil around the frame. If the drive head is purely rotary, it can also be surmounted by a percussive head or a vibrator sliding along the mast, which can come to rest on it and start operating at the desired time during operations.
• c) The drive head is annular and allows passage through its center. The upper part of the head is connected via a conventional hydraulic reel with rotating joint and a swan neck tube to an injection station for sending the materials (for example cement grout, mortar , concrete). This tubing is provided with a straight branch ending in a flange in the axis of the auger. The flange is closed either by a simple cover or by a cable gland system.
• d) For the introduction of the reinforcements, the machine is provided either with a simple winch intended for lifting the reinforcements along the mast, or with a barrel system allowing the feeding of several reinforcements, or with a reel carrying a coil of reinforcements if it is a question of introducing flexible reinforcements constituted for example of strands of cables or flexible bars.
• e) The machine can be fitted with a rotary or rotational percussion head, or a rotary vibrating head or not if one wishes to be able to act on the frame itself, the annex head being able to slide along the mast, independently of the main head.
• f) The machine can be equipped, at its base or in the upper part, with a powerful shears enabling the reinforcement to be cut to the appropriate length, in the case of continuous reinforcement unwound from a reel, or in the event of installation of armatures of variable lengths to be adjusted case by case.
• g) One can also use a non-annular drive head, but in this case, the head must be disconnected from the auger and reassembled along the mast or erased laterally before the introduction of the frame.

E. Sequence of Operations E 1. Drilling

• a) The drilling is carried out using the auger, in a conventional manner. The outside diameter of the auger turns is chosen according to the characteristics of the ground, and those of the machine. In the case where it is desired to form enlarged zones over the height of the structure, the outside diameter of the turns of the auger must be equal to the diameter of the enlarged zones to be formed.
• b) If the ground is sufficiently soft, you can drill without a foot tool. At the end of drilling, the inside of the tube constituting the core of the auger is cleaned using water, compressed air, or a mixture or emulsion of the two, for example by means of or annex tube (s), mentioned in D 1 e or in D 1 f above, or else a washing lance.
• c) If the grounds have hard benches, drill with the foot tool. The interior of the soul is then clean.
• d) The interior of the core can then be filled with grout, either by the annex tube or by the lance mentioned above.

E 2. Installation of the frame

The fitting of the frame is done from the inside of the tube forming the core of the auger. Several possibilities exist to install the frame:

a) The frame can be introduced inside the hollow core of the auger through the upper flange, possibly coupled with a steel bar serving as its temporary support at the head, by a bayonet type system.

The lower part of the frame is, if necessary, inserted and screwed into the conical entry thread of the foot tool. In the case of drilling without a foot tool, the frame can be fitted at its base with a harpoon-type anchoring system, against tearing, similar to that described above for the foot tool. Such anchors can be placed from place to place along the frame, both to oppose the tearing and to serve as centering devices.

After unscrewing, dislodging or flushing the foot tool, and possible uncoupling of the temporary support bar from the head of the frame, the head flange cover is closed.

b) The frame can be, after introduction, surmounted by a train of smooth rods fixed to an annex head remaining at the top of the mast. In this case, there is an absolute guarantee that the frame will remain in place when raising the auger.

The injection is then made either via the upper rod train and a tube incorporated in the frame, to its base, or by the annex tube, or by the annular space between the frame and the tube forming the core of the auger. In the first two cases, the auger core may or may not remain open at the top, in the third case, a cable gland must be provided at the top.

The rotation head being annular, leaves an interior passage for the rods. The auger thus rises around the drill string. The disconnection between the drill string and the armature is done when the base of the auger is raised enough along the mast to clear the place of the junction between armature and drill string.

c) The drill string referred to above can be formed by the reinforcement of the next hole itself. We are then dealing with a repetitive process, the machine being loaded during each operation with the reinforcement of the next hole, temporarily connected to the reinforcement of the hole in progress.

d) If the frame consists of strands of cables or flexible bars, it can be unwound from a supply coil fixed or not on the machine, and pass through a pulley at the top of the mast. It passes through the cable gland fixed to the upper part of the connection pipe described in paragraph D 2 c above.

The reinforcement is thus introduced into the ground on demand, according to possibly variable lengths. The machine then operates like a "sewing machine", driving variable lengths of armature into the ground. The shears, attached to the lower part of the machine, cut the reinforcements to the desired length for each of them. An additional head, at the top of the mast, provides the unwinding of the continuous reinforcement from the supply coil and its immobilization when raising the auger.

e) As an alternative to the previous processes a and b, the reinforcement can be introduced simultaneously with drilling, according to the following process: drilling is carried out each time with the reinforcement inside the core, either fixed at the head, for example by means of a temporary support bar, either fixed to the foot by screwing into the foot tool if there is one, or still held at its upper part by an annex head sliding the along the mast at the same time as the main head which drives the auger. The frame therefore descends this time at the same time as the auger unlike the cases described in a and b above, where the frame was lowered after the drilling operation.

When the auger rises, it rises around the next frame, previously presented in the axis of the auger. The use of the cable gland mentioned in paragraph D 2 c or of the additional tube described in paragraph D 1 e above, allows injection operations during the ascent.

If the armature is a flexible armature unwound from a spool, the shears fixed to the lower part of the mast cut the armature after raising the auger, after which the end of the following armature can possibly be fixed to a new foot tool, if used. The machine is then ready for the next drilling.

f) The process also makes it possible to build structures in the ground made up of a filler material such as, for example, concrete, mortar, grout, aggregates or sand. In this case, the frame is replaced by the material in question, put in place either by pumping, or by simple pouring inside the core, by means of a hopper fixed at the head of the tube.

g) Extension of the process to the case of soft ground surmounting a rock or a harder ground:

in this case, if it is necessary or desirable to place the base of the reinforcement (or the filling of filler material) at a certain height in the rock or hard ground, the procedure is as follows: drilling through the loose ground is done with the auger either open at the base, or provided at its base, as a foot tool, with the tool (tricone bit, drill bit or other) with the help of which the drilling in rock or hard ground. In the latter case, the drill string that will actuate the tool in question is possibly already present inside the auger when drilling soft ground. It is driven either by the main head or by a movable auxiliary head along the mast of the machine. After drilling into the rock, the drill string is extracted and the foot tool can either be retrieved or left in place at the bottom of the borehole. The drill string used may possibly be constituted by the reinforcement itself, if it is rigid enough to transmit the corresponding forces and provided that it includes a conduit for the perforating fluid (tubular reinforcement for example). The drilling tool is in this case left at the bottom of the hole, at the end of the frame.

E 3. Constitution of the sheath around The frame

When the fitting of the frame is complete, we start to raise the auger. The installation is then carried out by pumping or by filling a material (for example cement grout, mortar, micro-concrete), either in the auger core tube, around the frame, or by the auxiliary tube. described in paragraph D 1 e above. The material in question then takes the place left by the auger tube around the frame. It constitutes around it a protective and support sheath and connection to the surrounding ground if it is a hardening material (for example grout, mortar or concrete).

E 4. Mechanical Compacting (or Decompacting) of the Ground Autdur of the Reinforcement

• a) During the ascent of the auger, and at the same time that the sheath described above is put in place, the auger is rotated in the opposite direction to the direction of drilling, while gradually raising it.
• b) The reverse rotation speed is at least that which corresponds to a simple unscrewing of the propeller, taking into account the vertical extraction speed and the pitch thereof, leaving in place the materials which are around the auger tube between the turns of the propeller. A slightly higher reverse speed will compact the ground. The compaction is done by simple mechanical effect, by pressure of the turns of the auger on the ground which it traps, and by effect of drive of the surrounding loose ground which tends by its own weight to take the place of the voids created by the compaction. Filler materials can be poured around the auger at the head of the borehole to compensate for the settlements created by compaction.
• c) Mechanical compaction is improved if desired by impact or vibration effect using the special heads described in paragraph D 2 b above. This effect can be very significant and considerably increase the radius of action of compaction in the soil.
• d) Conversely, it is also possible by effect of the auger, to loosen the ground around the frame, by choosing an adequate rotation speed compared to the ascent speed. By installing either the auger core or a draining tube, or a sand or gravel filling, or all of the two, a drain with improved capture power is obtained. It is thus possible to carry out a general drainage treatment of a soil by installing a network of multiple drains of this type.
• e) Mixed systems are also possible, comprising the drainage of certain layers and the compaction of others, according to all the desired combinations.
• f) Compaction by percussion or vibration is carried out either by action of the special head (s) described in paragraph D 2 b above on the auger, or by action of the additional head described in paragraph D 2 e on the frame itself, in the cases described in paragraphs E 2 a to E 2 e and E 2 g above, where the frame is either extended by a string of rods, or extended by l next frame, be continuous.

In the case where the armature itself is vibrated, there is obtained a compacting effect of the materials constituting the sheath around the armature and the surrounding soil. The two actions (on the auger and on the frame itself) can also be combined, making it possible to obtain the maximum compaction desired.

E 5. Treatment of the Ground Around the Reinforcement By Pressure Injection

• a) During the unscrewing and raising operation, accompanied by the mechanical compaction of the soil described above, it is possible to inject under pressure cement grout, mortar or another grout, depending on the nature of the soil.
• b) The injection is made, like the constitution of the sheath described in E 3 above, either by the inside of the auger core, around the frame, or by the auxiliary tube described in D 1 e, or possibly by the other annexed tubes described in D 1 f. It is then in principle, but not necessarily, the same material as that of the sheath. This takes the place left free around the frame, as well as that left by the turn of the propeller during unscrewing and it enters the ground by injecting it.
• c) One thus obtains, by the combination of the effects of the operations above, a ground at the same time reinforced, mechanically compacted (by simple mechanical effect and / or by dynamic mechanical effect of percussion or vibration) and injected under pressure. The land is treated in place, around the frame, to which it is perfectly linked, gradually, over its entire height. It is therefore a particularly effective and complete treatment and reinforcement process. The compaction forces obtained mechanically and by injection combine and add up and it is possible to obtain all the desired degrees of compaction
• c) The auger rotation and extraction speeds, as well as the grout injection pressure and flow rate, and the importance of dynamic compaction (percussion or vibration), can be controlled, so as to obtain all the combinations possible parameters, as well as maintaining, according to constant ratios, the combinations of parameters best suited to each particular case.

E 6. Creation of Enlarged Zones Around the Reinforcement

• a) It is possible to create around the framework enlarged zones (bulbs) made of filler materials (for example grout, microbeton, mortar, or granular filling materials). To do this, simply raise the auger, without any rotational movement, while injecting the material by pumping, or by simple gravity filling. If necessary, the auger prints a very slow rotational movement in the direction of drilling to avoid mixing of the filler materials with the ground. In the case of installation by pumping, the mixture constituting the material is prepared outside in a mixing, kneading and pumping unit. It is sent under pressure to the base of the auger by an injection pump, either through the interior of the hollow core around the frame, or through the auxiliary tube described in D 1 e. The pressure maintained at the base allows complete filling of the vacuum created by the ascent of the auger to a diameter equal to the outside diameter of the propeller. The surrounding terrain is kept compressed by the pressure of the fluid. It can be injected at higher pressure if necessary.

• b) Ce type d'élargissement peut être créé soit à la base de l'ouvrage, soit à une hauteur quelconque le long de celui-ci. Des élargissements multiples peuvent également être créés à des hauteurs quelconques, séparés par exemple par des zones de terrains compactés.
• c) La réalisation des zones élargies peut aussi être exécutée par un procédé d'injection dirigée à très haute pression (procédé type "jet grouting") à l'aide de tiges spéciales descendues à l'intérieur de l'âme. Dans ce cas, le diamètre de l'élargissement peut devenir supérieur à celui de la spire de la tarière.

The bulbs can also be made of draining materials.

• b) This type of widening can be created either at the base of the structure or at any height along it. Multiple enlargements can also be created at any height, separated for example by areas of compacted land.
• c) The realization of the enlarged zones can also be carried out by a process of injection directed at very high pressure (process type "jet grouting") using special rods lowered inside the core. In this case, the diameter of the enlargement may become greater than that of the auger turn.

F. Example of Construction of a Linear Structure in the Ground = Case of an Anchor Tie

The following figures show the different construction phases in the ground of a particular structure: here it is a tie rod.

Figure 1 shows the installation of the machine at the location of the work to be executed.

Figure 2 shows the drilling using the auger (1), to the depth of the final structure. The auger is equipped with a foot tool (2), intended to allow the crossing of the hard benches of the ground. The foot tool (2) is screwed by means of a coarse thread with a right pitch on the tube forming the core of the auger. When screwing, the thread is greased, which will facilitate its subsequent unscrewing. During the drilling operation, the auger turns to the right (clockwise). The foot tool carries on its upper face, a female thread with large right-hand threads surmounted by a conical bore.

FIG. 3 represents the positioning of the frame (3), inside the tube forming the core of the auger, by means of the axial tube (4) surmounting the annular rotation head (5) . Before the fitting of the frame, the tube forming the core of the auger was previously filled with cement grout, either by a lance lowered inside the tube, or by an auxiliary tube of small diameter running the along a generatrix of the tube forming the core. The frame, which is here a simple bar of high strength steel, is provided at its lower end with a nozzle carrying a coarse thread on the right. When the frame has been lowered to the bottom of the tube, its threaded end is introduced into the female thread of the foot tool, guided by the tapered bore above it. The armature is screwed onto the foot tool, after which, by continuing to rotate the armature to the right (clockwise), the tool is unscrewed. stand, which separates from the auger tube.

Figure 4 shows the creation of a widening (6) at the bottom of the structure, in line with the sealing zone of the tie in the ground. The widening is obtained by simply raising the auger, while sending cement grout under pressure via the swan neck tube (7) located above the rotation head. During this operation, the frame remains at the bottom of the borehole while the auger rises. The diameter of the widening created (anchor bulb of the tie rod) is equal to the outside diameter of the helical spiral of the auger. The ground around the enlargement is kept in compression by the pressure of the grout pumped by an injection pump.

FIG. 5 represents the compaction and the injection treatment of the ground (8), around the reinforcement, over a height of a few meters above the widening made in the lower part. Compaction is done purely mechanically, by rotation of the auger in the opposite direction to the direction of drilling, as it rises, and by dynamic effect through the action of shocks or vibrations exerted by the rotation head- percussion or rotation-vibration (5) located at the top of the auger and by injection under high pressure of cement grout into the ground via the tubing (7). The zone of compacted terrain, above the widening forming the anchor of the tie rod, serves to transmit to the surrounding terrain the forces exerted by the upper part of the widening by "reverse point effect", by analogy with "l 'tip effect' down exerted on the ground by the base of a pile working in compression and as opposed to the effect of 'lateral friction' which is exerted along the contact surface between the barrel of the extended area and terrain. It should be noted that the creation of an enlarged zone in the lower part considerably improves the capacity of the anchoring, because the increase in diameter improves the effect of "lateral friction" all the while allowing the development of a significant "reverse peak effect". The improvement obtained would be equivalent in the case of a pile or micropile working in compression. A pile-drawing, sometimes working in compression, sometimes in traction, benefits from the improvement in both directions.

Figure 6 shows a simple filling annular space (9) around the frame, corresponding to the location previously occupied by the tube forming the core of the auger, by cement grout. It was assumed that on the upper part of the structure, corresponding to the free length of the tie, the ground no longer needed to be) compacted. It is obvious that compaction can always be carried out if desired, for example if it was to guarantee the reinforcement against the risk of buckling if it were a micropile.

FIG. 7 represents the finished tie-rod, with its frame (3), its anchoring zone at the base (6), its zone of ground mechanically compacted and by injection (8) and its free height simply surrounded by a sheath of protection (9).

This type of tie rod, installed in a short time, in a series of simple and effective operations, is particularly well anchored in the ground and capable of great performance.

G. Areas of Process Use

• a) The process can be used industrially for:
  • 1. compaction and injection treatment of soils,
  • 2. soil drainage,
  • 3. the construction of linear structures in the ground, with or without reinforcement, and for which the state of compaction of the soil around the structure must be checked or modified,
  • 4. the construction of flat structures in the ground (see below paragraph I).
• b) Compaction, drainage, or mixed treatments can be applied to large areas of land, for example if it involves treating the foundation soil before the construction of a set of buildings or structures of art, or if it is a question of stabilizing a given volume of ground, for example to oppose a risk of sliding or to modify the characteristics of thrust or abutment behind a work.

In this case, the ground, mechanically compacted and injected, may be provided with reinforcements resistant to compression or traction, or else drains. It is then a compacted, injected and reinforced ground, or else an uncompacted and drained ground.

The mesh of the treatment (distance between neighboring boreholes) is defined according to the nature and characteristics of the terrain, the result to be obtained, and the radius of action of each unitary treatment.

• c) En ce qui concerne les applications du procédé à la construction d'ouvrages linéaires dans le sol avec traitement du terrain autour de l'ouvrage, on peut citer, à titre d'exemples non limitatifs:
  • 1. Les oieux ou microoieux: pour lesquels la création d'un bulbe à la base augmente la force portante, et le compactage du terrain autour du fût s'oppose aux risques de flambement en partie haute, tout en améliorant la portance par frottement latéral le long du fût. En cas de présence de terrains compressibles au-dessus de la zone de fondation, le compactage réalisé en partie supérieure s'oppose au développement ultérieur de frottements négatifs.
  • 2. Les tirants d'ancrage: pour lesquels la création d'un bulbe à la base augmente la résistance de l'ancrage par augmentation du frottement latéral, et par création d'un "effet de pointe renversé", et le compactage du terrain au-dessus de la zone d'ancrage permet la transmission au terrain environnant, lui-même traité et compacté, des efforts d'ancrage.

The reinforcement introduced is either metallic or plastic, or a simple filling of added materials. Compaction at the head of the borehole due to compaction is compensated by the addition of materials. Bulbs of materials or micro-concrete or other grout can be created at various heights. The improvement in soil characteristics obtained by this process can be considerable. In all cases, the enslavement between speed of rotation and ascent of the auger, importance of dynamic compaction (percussion or vibration) and the flow rates and pressure of injection or introduction of filling materials allows total control of the treatment. .

• c) With regard to the applications of the method to the construction of linear structures in the ground with treatment of the ground around the structure, there may be mentioned, by way of non-limiting examples:
  • 1. The eyes or micro-eyes: for which the creation of a bulb at the base increases the bearing force, and the compaction of the ground around the bole opposes the risks of buckling in the upper part, while improving the bearing by lateral friction along the barrel. In the presence of compressible soils above the foundation zone, the compaction carried out in the upper part is opposed to the subsequent development of negative friction.
  • 2. The anchor rods: for which the creation of a bulb at the base increases the resistance of the anchor by increasing the lateral friction, and by creating a "reverse point effect", and the compaction of the ground above the anchoring zone allows the transmission to the surrounding ground, itself treated and compacted, of the anchoring forces.

• il peut servir comme organe de protection de l'armature descendue ensuite à l'intérieur,
• il peut lui-même constituer le tirant ou le micropieu,
• il peut servir à une injection complémentaire s'il est muni de manchettes.

It should be noted that in the case of micropiles or tie rods, it is possible to introduce as reinforcement either the tie rod or the micropile itself, previously prefabricated, and comprising or not a tube with conventional sleeves for subsequent reinjection, either a tube, metallic or plastic, with or without injection sleeves (tube with sleeves), around which a sheath of grout or filler material is created when raising the auger. This tube can be used for various purposes:

• it can serve as a protection member for the frame then lowered inside,
• it can itself constitute the tie rod or the micropile,
• it can be used for a complementary injection if it is equipped with cuffs.

In the latter case, the internal reinforcement of the tie rod or micropile must be introduced subsequently, after the additional injection through the cuffs. The tube and / or the reinforcement can in some cases be lowered to a partial depth in the borehole, for example to the top of a bulb made of granular materials or concrete created at the base of the structure.

3. Injection boreholes: fitted with tubes, for example cuff tubes. For these holes, the adjustment of the degree of compaction of the ground around the tube with cuffs for example, at the same time as the progressive and controlled constitution of the plastic grout sheath over the entire height of the zone to be injected, as and when of the auger ascent, allows a very significant improvement and a rigorous control of the sheath created and its conditions of connection with the surrounding land. The possibility of pre-injecting the ground when raising the auger can be a considerable advantage, for example if it is a land with voids or decompressed areas.

In the case where the injection must comprise two or more phases, for example the first with a cement grout and the second with chemical gels, the first phase can be carried out with cement grout directly from inside the auger or the annex tube D 1 e, the second phase alone being carried out subsequently by the cuff tubes.

4. Drains or piezometers: for which the creation of an area of decompressed ground around the structure, together with the placement of a mass of filtering material (sand or gravel) around the tube, improves both the power of capture and that of filtration of fine elements. Piezometers or multiple drains can be installed, by decompressing the land in front of the layers to be captured and by compressing and injecting the land in front of the layers to be masked.

5. Water abstraction wells: for which the two preceding effects are even more essential. It should be noted that in the process described, drilling is done without the use of drilling mud, bentonite or the like. This therefore avoids both pollution of the aquifers to be captured and any clogging effect on the ground or in the vicinity of the borehole walls. On the contrary, the soil surrounding the filter bed is decompacted, thus greatly facilitating the development and the capturing power of the structure.

As with piezometers and drains, composite catchment works can be installed, by decompressing the land in line with the layers to be captured, and by compressing and injecting the layers to be masked.

Enlarged catchment areas, with a greater draining bed, can be created at different heights along the structure.

6. Measuring devices: they can be various devices such as inclinometers, tasometers, point piezometers with measuring cell, or any other type of device requiring, in addition to the installation of the device itself and a possible sheath of filler material, adjusting the degree of compactness (or impermeability) of the surrounding land to a suitable value.

7. Other structures: the process can be applied to any linear structure in the ground requiring any combination, and which may vary along its height, of the various parameters already mentioned: presence or absence of a reinforcement, coating with a sheath in hardenable material or filler material, compaction or decompaction of the soil around the structure, pressure injection.

H. Device for Linking the Reinforcement with the External Structure

To be able to execute works such as micropiles or tie rods by the process described above, and if these works must be carried out through a slab, a wall or a reinforced concrete work already built, one must be able to introduce the auger through the work , which requires a passage of diameter much larger than the diameter of the armature to be put in place. In addition, it must be possible to carry out the continuity of the sealing protection in the case where there must be a sheet of pressurized water under the slab or the structure, or outside the wall, at the final stage after construction of the structure.

H 1. Case of a Frame Working in Traction (Anchor Tie)

• a) The special tie rod head required is shown in Figure 8. It includes:
  • a conical plug (11) made of precast concrete or concrete poured in place (armed with a hoop and a tight reinforcement),
  • a flange (12) welded to the tube (13) for external protection of the tie rod, on which the sealing connection (15) will come to bear, a bed of sand (or first phase concrete) (14) on which will bear the collar (12),
  • a sealing fitting (15), making it possible to connect the general sealing membrane (16) of the structure to the tube (13) protecting the tie rod. The sealing connection is either glued or simply placed on the flange (12),
  • a layer of concrete to protect the sealing connection (17).
• b) The special sealing head can either be built in the thickness of the slab, the wall or the structure, as shown in figure 8, or partially built in elevation compared to the bare concrete structure. , as shown in Figure 9, so as to ensure good transmission of tensile forces to the concrete structure. It may include a recess allowing the fitting of a tie head not exceeding the outside of the concrete, as shown in FIG. 10.
• c) During drilling, the fitting of the reinforcement and materials and the extraction of the auger, a fur (removable metal tube provided with a support flange at the head), protects the general waterproofing membrane , returned along the walls of the pilot hole in the concrete.
• d) The upper conical plug, if it is made of precast concrete, may or may not be bonded to the resin inside the corresponding reservation of the concrete structure. If it is not glued, it can remain removable, allowing then a possible repair of the tie (for example surfacing) if necessary.

H 2. Case of an Armature Working in Compression (Pile or Micropile)

In this case, shown in Figure 11, the conical plug (11) of precast concrete or concrete poured in place, is located at the bottom of the structure, either in the thickness of it as shown in the figure, or partially projecting downward, so as to ensure good transmission of the compressive forces to the concrete structure. The sealing connection (12) is simply placed (or glued) on the upper face of the conical plug (11). It is overcome a protective concrete (13) poured last, and the shape of which can be slightly conical if it is necessary to withstand significant hydrostatic underpressures.

H 3. Case of a Frame that Can Work Alternately in Compression or in Traction

The pile-pulling head, combination of the two previous cases, is then doubly conical, the seal being connected to a protection tube of the frame provided with a flange placed on the upper face of the lower plug. It is shown in Figure 12.

I. Application of the Process in the case of Planed Works 1.1 - State of the art

In the current state of the art, a flat structure is most often made in the ground either by substitution or by injection.

For example, if it is a question of creating a retaining wall in the ground before the opening of a excavation, one digs a trench in the ground and one replaces this one for example by reinforced concrete (process diaphragm wall). If it is a question of creating a waterproof wall in the ground, one proceeds either as above, or by injection. If the excavation or the embankment already exists or if they are in the course of execution and require a support, one proceeds most often to a surface coating (shotcrete or laid concrete), anchored or not in the ground by tie rods sealed in it.

If it is a question of realizing a drainage veil, one installs for example a network of linear drains, or more rarely, one constructs a draining trench by replacing the ground by a draining material.

All these processes are essentially based on the use of elements foreign to the soil which are introduced in place of the original land (concrete, various supports) or in it (grout, drains, tie rods, etc).

The process proposed here aims to constitute the flat structure (retaining, sealing, drainage or composite structure) by the mass of the land itself, suitably treated for this purpose.

1.2 - Principle of Processing

• a - S'il s'agit d'un ouvrage de soutènement et/ ou d'étanchéité, le sol est:
  • 1. compacté mécaniquement
  • 2. injecté
  • 3. armé.

It consists in constituting the structure by the soil itself, subjected to the following treatments:

• a - If it is a retaining and / or waterproofing structure, the soil is:
  • 1. mechanically compacted
  • 2. injected
  • 3. armed.

• b - S'il s'agit d'un ouvrage de drainage, le sol est:
  • 1. décompacté mécaniquement
  • 2. équipé de drains et/ou de puits de pompage
  • 3. les équipements sont entourés de massifs filtrants, avec création éventuelle de bulbes élargis.

Compaction is obtained by simple mechanical effect, possibly combined with percussion and / or vibration effects. The frame is coated with a sheath which secures it to the ground. It can play a passive or active role (prestressing).

• b - If it is a drainage structure, the soil is:
  • 1. mechanically unpacked
  • 2. Equipped with drains and / or pumping wells
  • 3. the equipment is surrounded by filter media, with possible creation of enlarged bulbs.

The essential characteristic of the process resides in the fact that the terrain itself is deeply altered and modified by the transformations that it undergoes by the combination of the preceding effects, and that after this treatment carried out inside the volume of the plan structure to be built, it constitutes this structure itself.

1.3 - Application mode A. Case of Support Structures

In the case of retaining structures, for example vertical or inclined retaining walls, it is essentially a question of obtaining a mass of mechanically compacted soil, injected and reinforced, and possibly precompressed, capable of its new characteristics after treatment, resist the pushing forces of the ground, and possibly of the water, which it will have to retain.

• a - Le terrain est compacté mécaniquement, par simple effet mécanique des spires de la tarière, comme expliqué aux paragraphes E4a et E4b ci-dessus. Ce compactage mécanique simple est complété au besoin par effet de percussion et/ ou par effet de vibration, agissant sur la tarière au cours de sa remontée et/ou sur l'armature elle-même, comme expliqué aux paragraphes E 4 c et E 4 f ci-dessus.

The essential elements of treatment are:

• a - The ground is compacted mechanically, by simple mechanical effect of the turns of the auger, as explained in paragraphs E4a and E4b above. This simple mechanical compaction is supplemented if necessary by a percussion effect and / or by a vibration effect, acting on the auger during its ascent and / or on the frame itself, as explained in paragraphs E 4 c and E 4 f above.

• b - Le terrain est traité par injection sous pression, comme expliqué au paragraphe E5.

The effect of this compaction is to modify the characteristics of the soil, allowing it to transmit greater forces while reducing the corresponding deformations of the soil mass. Initial settlements at the time of compaction can be compensated by material inputs, either in the solid phase (for example aggregates, sand, gravel, etc.), or in the liquid phase (for example mortar, concrete, grout, etc.), introduced either at the head of the borehole around the auger, either at the very heart of the solid mass, through the interior of the hollow core of the auger, or else via the special annex tube described in the paragraph Die above. The introduction of the filler material (s) can be carried out by any combination of the above three means.

• b - The terrain is treated by pressure injection, as explained in paragraph E5.

This injection treatment completes and reinforces the effect of the compaction described above, making it possible to obtain, depending on the case, mechanical characteristics of the treated ground very much greater than their initial values.

• c Le terrain est armé, c'est-à-dire qu'il est muni d'armatures selon une maille correspondant à la maille du traitement ou à une maille multiple de celle-ci. Les armatures sont liées au terrain par une gaine qui les solidarise avec celui-ci.

In addition, in the case of retaining structures which must retain water in addition to resistance to earth pressure, the injection makes it possible in certain cases to constitute a wall of land which is both waterproof and resistant.

• c The land is reinforced, that is to say it is provided with reinforcements according to a mesh corresponding to the processing mesh or a multiple mesh thereof. The reinforcements are linked to the ground by a sheath which secures them to it.

The method of fitting the reinforcements and the sheath is explained in paragraphs E2 and E3 above.

The reinforcements can be made up of metallic, plastic or other materials, or even fillings of filler materials, placed in solid phase (for example gravel, dry concrete) or liquid (for example concrete, mortar, concrete, etc.).

Enlarged zones of the sheath or of the filling of filler materials can be created in certain places of the treatment, as explained in paragraph E6,

• 1. Elles peuvent travailler en compression, en traction et/ou en cisaillement, en liaison avec le terrain auquel elles sont liées par l'intermédiaire de la gaine qui les entoure: dans ce cas, elles constituent un renforcement du terrain et participent en tant que telles à l'amélioration de ses caractéristiques mécaniques.
• 2. Elles peuvent servir à transmettre des efforts, dans leur axe, à la périphérie de la masse de sol traitée: dans ce cas, elles travaillent par exemple en micropieux, transmettant des efforts de compression vers la base de l'ouvrage, ou bien en tirants, permettant l'ancrage de l'ouvrage dans le sol à la périphérie de celui-ci.
• 3. Ces effets peuvent être combinés. De plus, les armatures peuvent être utilisées pour réaliser une précontrainte du terrain, par ancrage dans le sol au voisinage ou sous l'ouvrage et mise en tension par appui sur un organe de répartition situé à l'extrémité libre. Dans un tel cas, le sol est non seulement compacté, injecté et armé, mais il est aussi précomprimé, ce qui peut être utile dans les cas où on veut éviter l'apparition de contraintes de traction dans le massif du sol traité.
  • d - Les différents effets ci-dessus (compactage, traitement par injection, armature, précompression du terrain) peuvent être utilisés selon toutes les combinaisons souhaitables, selon les cas, en mettant en oeuvre soit la totalité des effets, soit une partie d'entre eux seulement.
  • e - L'importance relative des différents effets entre eux peut être asservie à l'aide de dispositifs d'asservissement sur la machine de, mise en oeuvre et son unité d'injection associée, la valeur relative des différents paramètres pouvant varier selon les différentes zones de l'ouvrage à constituer.

The role of reinforcements can be multiple:

• 1. They can work in compression, in tension and / or in shear, in connection with the ground to which they are linked via the sheath which surrounds them: in this case, they constitute a reinforcement of the ground and participate as as such to the improvement of its mechanical characteristics.
• 2. They can be used to transmit forces, in their axis, at the periphery of the mass of soil treated: in this case, they work for example in micropiles, transmitting compression forces towards the base of the structure, or by tie rods, allowing the anchoring of the structure in the soil at the periphery thereof.
• 3. These effects can be combined. In addition, the reinforcements can be used to prestress the ground, by anchoring in the ground in the vicinity or under the structure and tensioning by pressing on a distribution member located at the free end. In such a case, the soil is not only compacted, injected and reinforced, but it is also precompressed, which can be useful in cases where one wishes to avoid the appearance of tensile stresses in the solid mass of the treated soil.
  • d - The different effects above (compaction, treatment by injection, reinforcement, precompression of the ground) can be used according to all the desirable combinations, according to the cases, by implementing either the totality of the effects, or a part of them only.
  • e - The relative importance of the different effects between them can be controlled by means of control devices on the machine, implementation and its associated injection unit, the relative value of the different parameters being able to vary according to the different areas of the structure to be built.

B Case of Waterproofing Works

In the case of structures intended only for waterproofing, for example waterproof walls or sails in the ground, or waterproof rafts in the ground under a excavation, the two mainly used effects are mechanical compaction of the soil and injection under pressure of it.

The reinforcement of the soil can be associated with this treatment, for example by cuff tubes which can be used to carry out further complementary injections, wherever the need arises, as described in paragraph Gc3 above.

C Case of Mixed Structures - Waterproofing

A combination of the treatments described in A and B above is used.

D Case of Drainage Works

In the case of works intended for drainage, for example walls or curtains draining in the ground, or draining rafts (layer of draining ground under the raft of a work), it is essentially a question of obtaining a mass of soil unpacked and equipped with drains and / or pumping wells surrounded by filter media.

• a - Le terrain est décompacté mécaniquement, comme expliqué au paragraphe E4 ci-dessus.
• b - Le terrain est équipé de drains et/ou de puits de pompaqe, comme expliqué aux paragraphes Gc4 et Gc5. Les equipements sont normalement des tubes crépinés métalliques ou equ plastiques, mais peuvent être aussi, dans le cas des drains en particulier, des colonnes de matériaux d'apport drainant (agrégats, graviers ou sable par exemple), comme expliqué au paragraphe E2f. Des tubes piézométriques sont installés aux endroits nécessaires.
• c - Des massifs filtrants en matériaux d'apport sélectionnés sont constitués autour des tubes d'équipement des drains et/ou des puits de pompage, le long de la hauteur des terrains à capter.
• d - Des élargissements des massifs drainants (bulbes drainants) sont créés aux endroits propices (par exemple à la base des drains ou des puits de pompage), comme indiqué au paragraphe E6 ci-dessus.

The essential elements of treatment are:

• a - The terrain is mechanically unpacked, as explained in paragraph E4 above.
• b - The land is equipped with drains and / or pumping wells, as explained in paragraphs Gc4 and Gc5. The equipment is normally metallic or plastic strainer tubes, but can also be, in the case of drains in particular, columns of draining filler material (aggregates, gravel or sand for example), as explained in paragraph E2f. Piezometric tubes are installed in the necessary places.
• c - Filter media made of selected filler materials are formed around the equipment tubes of the drains and / or pumping wells, along the height of the land to be captured.
• d - Widening of the draining massifs (draining bulbs) are created in the favorable places (for example at the base of the drains or the pumping wells), as indicated in paragraph E6 above.

E - Case of Composite Structures Support-Drainage

a - When one seeks to carry out a retaining structure for the purpose of, for example, the excavation of a dig, one often finds oneself confronted with the presence of a sheet of water or of inflows of water in the ground to support. If the proposed retaining structure is waterproof, for example if it is a sheet pile wall or a concrete wall, it must resist the pressure of the water in addition to the land push.

The present process makes it possible to produce composite structures comprising a part intended for support and a draining part. The latter collects water from the ground and allows the groundwater to be folded down behind the retaining structure, thus eliminating the hydrostatic thrust of the ground water on the structure. This produces a two-layer retaining-drainage structure.

This process is obviously applicable to cases where it is possible without drawback to fold the web at the rear of the structure. It applies everything particularly in the case where the permeability of the ground behind the structure is relatively low, because in this case it is possible to overcome the pressure of the water on the retaining structure by means of a low water extraction.

b - With regard to the extraction of water, this can be done either using pumping in pumping wells, or by lateral outlet if there is one, or by drilling sub-horizontal drains from the excavation to communicate the draining part of the retaining structure with it, or from masonry wells located from place to place along the draining wall.

c - We can build by this process both bi-layer retaining-drainage walls, vertical or inclined, as horizontal bi-layer rafts, for example to strike in compacted-injected-reinforced-anchored ground by tie rods combined with a draining layer located below or above the previous one.

d - One can also build mixed walls support-drainage, for example by treating in support the upper part and in drainage the lower part of the wall.

F - Case of Waterproofing-Drainage Composite Works

The same process for bi-layer or mixed walls and bi-layer rafts can be applied to composite structures which must allow the waterproofing of a site to the right of a screen and its drainage downstream of it. .

In this case, the draining part of the bi-layer is no longer located upstream, but downstream of the sealed part.

G. - Complex Structures Support-Waterproofing-Drainage-Treatment of Land

All the combinations of the preceding cases can be envisaged, the process making it possible to produce all the walls, screens and bi-layer or multi-layer rafts in treated soil that it may be advantageous to produce. Likewise, the method can be applied to any combination of planar structures as above, with mass treatments and linear structures as described in the main patent application, or to any combination of the preceding structures with classic works.

1.4 - Examples of Plan Works Executed by the Process

The following examples are only an illustration of the process and do not constitute an exhaustive list of its possibilities. The process applies in all cases where one wants to build structures in treated soil by applying the technique which is the subject of the main patent application.

A - Retaining Wall in Compact Soil-Injected-Weapon (Vertical Treatment)

FIG. 13 represents a retaining wall in compacted-injected-reinforced soil produced before the excavation of the excavation (21). The processing is carried out here by three drilling lines (22), treated according to the present process. In each borehole, a reinforcement is introduced, which is here for example a simple bar of high strength steel. The reinforcements are surrounded by sheaths of cement or mortar grout which secure them to the ground. The ground itself, around the armature and the sheath, is mechanically compacted, by simple mechanical effect, possibly supplemented by percussion and / or vibration effects. It is injected under pressure, for example using a cement grout.

The land thus constituted then has characteristics such that it can support the land in its natural state located at the rear.

B - Retaining Wall in Compact Soil-Injected-Weapon (Inclined Treatment)

This example, shown in FIG. 14, is similar to the previous example, except that the treatment holes, oblique to the surface of the excavation, are carried out as the excavation progresses.

It is also possible to carry out inclined treatments, similar to those described in A by drilling parallel to the surface of the future excavation, in the case of inclined excavations (in slope).

C - Retaining Wall in Compact Soil-Injected-Weapon-Precomprime

Figures 15, 16 and 17 show retaining walls similar to the previous ones, but for which one wishes to add to the three effects of compaction, injection and reinforcement of the ground, a precompression of the latter by prestressing tie rods anchored in the ground under or behind the structure.

In the example shown, certain boreholes (22) are simply equipped with passive reinforcements, while certain others (23) are equipped with active anchor rods, sealed under the structure or at the rear thereof, in enlarged bulbs (2) in cement grout or mortar. The tie rods are tensioned, before opening the excavation or as it is excavated, on distribution structures (25), continuous or discontinuous, placed on the surface.

D - Bi-Layer Support-Drainage Wall

Figures 18, 19 and 20 show examples of bilayer retaining-drainage walls executed according to the principle set out in paragraph 1.3F above.

• 1. Un mur en sol compacté-injecté-armé (et éventuellement précomprimé), situé côté fouille, et destiné au soutènement. Ce mur est réalisé à l'aide de forages (22) ou (23), comme expliqué ci-dessus.
• 2. Un mur drainant situé à l'arrière, exécuté comme expliqué au paragraphe 1.3D ci-dessus à l'aide de drains et/ou de puits de pompage (26), entourés de massifs filtrants (27) et de sol décomprimé (28), avec création dans le cas présent de bulbes drainants élargis (29) à la base.

The bi-layer wall consists of two parts:

• 1. A wall in compacted-injected-reinforced soil (and possibly precompressed), located on the excavation side, and intended for support. This wall is produced using boreholes (22) or (23), as explained above.
• 2. A draining wall located at the rear, executed as explained in paragraph 1.3D above using drains and / or pumping wells (26), surrounded by filter media (27) and decompressed soil ( 28), with creation in the present case of enlarged draining bulbs (29) at the base.

The extraction of water for the drawdown of the water table at the rear of the retaining structure is done either by pumping in certain holes in the draining wall, as shown in Figure 18, or by evacuation through sub-horizontal drains (30) drilled from the excavation and coming to collect the water collected by the draining wall, as shown in FIG. 19, or again by natural lateral outlets if there are any or artificial ones (for example masonry wells located from place to place place along the draining wall).

FIG. 20 represents a mixed retaining-drainage wall in which the lower part of the boreholes situated on the ground side is treated in drainage, the upper part being treated in consolidation. The reinforcements, which in this case are tubular, are screened in the lower part and allow the drainage of the lower part.

E - Example of Composite Structure of Support-Drainage

Multiple configurations can be adopted to make retaining structures, associated or not with drainage, according to the present process.

Figure 21 shows an example of such a work. In the case shown, a front inclined wall (32) consisting of reinforced-compacted-injected-precompressed ground by tie rods anchored in the underlying soil, is completed by a network of prestressed tie rods inclined in the other direction (33). All of the tie rods are tensioned on a distribution slab (25) located on the surface. A draining wall (34) ensures the folding of the tablecloth at the rear of the structure. The drawdown is completed at the bottom of the excavation by a simple network of sumps (35).

F - Waterproofing-Drainage Work

FIG. 22 represents a two-layer waterproofing-drainage wall intended for sealing a dike. In this example, the upstream part of the bi-layer is a sealing wall (36) in compacted ground, injected and provided with cuff tubes for possible subsequent re-injections. The downstream part of the bi-layer is a draining wall (37), the evacuation of the water collected by the draining wall being ensured by a network of sub-horizontal drains (38) opening into a gutter at the foot downstream of the dike.

G - Examples of Bi-Layer Rafts.

FIGS. 23 and 24 represent examples of a two-layer raft executed according to the present method.

The two examples relate to the execution of an excavation (39) in an aquifer. The excavation is supposed to be done under the protection of retaining walls in reinforced-compacted-injected-and possibly precompressed ground (40), or possibly of bi-layer retaining-drainage walls (see D above).

The raft treatment is normally carried out from ground level before excavation, and in any case from a level located above the folded level of the water table if there is a drawdown.

In the example shown in FIG. 23, the lower part of the bilayer raft is draining: it is constituted by a series of bulbs made of draining materials (41) (aggregates, sand or gravel for example) surrounding strainer tubes (42). In the upper part of the bi-layer, the tubes (43) extending the above strainer tubes (42) are full. They are surrounded by mechanically compacted and injected ground (44).

During the excavation of the lower part of the excavation, the water collected in the lower part of the bilayer is pumped out, which reduces or eliminates the hydrostatic underpressure under the upper part.

In the example shown in Figure 24, the arrangement is opposite: the lower part of the bi-layer (45) is made of reinforced-compacted-injected soil. It plays the role of a waterproofing raft and must oppose the hydrostatic pressure acting on its underside. The upper part of the bi-layer (46) is draining. It can be used, for example, to form a drain raft under the final structure.

It should be noted that in the examples described, the two parts of the two-layer apron can be executed using the same drilling, in a single sequence of rapid operations, as explained in paragraph E4e above.

In this case, the reinforcements can possibly play a composite role, allowing the drainage of the parts to be drained and the reinforcement of the parts to be reinforced.

1.5 Device for Connecting Reinforcements to an External Structure

See paragraph H above.

Claims (24)

1. Process for the treatment of ground and the successive installation of several items of equipment in different respective locations of this grounde, according to which process the ground is initially bored in one of the said locations by driving, into this ground, a tool (1) with a tubular core, having a tube forming its core and parts fixed on this tube defining an outer diameter of the tool; this process being characterized in that it also comprises the following additional stages consisting in:

introducing one of these items of equipment (3) inside the tool with a tubular core by causing it to descend to a predetermined position for the said item of equipment relative to the ground,

withdrawing the tool (1) with a tubular core from the ground while leaving the said item of equipment (3) inside the ground in its predetermined position,

modifying the compactness of the ground in at least a part of the volume corresponding to the outer diameter of the tool around the said item of equipment (3) by a mechanical action, during at least a part of the withdrawal of the tool (1) with a tubular core, and

repeating the above stages with each of the other items of equipment in each of the other respective locations.

2. Process according to Claim 1, characterized in that the compactness of the ground is modified with the said tool (1) with a tubular core.

3. Process according to Claim 2, the tool (1) with a tubular core consisting of a hollow helical auger, characterized in that it comprises the following stages consisting in:

introducing this helical auger (1) into the ground by screwing the said auger into the ground,

introducing the item of equipment through the inside of the hollow core of the auger and

withdrawing this auger from the ground by unscrewing the said auger while imparting to the latter, for each rotation, an axial displacement which is different from its helical pitch, as a result of which the compactness of the ground around the said item of equipment (3) is modified.

4. Process according to Claim 2, characterized in that the tool (1) with a tubular core is subjected to vibrations when it is withdrawn from the ground, by virtue of which the compactness of the ground around the said item of equipment (3) is increased.

5. Process according to Claim 1, characterized in that the said item of equipment (3) is subjected to vibrations during the withdrawal of the tool (1) with a tubular core out of the ground, by virtue of which the compactness of the ground around the item of equipment (3) is increased.

6. Process according to Claim 1, characterized in that it additionally comprises the stage consisting in introducing a supply material around the said item of equipment while the tool (1) with a tubular core is withdrawn, in such a manner as to constitute a sheath of supply material around the said item of equipment (3).

7. Process according to Claim 1, characterized in that it additionally comprises the stage consisting in effecting a pressurized injection of the ground (8) around the said item of equipment (3) while the tool (1) with a tubular core is withdrawn, by pumping a hardening liquid material such as a cement slurry or a chemical slurry into the ground around the said item of equipment.

8. Process according to Claim 1, the tool with a tubular core consisting of a hollow helical auger, characterized in that it additionally comprises, during the withdrawal of this helical auger, the following stages consisting in:

creating at least one enlarged hollow space (6) in the ground around the said item of equipment by raising the helical auger (1) by a predetermined distance and

introducing a supply material at the level of the bottom of the helical auger so as to fill the aforesaid enlarged hollow space (6) and to establish an enlarged area or bulb of supply material around the said item of equipment.

9. Process according to Claim 1, characterized in that a supply material is introduced by the space (9) which exists between the inner face of the tube constituting the core of the tube with a tubular core and the said item of equipment while the tool with a tubular core is withdrawn.

10. Process according to Claim 1, characterized in that the boring of the ground by driving a tool with a tubular core into the latter additionally comprises the following stages consisting in:

introducing a string of rods equipped with a boring tool (2) inside the tool with a tubular core so as to bore a hard layer in the ground or an underlying rock with the aid of an auxiliary driving head acting on the said string of rods,

withdrawing this string of rods and the boring tool out of the tool with a tubular core before introducing the said item of equipment (3) and performing the other stages.

11. Process according to Claim 1, characterized in that, after the boring of the ground by driving the tool with a tubular core into the latter, it comprises the following stages consisting in:

introducing an item of equipment equipped with a boring tool (2) into the tool with a tubular core by causing it to descend as far as the bottom of the tool (1) with a tubular core and

causing the said item of equipment to revolve with the aid of an auxiliary driving head so as to bore a hard layer in the ground or an underlying rock with the boring tool before withdrawing the tool with a tubular core from the ground while leaving the said item of equipment and its boring tool in the ground.

12. Process according to Claim 1, characterized in that, after the said item of equipment has been introduced inside the tool with a tubular core, it comprises the following stages consisting in: connecting a string of rods at the top of the said item of equipment and

maintaining the said item of equipment in place in the ground with this string of rods while withdrawing from the soil the tool with a tubular core around the string of rods.

13. Process according to Claim 1 for the successive installation of similar items of equipment, characterized in that:

the tool with a tubular core is driven into the ground and a first item of equipment is introduced inside this tool with a tubular core,

a second item of equipment is installed at the top of the first item of equipment, and

the tool with a tubular core is withdrawn from the ground in such a manner that the tool with a tubular core encloses this second item of equipment, by virtue of which this second item of equipment is ready to be lowered into the ground simultaneously with the tool with a tubular core when the latter is driven into the ground in another location.

14. Process according to Claim 1 for the installation of a flexible item of equipment, characterized in that the introduction of the said item of equipment comprises the following stages consisting in:

unwinding the flexible item of equipment from a supply drum,

introducing it into the tool with a tubular core as far as the position which is predetermined relative to the ground, and

cutting the flexible item of equipment from the supply drum, before or after the withdrawal of the tool with a tubular core out of the ground,

and in that the tool with a tubular core is withdrawn from the ground in a manner such that this tool with a tubular core encloses a new length of the flexible item of equipment, by virtue of which this new length of flexible equipment is ready to be lowered into the ground simultaneously with the tool with a tubular core when the latter is driven into the ground in another location.

15. Process according to Claim 1 additionally used to fix an existing structure on the ground, characterized in that the boring of the ground by driving a tool with a tubular core in the latter is performed through a cylindrical hole with a frustoconical end made in this structure and having a diameter which is slightly greater than the diameter of the tool with a tubular core, and in that, after withdrawal of the tool with a tubular core, the said item of equipment is fixed to the structure with a frustoconical plug corresponding to the hole with a frustoconical end.

16. Process according to Claim 1, characterized in that the modification of the compactness of the ground consists in a compaction of the ground for certain locations of the treatment and in a decompaction of the ground with the use of draining equipment, for the other locations.

17. Process according to Claim 1, characterized in that the compactness of the ground is modified in a different manner at different depths along the item of equipment.

18. Apparatus for the treatment of ground and the successive installation of items of equipment in a ground, comprising:

a) support means,

b) longitudinal displacement means including a mast,

c) an annular revolving driving head (5) supported by the mast and capable of revolving in both directions, and

d) a helical auger (1) with a tubular core connected to this revolving head so as to penetrate into the ground,

characterized in that it additionally comprises:

e) means for bringing one of the said items of equipment (3) into the tube forming the core of the auger with a tubular core, through the annular revolving driving head (5), and

f) means for controlling, the one by the other, the axial displacement speed and the speed of rotation of the helical auger with a tubular core, by virtue of which it is possible to obtain a predetermined compaction or a predetermined decompaction of the ground around the said item of equipment when the helical auger with a tubular core is withdrawn.

19. Apparatus according to Claim 18, characterized in that it additionally comprises a lower disconnectable boring tool connected temporarily to the lower end of the auger with a tubular core.

20. Apparatus according to Claim 18, characterized in that it additionally comprises a stuffing- box device to perform an injection while the auger with a tubular core is raised by a string of rods or by the item of equipment of the following hole.

21. Apparatus according to Claim 18, characterized in that the revolving driving head comprises a composite rotation/percussion or rota- tion/vibration system (5).

22. Apparatus according to Claim 18, characterized in that it additionally comprises at least one tube (7) fixed along the tubular core of the helical auger with a tubular core in order to bring a supply material around and along the said item of equipment.

23. Apparatus according to Claim 18, characterized in that it additionally comprises an auxiliary driving head supported by the mast and independent of the annular revolving driving head, so as to act on the said item of equipment placed inside the helical auger while the annular revolving driving head actuates the helical auger.

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