JP3961510B2 - Ground injection method - Google Patents

Description

  The present invention relates to ground injection methods such as soft ground, leaky ground, ground that may be liquefied, contaminated ground, etc., in particular, support ground under existing structures that are difficult to perform ground injection, bottom of waste disposal site or In particular, it is related to ground injection methods such as below reservoirs and reservoirs, and more specifically, the support ground under existing structures where it is difficult to inject ground can be injected quickly, reliably and economically. The present invention relates to a ground injection method capable of preventing liquefaction of the ground in advance, further preventing elution of harmful substances from a waste disposal site, and further preventing leakage from a reservoir or a reservoir.

  In liquefaction countermeasures for building foundations, conventionally, an outer injection pipe having a plurality of discharge ports by boring in the horizontal direction is installed under the building foundation, and the outer injection pipe is inserted into the outer pipe. A method of injecting an injection solution into the ground sequentially from the discharge port and solidifying the ground is used.

  Since the liquefaction prevention work is a ground improvement for large-capacity soil, it is necessary to economically and reliably improve the ground. For this purpose, the injection must be performed between soil particles at a low discharge rate. In this case, it takes a long time to improve the ground, and the construction period becomes longer, which increases the construction cost. In order to prevent this, by simultaneously injecting from a plurality of outlets, it is possible to inject at a high discharge speed as a whole while injecting from one outlet at a low discharge speed to improve economic efficiency. It is possible.

However, if the outer injection pipe is installed in the horizontal direction, the cross section of the outer injection pipe is easily deformed by the earth pressure from above, and the axial direction of the injection pipe is also easily deformed, making it difficult to insert and move the inner injection pipe. Become. In particular, when a plurality of discharge ports are provided in the axial direction of the inner tube, there is a problem that the injection portion at the tip of the inner tube becomes long and is easily affected by the deformation of the outer tube.
Japanese Patent Application Laid-Open No. 2003-346885 Japanese Patent Laid-Open No. 2003-261934

  The present inventor solves the problem of deformation of the injection pipe in the ground injection method for improving the foundation foundation ground in the horizontal direction, such as the liquefaction countermeasure work for the building foundation, and discharges the injection liquid to a plurality of selected injection pipes. It has been found that it is possible to perform optimal injection penetration at the same time from the outlet and in accordance with the injection situation at each discharge port, thereby forming a predetermined-shaped solid body economically and reliably at a predetermined position. It came to complete.

  Therefore, the object of the present invention is to rapidly consolidate into a certain shape by injecting from an infusion tube installed in a horizontal direction, such as infusion for liquefaction measures to consolidate the ground below the building. By simultaneously injecting the injection solution from the outer tube outlets installed at a plurality of selected injection points, it is possible to achieve uniform infiltration and consolidation at a predetermined position and in a predetermined shape. In addition, an object of the present invention is to provide a ground injection method that can be applied in a short period of time and can improve the shortcomings of the above-mentioned known techniques.

  In order to achieve the above-mentioned object of the present invention, according to the present invention, a boring hole obtained by bending into the ground from the vicinity of the ground to be improved or by arbitrarily combining bending and straight lines is obtained. An outer tube having a plurality of outer tube discharge ports equipped with check valves is installed therein, and three or more expansion / contraction packers are provided in the outer tube at intervals in the longitudinal direction of the outer tube, and are adjacent to each other. An infusate flow path in which the space between the contraction packers is a discharge position and the inner tube discharge port is located at a separate discharge position, and a packer flow path that is inflated by sending a fluid to the expansion / contraction packer or contracting by discharge Each of the inner pipes independently formed inside is movably inserted, and after the discharge position is matched with the outer pipe discharge port, a fluid is sent to the three or more expansion / contraction packers through a packer channel. Inflating the expansion / contraction packer, thereby adjoining each other The tube space is formed in the gap sandwiched by condensation packer, the injectate from the inner tube the discharge port via the pipe space and the outer tube discharge port, characterized in that injecting the ground.

  Furthermore, in order to achieve the above-described object, according to the present invention, the boring hole obtained by bending into the ground from the ground surface near the ground to be improved or by arbitrarily combining the bending and the straight line is obtained. In the outer longitudinal direction, three or more outer pipe packers are fitted with a space therebetween, and an outer pipe having an outer pipe discharge port is installed between adjacent outer pipe packers. Three or more expansion / contraction packers are provided at an interval, and a discharge position is defined between adjacent expansion / contraction packers, and fluid is sent to the injection liquid flow path where the inner tube discharge port is located at this discharge position and the expansion / contraction packer. The inner tube formed independently of each other with the packer flow path to be expanded or discharged and contracted is movably inserted, and a fluid is sent to the three or more expansion / contraction packers to remove the expansion / contraction packers. After inflating, then between outer tube packers Characterized by injecting an infusion liquid into the ground from the outer tube discharge opening through the inner tube outlet of injection liquid flow path.

  Furthermore, in order to achieve the above-described object, according to the present invention, a plurality of bores obtained by bending into the ground from the vicinity of the ground to be improved, or by arbitrarily combining bending and straight lines, are obtained. An outer tube having a plurality of outer tube discharge ports equipped with check valves is installed in the bore hole, and three or more expansion / contraction packers are provided in the outer tube in the longitudinal direction at intervals, adjacent to each other. A plurality of infusion flow paths in which the expansion / contraction packer is a discharge position and the inner tube discharge port is positioned at a separate discharge position, and a packer that sends the fluid to the expansion / contraction packer for expansion or discharge and contraction An inner pipe formed independently of each of the flow paths is movably inserted, and the discharge position is matched with the outer pipe discharge port, and then the fluid is passed through the packer flow path to the three or more expansion / contraction packers. To expand the expansion / contraction packer, Forming a space in the pipe between the adjacent expansion and contraction packers, and injecting the injection liquid from the injection liquid feeding device through the inner pipe discharge port to the ground through the pipe internal space and the outer pipe discharge port, The injection liquid feeding device is connected to the control unit, the injection liquid tank, the injection liquid tank, pressurizing and feeding the injection liquid, an injection liquid pressurizing part, and the pressurized injection liquid in the ground A liquid feeding pipe for feeding to each injection pipe, the injection liquid pressurizing section and the liquid feeding pipe are connected to a control section, and under the control of the control section, the injection liquid is ground into the ground from the plurality of outer pipe discharge ports. It is characterized by being injected simultaneously.

  The above outer pipe is installed in the ground by the following step (a), (b) or (c).

(A) Insert a boring rod fitted with a drill head at the tip into the casing, and bend into the ground from the ground surface near the ground to be improved while rotating the drill head, or push in a combination of bending and straight lines. After boring and the boring hole reaches a predetermined position, pull out the boring rod, insert the outer pipe having a plurality of outer pipe discharge ports with check valves into the remaining casing, pull out the casing, and Is installed in the ground.

(B) From the ground surface in the vicinity of the ground to be improved, push the casing into the ground while rotating the casing, bend it, or drill it in any combination of bending and straight lines. An outer pipe having a plurality of outer pipe discharge ports provided with stop valves is inserted, the casing is pulled out, and the outer pipe is installed on the ground.

(C) Insert a boring rod with a drill head attached to the tip from the ground surface near the ground to be improved into the outer tube and bend while rotating the drill head, or any combination of bending and straight lines Then, push it with the boring rod and boring, and after the boring hole reaches a predetermined position, pull out the boring rod and install the outer tube on the ground.

  The ground injection method according to the present invention is to bend to the ground to be improved, or to bend by arbitrarily combining bending and straight lines, and an outer pipe having a plurality of outer pipe discharge ports is installed in the obtained borehole. In this outer tube, three or more expansion / contraction packers are fitted in the outer longitudinal direction with an interval between them, and the expansion / contraction packer adjacent to each other is set as a discharge position, and the inner tube discharge port is positioned at a separate discharge position. An inner pipe formed independently of the injection liquid flow path and the packer flow path for inflating the fluid by sending it to the expansion / contraction packer or discharging and contracting it is movably inserted therein, thereby the discharge port Since the injection solution is injected into the ground from the ground, the support ground under the existing structure, which is difficult to be injected into the ground, is quickly and reliably and economically injected into the ground, resulting in ground subsidence and liquefaction of the ground during an earthquake. Can be prevented in advance, Et to obtain preventing elution of hazardous substances from waste sites may prevent water leakage from the addition pond and reservoirs.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a partial sectional view showing an outer tube and an inner tube of an injection tube according to the present invention inserted into the ground. FIG. 2 is a cross-sectional view of the injection tube used in the actual construction of the injection tube shown in FIG. FIG. 3 is a cross-sectional view of an outer tube having three or more outer tube packers installed in the ground. 4 is a cross-sectional view of the outer tube of FIG. 3 with the inner tube according to the present invention inserted therein. FIG. 5 is a basic schematic diagram of the ground treatment to be improved directly under the structure. FIG. 6 is a basic schematic diagram of the ground treatment to be improved directly under the structure.

  First, as shown in FIG. 5, the ground 1 is bent from the ground surface 2 near the ground 1a to be improved directly under the immovable structure 21 such as a building, a waste disposal site, a reservoir, a reservoir, or the like. Or a combination of a bend and a straight line, for example, in FIG. 5, first bend obliquely, then straight to the ground 1a to be improved immediately below the structure 21, and then bend obliquely. Then, a hole is drilled to the near ground surface 2 on the opposite side to form a boring hole 3.

  FIG. 6 shows an example in which a conventional vertical hole 22 and an oblique straight hole 23 are used together with a curved (bent) boring hole 3. In this method, since the boring hole 3 of the present invention is further used in combination with the conventional technique, the ground 1a to be improved is consolidated more reliably and rapidly to form a consolidated region 24.

  In the present invention, the outer tube 7 is installed in the bore hole 3 thus obtained as shown in FIG. 1, and the inner tube 13 is movably inserted into the outer tube 7 to insert the injection tube A into the ground. 1 to form. The outer tube 7 has a plurality of outer tube discharge ports 5 each having a rubber sleeve 4 as a check valve. Further, the inner tube 13 is fitted with three or more expansion / contraction packers 8 in the outer longitudinal direction with an interval between them, and a space between the expansion / contraction packers 8, 8 adjacent to each other is set as a discharge position 9. An infusate flow path 11 located at different discharge positions 9 and a packer flow path 12 for inflating the fluid through the inlet / outlet port 12a to the expansion / contraction packer 8 or discharging and contracting are formed independently inside. It is constituted by.

  The injection pipe A having the above-described configuration sends the fluid such as water and air from the inlet / outlet port 12a to the three or more expansion / contraction packers 8 through the packer channel 12 after the discharge position 9 is matched with the outer pipe discharge port 5. The expansion / contraction packer 8 is inflated, thereby forming a pipe inner space 15 in a gap 14 sandwiched between the expansion / contraction packers 8 adjacent to each other, and an injecting liquid is passed from the inner pipe discharge port 10 through the pipe inner space 15 and the outer pipe discharge port 5. Inject into the ground 1. The injection solution is sent from the injection solution tank 35 to the injection solution channel 11 of the inner tube 13 through the pumps 36 and 36 using the automatically controlled injection solution delivery device X. F is a flow meter and P is a pressure gauge. The injection liquid feeding device X will be described later.

  Next, the above-described injection tube A discharges the fluid from the expansion / contraction packer 8 to contract the expansion / contraction packer 8, moves the inner tube 13 to match the discharge position 9 with the other outer tube discharge port 5, and the injection stage. After the movement, the expansion / contraction packer 8 is expanded to form a space 15 in the pipe, and the injection solution is repeatedly injected into the ground 1 in the same manner as described above.

  The above-mentioned injection pipe A may fill the space 17 between the outer wall 6 of the outer pipe 7 and the drilling wall 16 with the seal grout 18 and inject the injected liquid into the ground 1 by breaking the seal grout 18. it can. Further, at least the tip portion 13a of the inner tube 13 is made of a hard material such as metal or hard plastic and is integrally formed. Moreover, the integrated tip portion 13a is partially formed by a bending member 19 such as a hose. Since the injection pipe A according to the present invention is inserted laterally in the ground 1, the inner pipe 13 may be deformed by earth pressure from above. Even in this case, since the distal end portion 13a of the inner tube 13 is integrally formed of a hard material and is partially formed by the bending member 19, both the injection liquid channel 11 and the packer channel 12 follow deformation. And can be smoothly used for injection.

  FIG. 2 is a cross-sectional view showing an actual injection tube actually used at the site of the injection tube shown in FIG. 1, and in particular, the distal end portion 13 a is connected by a flexible member 19 such as a rubber tube. In the case of this injection tube, as in FIG. 1, the injection solution is sent from the injection solution tank 35 to the injection solution channel 11 of the inner tube 13 via the pump 36 using the automatically controlled injection solution delivery device X. .

  FIG. 3 is a cross-sectional view of a state in which the outer tube 7 having three or more outer tube packers 20 is installed in the ground 1. For the installation of the outer tube 7, first, after drilling the boring hole 3, the outer tube 7 is inserted into the boring hole 3 without expanding the outer tube packer 20 (not shown). Next, although not shown, a fluid such as water or air is introduced into the outer tube packer 20 to be expanded, and an inner tube for forming the outer tube packer 20 is inserted into the outer tube 7 as shown in FIG. The outer tube 7 is installed in the bore hole 3 of the ground 1. An outer pipe discharge port 5 is provided between the outer pipe packers 20 and 20 of the outer pipe 7.

  FIG. 4 shows another embodiment of the injection tube A according to the present invention obtained by movably inserting the inner tube 13 into the outer tube 7 installed on the ground 1. As in FIG. 1, the inner tube 13 is provided with a plurality of expansion / contraction packers 8 at intervals in the outer longitudinal direction, and a space between adjacent expansion / contraction packers 8 is set as a discharge position 9. An infusion solution flow path 11 in which 10 is located and a packer flow path 12 that is inflated by sending a fluid to the expansion / contraction packer 8 from an inlet / outlet 12a or discharged and contracted are formed independently. Then, the fluid is sent to the three or more expansion / contraction packers 8 to expand the expansion / contraction packers, and then the inner tube discharge of the injection liquid channel 11 from the outer tube discharge port 5 between the outer tube packers 20, 20. An injection solution is injected into the ground 1 through the outlet 10.

  In the case of the injection tube A of FIG. 4 as well, the fluid is discharged from the expansion / contraction packer 8 to contract the expansion / contraction packer 8, and the inner tube 13 is moved to move the discharge position 9 to another outer tube discharge port. 5 and the injection stage is moved, the expansion / contraction packer 8 is expanded, and the injection solution is repeatedly injected into the ground 1 in the same manner. The tip portion 13a of the inner tube 13 is also integrally formed of a hard material as in FIG. 1, and the tip portion 13a is also partially formed of a deflecting member 19.

  When the above-described injection pipe A is inserted into the ground 1, first, the outer pipe 7 is first embedded in the ground 1 as shown in FIG. 7, which will be described with reference to FIG. 7. A pile 25 is formed and a boring machine 26 is installed. Next, a boring rod 28 having a drill head 27 at the tip is pushed into the ground 1a to be improved while rotating the drill head 27 from the boring machine 26 on the nearby ground surface 2 through the starting pile 25, and drilled. At this time, the boring rod 28 is drilled while being inserted into the casing 29. When bending the drilling hole, although not shown, the drilling is continued by adjusting the tip taper blade of the drill head 27 in the bending direction. This drilling may be performed until reaching the near ground surface 2 on the opposite side, but as shown in FIG. 7, it is sufficient to perform the drilling to the end of the ground 1a to be improved.

  Subsequently, the boring rod 28 is pulled out to leave only the casing 29 in the ground 1. At this time, the drilling hole (boring hole 3) is protected by the casing 29. Furthermore, although not shown in the casing 29, the outer tube 7 having a plurality of outer tube discharge ports 5, 5,... A space 17 between the outer wall 6 and the drilling wall 16 is filled with a seal grout 18, and the outer tube 7 is installed in the ground as shown in FIG. 3 and 4, when the outer tube 7 includes the outer tube packer 20, the outer tube packer 20 is expanded into the boring hole 3 after the casing 29 is pulled out. After that, the outer tube packer 20 is expanded and the outer tube 7 is installed in the ground 1. The seal grout 18 is not used.

  Further, the outer pipe 7 described above will be described with reference to FIG. 7. From the ground surface 2 in the vicinity of the ground 1a to be improved, the casing 29 is pushed into the ground 1 while rotating and bent, or the bending and straight lines are arbitrarily selected. The outer pipe 7 having a plurality of outer pipe discharge ports 5, 5... 5 provided with check valves is inserted into the casing 29 of the obtained bore hole 3, and the seal grout 18 is The casing 29 may be pulled out while being filled, and the outer tube 7 may be sealed with the seal grout 18 and installed on the ground 1 as shown in FIG.

  Furthermore, the outer pipe 7 is bent while rotating the outer pipe 7 itself from the ground surface 2 in the vicinity of the ground 1a to be improved into the ground 1, or is pushed together with the boring rod 28 in any combination of bending and straight lines. Then, after the boring hole 3 reaches a predetermined position, the boring rod 28 is pulled out and the outer tube 7 is installed on the ground 1 as shown in FIG.

  FIG. 8 is an explanatory view of the ground injection method according to the present invention using the injection liquid feeding device X. In FIG. 8, similarly to the above, the ground 1 of the ground 1 is bent diagonally downward from the ground surface 2 and then the bored hole 3 is drilled in the horizontal direction. An outer pipe 7 having a plurality of outer pipe discharge ports 5, 5... 5 provided with a check valve 4 as shown in FIG. 1 is installed in the boring hole 3. As shown in FIG. 5, three or more expansion / contraction packers 8, 8... 8 are provided at intervals in the outer longitudinal direction, and the discharge positions 9 are provided between the expansion / contraction packers 8, 8 adjacent to each other. A plurality of injection liquid flow paths 11 in which the discharge ports 10 are located at different discharge positions 9 and a packer flow path 12 for supplying fluid to the expansion / contraction packer 8 to expand or discharge and contract are independently provided. The inner tube 13 formed in this manner is movably inserted, the discharge position 9 is made to coincide with the outer tube discharge port 5, and then the fluid is passed through the packer channel 12 to three or more expansion / contraction packers 8, 8. To inflate the expansion / contraction packer 8, thereby being sandwiched between the expansion / contraction packers 8, 8 adjacent to each other. The tube space 15 is formed between 14 come from the infusate liquid feeder X through the pipe space 15 and the outer tube discharge port 5 is injected into the ground 1 of the infusate through the inner tube the discharge port 10. In FIG. 8, detailed description of the outer tube 7 and the inner tube 13 is omitted, and a state in which the inner tube 13 is movably inserted into the outer tube 7 is represented as an injection tube A.

  The infusion solution delivery apparatus X shown in FIG. 8 includes a control unit 30, an infusion solution pressurizing unit 31, an infusion solution distribution unit 32, an infusion unit 33, and a solution delivery system 34. When the operation is performed manually, the control unit 30 is not necessary. Hereinafter, an example using the control unit 30 will be specifically described in detail.

  As shown in FIG. 8, the infusate pressurizing unit 31 pressurizes the infusate from the infusate tank 35 by a pump 36 (grout pump), and the infusate distribution unit via the liquid feed system 34 as a pressurized infusate. 32. The grout pump 36 receives an instruction from the injection monitoring board 30a of the control unit 30 and pressurizes the injected liquid to a desired pressure.

  The injection solution distribution unit 32 includes a plurality of branch pipes 37, 37. Each of these branch pipes 37, 37... 37 has a connecting portion 38 connected to the injection pipe A at the tip. The connecting portion 38 can replace the branch pipe 37 with another injection pipe A when the predetermined injection amount is injected through the predetermined injection pipe A or when the predetermined injection pressure is reached. .

  As shown in FIG. 8, the branch pipes 37, 37... 37 described above are arranged to extend from the distributor 39 connected to the pressurizer 31 via the liquid feeding system 34, and are connected at the tip. The portion 38 is connected to the injection tube A. And the pressurization injection liquid from the pressurization part 31 is distributed to each branch pipe 37, 37 ... 37 via the distribution container 39, and is sent to the injection pipe A. The distribution container 39 can be provided with a stirring device (not shown). Moreover, each branch pipe 37, 37 ... 37 can also be connected with the liquid feeding system 34 from the pressurization part 31 immediately after not passing through the distribution container 39. FIG.

Further, in FIG. 8, the flow rate of the liquid flow meter 40 can be grasped by measuring the total amount of the branch flow meters f _1, f ₂ ... F _i, f _n. 40 is not necessarily required. Further, the liquid feeding pressure gauge 41 is not necessarily provided in the liquid feeding system 34 but may be provided in the distribution container 39 immediately after. V _{1 to} V ₄ are branch valves, P _{1 to} P ₄ are branch pressure gauges, 30 b is an operation panel 30 c is an injection recording board, 30 d is a data input device, and 42 is a liquid feed valve. Reference numeral 43 denotes a pressure cylinder for sending fluid to the expansion / contraction packer 8, and 44 denotes an inner pipe automatic elevator, both of which are connected to the control unit 30 and operate in response to an instruction from the control unit 30.

  FIG. 9 is an explanatory view of a ground injection method according to the present invention using a multi-injection injection device as an injection solution feeding device, and an injection solution tank 35 for storing the injection solution and an independent motor or the like in each plant. Although not shown in the drawing, the unit pumps 46, 46... 46 operated by a common drive source 45 and connected to the control unit 30 are controlled, and these unit pumps 46, 46. The liquid supply pipes 47, 47,... A connecting portion 38 is provided at the tip of each liquid feeding pipe 47, 47... 47, and is connected to the injection liquid flow path 11 of the inner pipe 13 (not shown) of the injection pipe A inserted into the boring hole 3 of the ground 1. The injection liquid in the injection liquid tank 35 is pumped to the injection liquid flow path 11 of each injection pipe A at an arbitrary injection speed, injection pressure or injection volume by the operation of each unit pump 46, 46. The rubber sleeve 4 is pushed open from the tube discharge ports 5, 5. V is a branch valve. The pressure cylinder 43 and the automatic elevator 44 operate in response to an instruction from the control unit 30 as in FIG.

  The injection method according to the present invention is particularly suitable for processing under a structure such as a building. For example, a plurality of layers can be laminated in the depth direction below the structure 21 as shown in FIG. 10, or, further, as shown in the plan view of FIG. Can be set in parallel, or can be set in the depth direction as shown in FIG. 11 to form a plurality of layers.

  The present invention, together with the method of simultaneously injecting the behavior of seepage of FIG. 12 from a plurality of outlets, injects an injection solution from an injection solution pressurizing unit through a plurality of injection solution feeding systems to the injection point in the ground, A plurality of infusion solution delivery systems are provided with flow rate pressure detectors, and the infusion solution flow rate and / or pressure data detected from these detectors is transmitted to a centralized control device equipped with an infusion monitoring panel for infusion solution delivery. The injection status from the liquid system is displayed on the screen of the injection monitoring panel, and while performing batch monitoring, injection is performed simultaneously from a plurality of selected injection points, and each injection status is determined by checking the status of each injection. Since the process from the start to the end can be performed separately and the entire injection control can be performed, the predetermined place is determined based on the behavior of the injection solution in FIGS. The possible formation caking body shape.

  Boreholes of arbitrary shape were drilled in the place to be improved on the ground, and the injection solution was simultaneously injected into the ground through the multiple discharge ports from this borehole, so it was installed horizontally. Despite injection from the injection tube, it enables infiltration consolidation to a predetermined position in a predetermined infiltration solidification form, and the supporting ground below the existing structure, which is difficult to perform ground injection, can be rapidly and reliably spread over a wide area. It is an industrially useful invention that can be applied to ground improvement.

It is sectional drawing showing the basic structure for demonstrating the injection pipe concerning this invention. It is sectional drawing of the injection pipe used for actual construction. It is sectional drawing of the state which installed the outer pipe | tube which has three or more outer pipe | tube packers in the ground. It is sectional drawing of the state which inserted the inner tube concerning this invention in the outer tube | pipe of FIG. It is a basic schematic diagram of the ground treatment to be improved directly under the structure. It is another basic schematic diagram of the ground treatment to be improved directly under the structure. It is explanatory drawing showing the boring state below a structure. It is explanatory drawing for implementing this invention injection construction method using an injection liquid feeding apparatus. It is explanatory drawing for implementing this invention injection construction method using another injection liquid sending apparatus. It is a longitudinal cross-sectional view of the example of ground injection below the structure. It is explanatory drawing showing the state inject | poured and consolidated by the method of this invention. It is a top view of the example of ground injection below a structure.

Explanation of symbols

A Infusion tube X Infusion solution delivery system 1 Ground 1a Ground to be improved 2 Ground surface 3 Boring hole 4 Check valve (rubber sleeve)
DESCRIPTION OF SYMBOLS 5 Outer tube discharge port 6 Outer wall 7 Outer tube 8 Expansion / contraction packer 9 Discharge position 10 Inner tube discharge port 11 Injection liquid flow path 12 Packer flow path 12a Inlet / outlet 13 Inner pipe 13a Tip part 14 Clearance 15 Inner space 16 Hole hole 17 Space 18 Seal grout 19 Deflection member 20 Outer tube packer

Claims (8)

A ground injection method comprising a combination of the following steps (a) to (g).
(A) Bending from the ground surface in the vicinity of the ground to be improved into the ground, or by arbitrarily combining bending and straight lines.
(B) An outer tube having a plurality of outer tube discharge ports provided with check valves is installed in the obtained boring hole at intervals in the outer longitudinal direction .
(C) In this outer tube, three or more expansion / contraction packers are provided at intervals in the outer longitudinal direction, and an inner tube having an inner tube discharge position between adjacent expansion / contraction packers is movably inserted.
(D) Inside the inner pipe, a plurality of injection liquid flow paths having an inner pipe discharge port located at the inner pipe discharge position, and a fluid is sent to the expansion / contraction packer to be expanded or discharged to be contracted. The packer flow paths are formed independently of each other.
(E) After the inner tube discharge position is matched with the outer tube discharge port, fluid is sent to the three or more expansion / contraction packers through the packer flow path to expand the expansion / contraction packers.
(F) As a result, a plurality of in-pipe spaces are formed in the gaps sandwiched between the expansion / contraction packs adjacent to each other.
(G) The injection solution is injected from the plurality of inner tube discharge ports into the ground via the respective tube inner space and the outer tube discharge port. And discharging the fluid to contract the inflation and deflation packer from deflating the packer, the discharge position by moving the inner tube is matched to the other outer tube discharge port, the injection stage after the movement, by expanding the expansion and contraction packer The ground injection method according to claim 1, wherein a space in the pipe is formed and the injection solution is repeatedly injected into the ground in the same manner.   The ground injection method according to claim 1, wherein at least a tip portion of the inner pipe into which the injection liquid channel and the packer channel are inserted is formed of a hard material.   The ground injection method according to claim 3, wherein the inner tube tip portion integrated with the hard material is partially formed of a flexible member. A ground injection method comprising a combination of the following steps (a) to (g).
(A) Bending from the ground surface in the vicinity of the ground to be improved into the ground, or by arbitrarily combining bending and straight lines.
(B) In the obtained boring hole, three or more outer tube packers are fitted at intervals in the outer longitudinal direction, and an outer tube having an outer tube discharge port is installed between adjacent outer tube packers.
(C) In this outer tube, three or more expansion / contraction packers are provided at intervals in the outer longitudinal direction, and an inner tube having an inner tube discharge position between adjacent expansion / contraction packers is movably inserted.
(D) Inside the inner pipe, a plurality of injection liquid flow paths having an inner pipe discharge port located at the inner pipe discharge position, and a fluid is sent to the expansion / contraction packer to be expanded or discharged to be contracted. The packer flow paths are formed independently of each other.
(E) The inner tube discharge position is matched with the outer tube discharge port.
(F) Thereafter, a fluid is sent to the three or more expansion / contraction packers through the packer flow path to expand the expansion / contraction packers.
(G) Next, the injection solution is injected into the ground from the outer tube discharge port between the outer tube packers through the inner tube discharge port of the injection solution channel.   The fluid is discharged from the expansion / contraction packer, the expansion / contraction packer is contracted, the inner tube is moved, the discharge position is matched with the other outer tube discharge port, the injection stage is moved, the expansion / contraction packer is expanded, and the like The ground injection method according to claim 5, wherein the injection solution is repeatedly injected into the ground.   The ground injection method according to claim 5, wherein at least a tip portion of the inner pipe into which the injection liquid channel and the packer channel are inserted is formed of a hard material. The ground injection method according to claim 5, wherein the tip portion of the inner pipe integrated with the hard material is partially formed of a flexible member.

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