JP2001241033A - Ground improving method in which hardened columnar body can be anchored to hard supporting ground, and ground improving apparatus used for the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for economically and definitely anchoring a round columnar hardened body to the ground and the apparatus used for the method in hard bearing ground where the improvement is proposed such as rock layer, top of the underground structure or the bottom base of a pneumatic caisson. SOLUTION: A stirring vane 3 of a stirring head 2 attached to the lower portion of a grouting rod 1 connected to a freely liftable rotation drive apparatus 9 supported by a strut 8 is formed to an improved apparatus 10 extended diagonally downward for the grouting rod 1, the grouting rod 1 is penetrated to the improved proposed ground 11 and, without overexcavation, the grouting rod 1 is rotated and pulled up and a hardened columnar body 7 is formed on the hard supporting ground 12 while jetting a hardening material 6 onto the hard supporting ground 12 from a tip nozzle 4 of the stirring vane 3 provided by sloping downward.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soil improvement method for improving and hardening soft soil for the purpose of supporting and preventing settlement, and comprises a hard support layer such as a rock layer or a gravel layer in the ground to be improved.
Alternatively, the present invention relates to a soil improvement method capable of easily fixing a hardened pillar to the top of an existing underground structure and fixing the hardened pillar to the bottom of a submersible box, and an apparatus used therefor.

[0002]

2. Description of the Related Art Conventionally, as a ground improvement method for supporting and preventing settlement, a ground improvement method having high reliability is generally employed. The method of solidifying the ground can be roughly classified into the mechanical stirring method of stirring with machine blades and the cutting with high pressure jet,
Stirring is classified into two types: high-pressure injection stirring method.

In order to fix the hardened column on the hard supporting ground by the mechanical stirring method, it is necessary to take time from the top excavation bit to the lower stirring blade. However, in this case, excavation is often impossible. As a countermeasure, the above-described process is performed after the hard support ground is loosened by the preceding drilling machine.

[0004] In the high-pressure injection stirring method, the hardening material injection port is located at a position of about 10 cm from the front end, and an overhang is required similarly to the above-mentioned method. Further, when there is an existing structure constructed of concrete or the like in the ground to be improved, it is impossible to fix the structure to the existing structure by both methods.

[0005]

In order to fix a hardened column to a hard supporting ground for the purpose of supporting a structure or preventing settlement by a mechanical stirring method, which is one of the ground improvement methods for strengthening the ground described above. In addition, the hard support ground needs an overhang by the length of the tip head, and the overhang requires a large amount of labor.

Further, when a structure constructed of concrete or the like is buried in the ground to be improved, it is difficult to reliably fix the hardened pillar to the top end of the buried structure by obstructing the head. It is not possible with the device. Further, there is a problem that the hardened column cannot be fixed securely to the concrete bottom such as a submersible box.

In the high-pressure injection stirring method, a hardening material is injected at a high pressure from the vicinity of the tip of the injection rod to form a hardened column. The injection port of the hardening material is provided at a position about 10 cm from the tip of the rod. Therefore, in order to fix the hardened pillars on the hard support ground, it is necessary to have an overhang of the hard support ground up to the injection port as in the mechanical stirring method.

Further, it is not possible to fix the hardened pillar to the existing structure without drilling the existing structure to the injection port (about 10 cm).

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a ground improvement method for forming a hardened column above a hard supporting ground, in which a stirring blade is inclined downward at a lower portion of an injection rod. Attach the stirring rod, penetrate the injection rod into the hard support ground of the ground to be improved,
Without performing overburden of the hard support ground by the tip excavation bit of the injection rod, pulling up the injection rod while injecting a high-pressure hardening material onto the hard support ground from the tip nozzle of the stirring blade provided downwardly inclined, This is a ground improvement method that can fix and form a hardened pillar on a hard supporting ground.

[0010] The present invention relates to an injection molding method for fixing a hardened column to a hard supporting ground, for example, a rock layer or a gravel layer, a top of an existing underground structure constructed of concrete, and a concrete bottom of a submersible box. Stirring blades installed at the lower part of the rod are provided inclined downward, the injection rod penetrates to the hard support ground of the ground to be improved, and without excavating the hard support ground by the excavation head at the tip of the injection rod. It is possible to form a hardened column on the hard support ground by injecting a high-pressure hardening material onto the hard support ground from the tip nozzle of the stirring blade provided inclined downward and rotating the injection rod at a high speed to pull up the hardened column on the hard support ground. It is a ground improvement method that can be used.

Further, in a ground improvement method for forming a hardened column above the hard supporting ground, a stirring head formed by downwardly projecting a stirring blade below a pouring rod is attached.
The injection rod penetrates into the hard support ground of the ground to be improved, and is provided at the tip of a stirring blade formed by obliquely projecting the stirring head downward without performing overburden of the hard support ground by the tip drill bit of the injection rod. The high-pressure injection nozzle combined with the hardened material slurry and compressed air on the hard support ground was injected at high speed while high-pressure injection combined with the high-pressure injection nozzle to discharge almost the same amount of soil and mud as the injection amount. This is a ground improvement method that allows a pillar to be fixedly formed on a hard supporting ground.

An improvement device used in the above-mentioned ground improvement method is as follows:
A stirring blade of a stirring head attached to a lower part of an injection rod supported by a column and connected to a vertically movable rotary driving device is provided so as to project obliquely downward with respect to a shaft of the injection rod, and the stirring blade is provided. Is a ground improvement device provided with a hardening material injection nozzle at the tip of the base material.

[0013] Further, the present invention is a ground improvement device in which a stirring blade of a stirring head is provided to be inclined downward by 10 ° to 20 ° with respect to a shaft of an injection rod.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described based on examples. FIG. 1 is a side view of a ground improvement apparatus used in the ground improvement method of the present invention. The ground improvement device 10 has the stirring blade 3 of the stirring head 2 attached to the lower portion of the injection rod 1 supported by the column 8 and connected to the rotary drive device 9 that can move up and down. It is provided to be inclined and protruded. The stirring blade 3 which is inclined downward and protrudes with respect to the shaft body 1a of the injection rod 1 has a tip nozzle 4 for injecting a high-pressure hardening material 6 at the tip. Also,
The tip of the injection rod 1 has a drill bit 5.

The inclination angle of the stirring blade 3, which extends downward from the shaft body 1a of the injection rod 1, ranges from 10 ° to 20 °.
It is preferable to set the angle of the hardening column 7 formed by the hardening material 6 high-pressure jetted from the tip nozzle 4 of the stirring blade 3 to the hard supporting ground if the inclination angle is large. It becomes a small-sized hardened column, and if the angle is small, a large-sized hardened column similar to a stirring blade stretched horizontally with respect to the axis of the conventional injection rod can be formed, The fixation of the hardened column is weakened.

FIG. 2 is a cross-sectional view of a method of fixing a hardened column in a soft ground above a hard supporting ground using the apparatus 10 of the present invention. The injection rod 1 penetrates into the hard support ground 12 composed of a rock layer and a gravel layer in the soft ground 11 to be improved, and the stirring blade is used without excavating the hard support ground 12 by the tip drill bit 5 of the injection rod 1. The injection rod 1 is rotated and pulled up while rotating the injection rod 1 while injecting the hardening material 6 onto the upper surface of the hard support ground 12 from the tip nozzle 4 of 3 to form and improve the hardened column 7 in the soft ground 11 to be improved.

Further, the shaft body 1a of the injection rod 1 is
The injection rod 1 provided with the stirring head 2 having the tip nozzle of the stirring blade 3 having a downward angle of 20 ° to 20 ° as the high-pressure injection nozzle 4 penetrates into the hard supporting ground 12 of the ground 11 to be improved. The hard material is hardened on the hard support ground 12 from the high-pressure injection nozzle 4 provided at the tip of the stirring blade 3 which is inclined and protruded downwardly without stirring the hard support ground 12 by the tip drill bit. The injection rod is pulled up at high speed while ejecting the slurry and compressed air at a high pressure, and the same amount of mud is discharged as the injection amount, and a large-diameter hardened column is hardened into the ground without displacing the periphery. An anchor can be formed on the supporting ground.

FIG. 3 is a sectional view showing an improvement method using the apparatus of the present invention when an underground structure such as a subway is constructed in the ground to be improved. In order to improve the structure 13 constructed in the soft ground to be improved below the top 13 a of the underground structure 13, the injection rod 1 is used.
Then, when the hardening material 6 is injected at a high pressure from the tip nozzle 4 of the stirring blade 3, the hardening material 6 is blown to the top end 13a of the underground structure 13 because the stirring blade 3 is inclined and protrudes downward. By squeezing the hardening material 6 from the agitating blade 3 together with the compressed air and injecting it at high pressure and rotating the injection rod 1 at a high speed, the hardened material 6 is reliably supported by the top end 13a of the underground structure 13 and the hardened column 7 is improved. It can be formed in the planned soft ground 11.

FIG. 5 is a cross-sectional view showing a method of forming a hardened column using the apparatus of the present invention in the void space of the submersible box 14 buried in the quay wall, seawall or soft soil. Cavity room 14 of submersible box 14
a of the injection rod 1 and the tip bit 5 of the injection rod 1
When the material reaches the bottom plate 14b of the latent box 14, the hardening material 6 is ejected from the stirring blade 3 at a high pressure, and the hardening material 6 is fixed on the bottom plate 14b of the latent box 14 and the injection rod 1 is rotated upward to raise the gap chamber 14a.
The hardened pillars 7 are formed therein, and by repeating this operation sequentially, hardened pillars 7 as shown in FIG. 5 are formed. In the drawing, reference numeral 14c denotes a partition.

It is needless to say that the form of this application is not limited to the above embodiment. For example, the mounting angle of the injection rod and the stirring blade, the injection of only the hardening material, and the like can be changed in various modes. It is.

[0021]

According to the present invention, when a soft soil for the purpose of supporting and preventing settlement is hardened and improved, the underground supporting ground of the ground to be improved is a hardened supporting layer such as a rock layer and a gravel layer.
Alternatively, when there is an existing structure constructed of concrete or the like in the ground of the ground to be improved, or because the hard ground cannot be excavated by the bottom of a submersible box, etc., the hardened column cannot be securely fixed on the ground. Without hardening the hard support ground, it is possible to reliably fix the hardened pillar on the hard support ground, so that the existing structure is not drilled, that is, the structure is damaged. The cured column can be fixed without any trouble.

Further, the ground improvement method of the present invention is a method for improving a ground where there is a risk of insufficient supporting capacity and settlement, in which the tip of the stirring blade has a downward angle of 10 ° to 20 ° with respect to the shaft of the injection rod. Therefore, the hardening column can be fixed on the supporting ground or the existing structure without leaving the soft ground on the supporting ground by injecting the hardening material slurry and compressed air together with high pressure, and the structure Supports and prevents settlement.

[Brief description of the drawings]

FIG. 1 is a side view of a ground improvement device used in the ground improvement method of the present invention.

FIG. 2 is a cross-sectional view showing a state where a hardened pillar is fixed on a hardened supporting ground by the ground improvement method of the present invention.

FIG. 3 is a cross-sectional view showing a state where a hardened pillar is fixed to the top end of an existing underground structure by the ground improvement method of the present invention.

FIG. 4 is a sectional view showing a state in which a hardened column is fixed to a concrete bottom of a submersible box by the ground improvement method of the present invention.

FIG. 5 is a plan view showing a state in which a hardened column is fixed to the concrete bottom of the submersible box by the ground improvement method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injection rod 1a Shaft 2 Stirring head 3 Stirring blade 4 Tip nozzle 5 Tip drilling bit 6 Hardening material 7 Hardened column 8 Support 9 Rotation drive device 10 Improvement device 11 Soft ground 12 Hard ground such as rock layer 13 Underground structure 13a Top end 14 Submersible box 14a Void chamber 14b Bottom plate 14c Partition wall

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Eiji Sato, Inventor 2-17-4 Yanagibashi, Taito-ku, Tokyo Inside Onoda Chemiko Co., Ltd. (72) Asami Matsuda 2--17-4, Yanagibashi, Taito-ku, Tokyo Onoda F term in Chemiko Co., Ltd. (reference) 2D040 AA00 AB03 AC01 AC03 AC05 BA02 BA08 BB03 BC01 BD05 CB03 DA11 DB07 EA16 EA21

Claims (4)

[Claims] In a ground improvement method for forming a hardened column above a hard supporting ground, a stirring head formed by downwardly projecting a stirring blade at a lower portion of an injection rod is attached, and the injection rod is hardened on the ground to be improved. The hardening material penetrates to the support ground, and the hardening material is pressurized onto the hard support ground from the tip nozzle of the stirring blade, which is inclined downward and protrudes downward without stirring the hard support ground by the excavation bit of the injection rod. A ground improvement method capable of fixing a hardened pillar to a hard support ground, wherein the injection rod is pulled up while being sprayed, and a hardened pillar is fixedly formed on the hard support ground. 2. A ground improvement method for forming a hardened column above a hard supporting ground, wherein a stirring head formed by projecting a stirring blade downward and inclined downward is mounted on a lower portion of an injection rod, and the injection rod is hardened on the ground to be improved. It penetrates to the support ground, and does not carry out the overburden of the hard support ground by the excavation bit of the injection rod. At the same time, the injection rod is pulled up at high speed while ejecting the hardening material slurry and the compressed air at high pressure, discharging the same amount of mud as the injection amount. A ground improvement method capable of fixing hardened pillars to hard supporting ground, characterized by fixing hardened pillars having a diameter. 3. A stirring blade of a stirring head mounted on a lower part of an injection rod supported by a column and connected to a rotatable driving device capable of moving up and down, is provided so as to project obliquely downward with respect to the shaft of the injection rod. And a hardening material injection nozzle provided at a tip of the stirring blade. 4. The ground improvement apparatus according to claim 3, wherein the stirring blade of the stirring head is provided to be inclined downward by 10 ° to 20 ° with respect to the shaft of the injection rod.