JP5055186B2 - Ground reinforcement method, ground reinforcement structure - Google Patents

Description

  The present invention relates to a method for reinforcing the ground by forming a hole by drilling the ground, inserting a bag into the hole, and filling the bag with grout, and a reinforcing structure constructed by this method.

  Conventionally, as a method for reinforcing the ground, there has been used a method in which a hole is formed by drilling the ground, a bag body is disposed in the hole, and a grout is filled in the bag body. In such a method, since the gap is generated in the hole after the ground is drilled until the grout in the bag is filled, the ground becomes unstable.

Therefore, for example, in Patent Document 1, a hole is formed by drilling the ground, a protective tube is disposed in the formed hole, a bag body is inserted into the protective tube, and grout is filled in the bag body. After that, a method for removing the protective tube is described. According to this method, while the protective tube is disposed in the hole, the ground is supported by the protective tube, and a stable state is maintained.
Japanese Patent Laid-Open No. 11-181752

  By the way, in the method described in Patent Document 1, if the bag body is completely filled with grout with the protective tube remaining in the hole, it is difficult to remove the protective tube between the ground and the bag body. End up. Therefore, the grout is filled to such an extent that the inner surface of the protective tube and the bag are not in close contact with each other, and after removing the protective tube, the grout is filled again. For this reason, a gap is formed between the bag body and the inner peripheral surface of the hole until the grout is filled again after removing the protective tube, and the ground becomes unstable during this period. End up.

  The present invention has been made in view of the above problems, and an object of the present invention is to reinforce the ground by filling a bag body inserted into a hole formed in the ground with a curable filler. To prevent the ground from becoming unstable.

  The ground reinforcement method of the present invention is a method of reinforcing the ground, wherein a protective tube having a throttle portion partially opened at one end is formed in the ground, and an outer peripheral surface of the protective tube includes an inner portion of the hole. A protective tube disposing step disposed in the hole so as to be in contact with the peripheral surface; a cylindrical bag body in which one end is closed and the other end is opened; and the one end is inside the protective tube through the throttle portion A bag body disposing step that is positioned so that the other end protrudes from the throttle portion to the outside of the protective tube, and pressurizing and filling a curable filler into the bag body from the opening, And a filling step of pushing out the protective tube toward the other end side of the through hole by a pressure of filling the material.

  In the ground reinforcement method, the bag body placement step is performed before the protection tube placement step, and the protection tube placement step places the protection tube in which the one end of the bag body is placed inside the hole. You may arrange in.

  The protective tube arranging step includes a drilling step for forming a small-diameter hole in the ground, and expanding the small-diameter hole by a diameter-enlarging means, and expanding the protective tube connected to the diameter-expanding means. It may consist of a diameter expanding step for drawing into the diameter hole.

  In the protective tube arranging step, the protective tube may be arranged in the hole so that the outer peripheral surface thereof is covered with the lubricating liquid. The lubricating liquid may be a cement / bentonite solution. In addition, as a method of arranging the protective tube in the hole so that the outer peripheral surface thereof is covered with the lubricating liquid, a method of applying the lubricating liquid to the outer peripheral surface of the protective tube in advance, or the diameter expanding means It is possible to use a method of discharging the lubricating liquid from

  In addition, after the filling step, a refilling step of pressurizing and filling the filling material into the bag body may be performed again. At this time, in the refilling step, the end portion reaches the leading end portion of the bag body. And you may fill the said filler using the injection pipe which opens in the multiple places in the said bag body.

Furthermore, in the filling step, the filling material may be filled using injection pipes that reach an end portion of the bag body and open at a plurality of locations in the bag body.
A roller may be provided on the edge of the throttle portion.
The ground reinforcing structure of the present invention is constructed by the above method.

  According to the present invention, the bag is filled with the filler, and the protective tube is pushed out of the hole by the pressure of filling the filler. Therefore, the bag is filled with the filler as soon as the protective tube is removed. It will be supported by the body and can prevent the ground from becoming unstable.

Hereinafter, the ground reinforcement method of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a vertical sectional view showing an example of a reinforcing structure 10 constructed by the ground reinforcing method of the present embodiment. In the example shown in the figure, the ground 100 is provided with a fill 50, and a track 51 is laid on the top of the fill 50 so as to extend in a direction perpendicular to the paper surface. The ground 100 is made of earth and sand having a relatively low supporting force such as soft ground. A plurality of holes 120 are excavated in the ground 100 side by side in the direction in which the track 51 extends. One end of each of the holes 120 opens to the ground surface, and the other end opens into a groove 110 provided along the line 51. Then, the ground reinforcing structure 10 inserts the bag body 20 into the holes 120, fills the bag body 20 with the grout 30 until the surface thereof is in close contact with the inner surface of the hole 120, and the filled grout 30 is cured. It is a thing. According to the ground reinforcing structure 10, the hardened grout 30 supports the ground 100, and the supporting force of the ground 100 can be improved. Note that a reinforcing member such as a core material may be appropriately embedded in the grout 30.

  The bag body 10 is a flexible member formed in a cylindrical shape with one end closed and the other end opened, and is made of hemp or synthetic fiber having flexibility and wear resistance, for example. A woven fabric or a nonwoven fabric in which reinforcing fibers having high tensile strength such as aramid yarn and carbon fiber are mixed can be used. Further, the bag body 10 is subjected to a watertight process so that moisture does not easily leak out, and when the grout 30 is filled with a low injection pressure (for example, 0.1 to 0.3 MPa), moisture is externally provided. When the grout 30 is filled at a high injection pressure (for example, 0.5 MPa) without oozing out, the water contained in the grout oozes out.

Hereinafter, the construction method of the ground reinforcement structure 10 will be described.
2 to 9 are vertical cross-sectional views for explaining a construction method of the ground reinforcing structure 10 of the present embodiment.
First, as shown in FIG. 2, a groove 110 is excavated on the side of the embankment 50 so as to extend along the embankment 50.

  Next, as shown in FIG. 3, the ground 100 is drilled with a drill bit 200 attached to the tip of the drill pipe 210 to form a small-diameter hole 120. In the drilling operation, the ground 100 is dug from the ground surface on the opposite side of the groove 110 across the embankment 50 with the drilling direction facing the lower side of the embankment 50, and after reaching the lower side of the embankment 50, the drilling direction is leveled. The direction is changed by digging until the hole 120 reaches the groove 110.

  When the hole 120 penetrates to the groove 110, the drill bit 200 attached to the tip of the drill pipe 210 is removed, and the reamer 220 is attached to the tip of the drill pipe 210 as shown in FIG. Further, a flexible protective tube 60 made of polyethylene or the like is connected to the rear part of the reamer 220, and the bag body 20 is disposed in advance in the protective tube 60 over its entire length.

  FIG. 10 is an enlarged view of the end of the protective tube 60 opposite to the side connected to the reamer 220, (A) is a vertical sectional view in the axial direction, and (B) is AA in (A). It is an arrow view. As shown in the drawing, the end of the protective tube 60 has a closing member 70 that is formed in a circular shape and has an edge portion 70 </ b> A that is erected along the outer periphery. It is attached by fitting. The closing member 70 is provided with a rectangular opening 74 at the center, and a roller 72 is attached along the upper and lower edges of the opening 74. The opening 74 corresponds to a throttle portion in the claims.

  A guide member 73 that guides the bag body 20 in the protective tube 60 toward the opening 74 is attached to the inner surface of the protective tube 60 of the closing member 70. The end of the closed side of the bag body 20 is positioned on the reamer 220 side, and the end of the opening side projects from the space between the guide members 73 of the opening 74 to the outside of the protection tube 60. Is held in. As will be described later, the opening 74 provided in the closing member 70 is formed when a grout is filled in a portion 20A protruding outward from the opening 74 of the closing member 70 of the bag body 20 (hereinafter referred to as a protruding portion). The width of the closing member 70 is adjusted so as not to reach the protective tube 60 side of the closing member 70.

  Returning to the description of the construction method again, next, as shown in FIG. 5, the diameter of the hole 120 is expanded by the reamer 220, and the protective tube 60 connected to the rear portion of the reamer 220 in the expanded diameter hole 120. Are drawn in a state in which the outer peripheral surface is in contact with the inner peripheral surface of the hole 120. Thereby, the inner peripheral surface of the hole 120 formed in the ground 100 is supported by the protective tube 60, and the stability of the ground 100 can be maintained even if the diameter of the hole 120 is increased. Before drawing the protective tube 60 into the hole 120, a lubricating liquid such as bentonite solution or cement / bentonite solution (hereinafter referred to as CB solution) is applied to the outer peripheral surface of the protective tube 60, or lubrication is performed from the reamer 220. It is preferable to leave the outer peripheral surface of the protective tube 60 covered with the lubricating liquid by discharging the liquid. Thereby, as will be described later, when the protective tube 60 is pushed out from the hole 120, the friction between the outer peripheral surface of the protective tube 60 and the inner peripheral surface of the hole 120 is reduced, and the protective tube 60 can be easily pushed out. it can.

  Next, as shown in FIG. 6, when the diameter expansion work of the hole 120 by the reamer 220 is completed and the end portion of the protective tube 60 reaches the ground surface opposite to the groove 110, the reamer 220 and the drill pipe 210 are connected. The grout injection pipe 230 is connected to the protruding portion 20 </ b> A of the bag body 20.

Next, as shown in FIG. 7, the grout 30 is set to a pressure (for example, 0.1 to 0.3 MPa) at which the water is not leached from the bag body 20 to the protruding portion 20 </ b> A by the grout injection pipe 230. Fill (hereinafter referred to as primary filling). At this time, as described above, since the width of the opening 74 is adjusted so that the grout 30 does not pass, when the grout 30 is filled in the projecting portion 20A of the bag body 20, as shown in FIG. The filling pressure acts as a force for pressing the closing member 70 in the axial direction of the hole 120. For this reason, as indicated by an arrow in the figure, the protective tube 60 is pushed out toward the end of the hole 120 on the opposite side of the groove 110. At this time, the bag body 20 filled with the grout 30 is immediately located at the portion where the protective tube 60 is pushed out, and the inner peripheral surface of the hole 120 is supported by the bag body 20, so that the ground 100 is unstable. Can be prevented.
Then, as shown in FIG. 8, the grout 30 is filled in the bag body 20 until the protective tube 60 and the closing member 70 are pushed out from the hole 120.

  Next, as shown in FIG. 9, the grout 30 is filled again with an injection pressure in the bag body 20 at a pressure (for example, about 0.5 MPa) that allows water to ooze out of the bag body 20 (hereinafter referred to as two). Called the next filling). Thereby, since the water | moisture content in the grout 30 oozes out from the bag body 20, the intensity | strength of the grout 30 improves.

  And the construction of the ground reinforcement structure 10 is completed when the grout 30 filled in the bag body 20 is cured. In the step of drawing the protective tube 20 into the hole 120, when the CB solution is applied to the outer peripheral surface of the protective tube 20 or when the CB solution is discharged from the reamer 220, the CB solution is removed from the bag 20 and the ground. Since it hardens | solidifies with 100, the adhesion strength of the bag body 20 and the ground 100 is improved.

  According to the present embodiment, the closing member 70 having the opening 74 is provided at the end of the protective tube 60, and the protruding portion 20A protruding from the opening 74 of the closing member 70 of the bag body 20 is filled with the grout 30. While the bag body 20 is filled with the grout 30, the protective tube 60 is pushed out from the hole 120 by the pressure to fill the grout 30. Thereby, since the part from which the protective tube 60 in the hole 120 is removed is immediately supported by the bag body 20 filled with the grout 30, the ground 100 can be prevented from becoming unstable.

  Further, when filling the grout 30 with a low injection pressure (for example, 0.1 to 0.3 MPa) as the bag body 20, water does not ooze out to the outside, and the injection pressure is set to a high pressure (for example, , 0.5 MPa), the water is oozed out to the outside, so that water is discharged during the secondary filling and the hardness of the grout 30 can be improved. In addition, in said embodiment, it replaces with performing a watertight process to the bag body 20, and when the admixture which prevents isolation | separation of a water | moisture content is mixed in a grout material, water will bleed out to the exterior in the case of primary filling. Alternatively, moisture may be discharged during the secondary filling.

  In addition, by applying a lubricating liquid to the outer peripheral surface of the protective tube 20 or discharging the lubricating liquid from the reamer 220, the protective tube 60 can be smoothly inserted into the hole 120. When the solution is applied, the CB solution remains on the inner peripheral surface of the hole 120 and improves adhesion to the bag body 20.

  In the above embodiment, the case where the opening 74 is formed at the end of the protective tube 60 and the closing member 70 including the roller 72 is attached above and below the opening 74 has been described. As shown in FIG. 12, a pair of arcuate members 171 at the top and bottom of the inner peripheral surface are attached to the end of the protective tube 60 so that an opening 174 is formed between these members 171. It is good also as forming the obstruction | occlusion part 170 with a small diameter compared with the other site | part of the pipe | tube 60. FIG.

  Further, as shown in FIG. 13, the outer side of the protective tube 60 from the intermediate part is formed in an arc shape on the inner peripheral surface of the end part of the protective tube 60, and the inner side of the protective tube 60 from the intermediate part By attaching a member 271 having a slope that gradually spreads toward the outer peripheral side toward the inner side of the outer ring so as to form a circular opening 274 in the center, the blocking portion 270 is It is good also as a structure to provide. In addition, although it is preferable to provide the inner side of the protective tube 60 from the middle portion as shown in FIG. 13, a slope that is recessed toward the outer periphery of the protective tube 60 is provided, but a flat slope may be provided.

  In the above embodiment, the hole 120 is expanded by the reamer 220 after the hole 120 is drilled by the drill bit 200. However, the hole having a diameter that allows the protective tube 60 to be inserted by the drill bit 200 is used. 120 may be drilled. In this case, the protective tube 60 and the bag body 20 are connected to the drill bit 200, and the drilling direction (from the left in the figure in the above example) while drilling the hole 120 with the drill bit 200. It is necessary to draw the protective tube 60 and the bag body 20 into the hole 120 in the right direction).

  In the above embodiment, the primary filling and the secondary filling are performed by the single injection pipe 230. However, the present invention is not limited to this. For example, as shown in FIG. At this time, a first injection pipe 230 is provided so as to open into the protruding portion 20A of the bag body 20, reaches the tip of the bag body 20, and opens at a plurality of locations in the bag body 20. 240 may be provided. In this case, as shown in FIG. 15, the primary filling is performed by the first injection pipe 230, and after the protective tube 60 is removed, the secondary filling is performed through the second injection pipe 240 as shown in FIG. . Since the second injection pipe 240 is opened at a plurality of locations in the bag body 20 as described above, by filling the grout through the second injection pipe 240, the bag body 20 is grouted at an equal pressure. Can be filled.

  Further, in the embodiment described with reference to FIGS. 14 to 16, the primary filling is performed by the first injection pipe 230, and after the protective tube 60 is removed, the secondary filling is performed by the second injection pipe 240. However, the present invention is not limited to this, and primary filling and secondary filling may be performed by the second injection pipe 240. That is, when the bag body 20 is disposed in the protective tube 60, the second injection pipe 240 is disposed so as to extend to the tip in the bag body 20. Then, the diameter of the hole 120 is expanded by the reamer 220, and the protective tube 60 is drawn into the hole 120, and then the grout 30 is filled into the bag body 20 by the second injection pipe 240. At this time, as shown in FIG. 17, since the second injection pipe 240 is closed by the closing member 7, the grout 30 supplied into the second injection pipe 240 is not attached to the closing member 70 of the bag body 20. The portion protruding from the opening 74 to the outside of the protective tube 60 is filled. Since the filling pressure of the grout 30 works as a force for pressing the protective tube 60 in the axial direction of the hole 120, the protective tube 60 can be pushed out from the hole 120.

  In the above embodiment, the protective tube 60 is pushed out from the hole 120 only by the filling pressure of the grout 30 at the time of primary filling. However, the present invention is not limited to this, and the filling pressure of the grout 30 at the time of primary filling is used. In addition, a portion protruding from the ground surface of the protective tube 60 may be pulled. In this case, if the force pulling the protective tube 60 is too strong, the protective tube 60 is pulled out in a state where the protruding portion 20A of the bag body 20 is not sufficiently filled with the grout 30, and the ground 100 can be supported. Therefore, it is necessary to pull the protective tube 60 while maintaining the state in which the protruding portion 20A of the bag body 20 is sufficiently filled with the grout 30.

  In the present embodiment, the end portion of the protective tube 60 in which the bag body 20 is attached is connected to the rear portion of the reamer 220 and drawn into the hole 120 in advance. After pulling 60 into the hole 120, the bag body 20 may be disposed.

  In the above embodiment, the hole 120 having one end formed on the ground surface and the other end opened in the groove 110 and the reinforcing structure 100 is built in the hole 120 is not limited thereto. A reinforcing structure may be constructed in a hole that opens to the ground surface or a hole that opens in the groove at both ends.

It is a vertical sectional view showing a reinforcing structure constructed by the ground reinforcing method of the present embodiment. It is a vertical direction sectional view (the 1) for explaining the construction method of the ground reinforcement structure of this embodiment. It is vertical direction sectional drawing (the 2) for demonstrating the construction method of the ground reinforcement structure of this embodiment. It is vertical direction sectional drawing (the 3) for demonstrating the construction method of the ground reinforcement structure of this embodiment. It is a vertical direction sectional view (the 4) for explaining the construction method of the ground reinforcement structure of this embodiment. It is vertical direction sectional drawing (the 5) for demonstrating the construction method of the ground reinforcement structure of this embodiment. It is vertical direction sectional drawing (the 6) for demonstrating the construction method of the ground reinforcement structure of this embodiment. It is vertical direction sectional drawing (the 7) for demonstrating the construction method of the ground reinforcement structure of this embodiment. It is vertical direction sectional drawing (the 8) for demonstrating the construction method of the ground reinforcement structure of this embodiment. It is an enlarged view of the edge part on the opposite side to the side connected to the reamer of a protective tube, (A) is a vertical sectional view of an axial direction, (B) is an AA arrow line view in (A). It is a figure which shows a mode that pressing force acts on a closure member by filling the protrusion part of a bag body with grout. It is a figure which shows the structure of the obstruction | occlusion part of another embodiment, (A) is a vertical sectional view of an axial direction, (B) is an AA arrow directional view in (A). It is a figure which shows the structure of the obstruction | occlusion part of another embodiment, (A) is a vertical sectional view of an axial direction, (B) is an AA arrow directional view in (A). It is a vertical sectional view (the 1) for explaining the method of filling grout using two injection pipes. It is a vertical sectional view for explaining a method of filling grout using two injection pipes (part 2). It is a vertical sectional view (the 3) for explaining the method of filling grout using two injection pipes. It is a vertical sectional view which shows a mode that the grout primary filling is performed with the 2nd injection pipe.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Reinforcement structure 20 Bag body 20A Protrusion part 30 Grout 50 Fill 51 Line 60 Protective pipes 70 and 170 Closure member (closure part)
72 Roller 73 Guide member 74 Opening 100 Ground 110 Groove 120 Hole 200 Drilling bit 210 Drill pipe 220 Reamer 230 (First) Grout injection pipe 240 (Second) Grout injection pipe

Claims (10)

A method of reinforcing the ground,
A protective tube disposing step of forming a hole in the ground and disposing a protective tube having a throttle part partially opened at one end in the hole so that an outer peripheral surface thereof is in contact with an inner peripheral surface of the hole When,
A cylindrical bag body having one end closed and the other end opened is passed through the throttle portion, the one end is located inside the protective tube, and the other end protrudes from the throttle portion to the outside of the protective tube. A bag arrangement step to arrange
A filling step of pressurizing and filling a curable filler from the opening into the bag body and pushing the protective tube to the other end side of the through hole by a pressure of filling the filler;
The ground reinforcement method characterized by providing. The bag body arranging step is performed before the protective tube arranging step,
In the protective tube arranging step,
The ground reinforcement method according to claim 1, wherein the protective tube in which the one end of the bag body is disposed is disposed in the hole. The protective tube arranging step includes:
Drilling step for forming a small-diameter hole in the ground;
A diameter expansion step of expanding the small diameter hole by a diameter expansion means and drawing a protective tube connected to the diameter expansion means into the diameter expanded hole;
The ground reinforcement method according to claim 1 or 2, characterized by comprising: In the protective tube arranging step,
The ground reinforcement method according to any one of claims 1 to 3, wherein the protective tube is disposed in the hole so that an outer peripheral surface thereof is covered with a lubricating liquid.   5. The ground reinforcement method according to claim 4, wherein the lubricating liquid is a cement / bentonite solution.   The ground reinforcement method according to any one of claims 1 to 5, wherein after the filling step, a refilling step of pressurizing and filling the filler into the bag is performed. The ground reinforcement method according to claim 6,
In the refilling step, the ground reinforcing method is characterized in that the filling material is filled using an injection pipe that reaches an end portion of the bag body and opens at a plurality of locations in the bag body.   In the filling step, the filler reaches the end of the bag body, and the filling material is filled using injection pipes that open at a plurality of locations in the bag body. The ground reinforcement method according to any one of claims   The ground reinforcement method according to any one of claims 1 to 8, wherein a roller is provided on an edge of the throttle portion.   A ground reinforcement structure constructed by the method according to any one of claims 1 to 9.

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