JP2010112128A - Reinforcement method of ground, reinforced ground - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reinforcement method of ground which enables surrounding soil improvement, while performing vertical seam construction without protracting a construction period. <P>SOLUTION: In several places on the surface of the ground, a rotary percussion having a mechanism for discharging grout from its drill tip is used to drill a hole 30 on the ground surface, a core material 31 is inserted into the hole 30, the grout 32 is pressed into the hole 30 up to near intermediate height from the drill tip with top of the hole 30 sealed by rubber packing, the drill is removed from the hole 30, a packer 10 for infusing grout equipped with both a filling pipe 11 and a bag 12 prepared so as to surround this filling pipe 11 is inserted into the hole 30, then the grout 32 is pressed into the hole 30 through the filling pipe 11 with the bag 12 inflated and closely attached to inner circumference surface of the hole. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention cuts a hole in the surface of a ground that may cause a face collapse such as a mountain tunnel wellhead or sinks the target ground, inserts a core material into the hole, and then injects grout into the hole, It is related with the method of reinforcing.

Conventionally, reinforcement by a vertical sewing method has been performed on slopes where face collapse such as mountain tunnel wellheads and subsidence of the target ground are likely to occur (see Non-Patent Document 1). The vertical sewing method is a method in which a hole is first drilled from a slope surface to a necessary depth, a core material is inserted into the drilled hole, and a grout material is filled in the hole. By embedding a plurality of core materials in a lattice pattern in the ground in this way, the core material shears against the sliding load, so that it is possible to suppress the occurrence of face collapse and the subsidence of the target ground.
NETIS, New Technology Information Providing System “Micropile Nailing Method”, [online], June 1, 2007, Ministry of Land, Infrastructure, Transport and Tourism, [Search September 26, 2008], Internet <URL: http: // www. netis.mlit.go.jp/RenewNetis/Search/Nt/NtDetail1.asp?REG_NO=CB-050045&TabType=2&nt=nt>

  Here, when strength was required for the ground of the slope, the ground was improved separately in addition to the vertical sewing method. However, when the ground improvement is separately performed in addition to the vertical sewing method, there is a problem that the construction period becomes longer.

  The present invention has been made in view of the above problems, and an object of the present invention is to make it possible to improve the surrounding ground while performing a vertical sewing method without prolonging the construction period.

  A ground reinforcing method according to the present invention includes a drilling step of drilling a hole in the ground surface by a drilling machine having a mechanism for discharging grout from a drill tip at a plurality of locations on the surface of the ground; A core material insertion step for inserting a core material, a first injection step for injecting grout from the tip of the drill into the hole to a substantially intermediate height in a state where the upper portion of the hole is sealed, and for injecting a grout In a state where an injection jig provided with an injection tube and a bag body provided so as to surround the injection tube is inserted into the hole, the bag body is inflated and brought into close contact with the inner peripheral surface of the hole, And a second injection step of injecting grout into the hole through the injection tube.

In the reinforcing method described above, in any one of the plurality of locations, the drilling step is performed in any one of the plurality of locations in parallel with performing the second injection step. At least one of the core material insertion step and the first injection step may be performed.
In the first injection step, an upper portion of the hole may be sealed by interposing a packing between the drill and the hole.

Further, when performing the first injection step or the second injection step at any of the plurality of locations, the portion of the plurality of locations where the second injection step has been completed. The hole may be sealed with a closing member.
The reinforced ground of the present invention is reinforced by the ground reinforcing method described above.

  According to the present invention, in the first and second injection steps, the top of the hole is sealed, so that grout can be pressed into the hole. For this reason, the grout permeates the surrounding ground, and the ground of the surrounding ground can be improved. In addition, after the completion of the first injection step, this drilling machine can be used for the drilling step in the other holes and the first injection step in parallel with the second injection step. The period can be shortened.

Hereinafter, an embodiment of a ground reinforcing method of the present invention will be described in detail with reference to the drawings.
The object of reinforcement of the present embodiment is earth and sand ground in the case of tunnel excavation of a sediment deposit such as a tunnel wellhead. The reinforcing method of this embodiment is to drill holes in a plurality of places at predetermined intervals in the vertical and horizontal directions on the surface of the ground, insert a core material into the holes, and inject grout into the holes. By this, the ground is shear reinforced.

  FIG. 1 is a view showing a grout injection packer 10 used in the reinforcing method of the present embodiment. As shown in FIG. 1, the grout injection packer 10 includes a long steel injection pipe 11 and upper and lower bag bodies 12 attached to an intermediate portion of the injection pipe 11 with a space therebetween.

  A cam lock 15 is attached to the upper portion of the injection pipe 11, and a grout press-fitting hose extending from the grout press-fitting device is connected to the cam lock 15, so that the grout pumped from the grout press-fitting device is passed through the injection pipe 11. , Can be discharged from its lower end.

  The bag 12 is composed of a tube having a two-layer structure of an outer cloth material and an inner rubber material, and the upper and lower edges thereof are attached to the outer peripheral surface of the injection tube 11 by a rubber band 13, and are attached to the tube. A sealed space is formed between the outer peripheral surface of the injection tube 11.

  Further, the grout injection packer 10 includes a pair of small-diameter air pipes 14 that pass through the inside of the injection pipe 11 and are attached so that the lower ends thereof open into the upper and lower bag bodies 12 respectively. A ball valve 16 is provided at the upper part of the pair of air pipes 14. With this configuration, the bag body 12 can be inflated by sending air or water from the upper end of the air pipe 14, and the bag body 12 is closed by the ball valve 16 being closed in this state. The expanded state can be maintained.

  FIG. 2 shows a leak prevention packer 20 used in the reinforcing method of the present embodiment. As shown in the figure, the leak prevention packer 20 is shorter than the grout injection packer 10, and is made of a steel injection pipe 21, a bag body 22 attached to an intermediate portion of the injection pipe 21, and an injection pipe 21. The air pipe 24 is attached so that the lower end thereof opens into the bag body 22 and the ball valve 26 is interposed at the top. As with the grout injection packer 10, the bag 22 can be inflated by sending air or water from the air pipe 24, and further, the bag 24 is closed by the ball valve 26 in this state. The state where the body 22 is expanded can be maintained. The leak prevention packer 20 is different from the grout injection packer 10 in that the upper end of the injection tube 21 is closed.

Hereinafter, the reinforcing method of the present embodiment will be described with reference to FIGS. 3A to 3G.
First, as shown in FIG. 3A, the ground is excavated by the rotary percussion 40 to form the holes 30. The rotary percussion 40 is a heavy machine including a drill 41 for excavating the ground, and a mechanism for injecting grout into a hole drilled from the tip of the drill 41. When excavating the ground, an annular rubber packing 50 is attached around the upper end of the drill 41 in a state where the drill 41 is inserted through the center hole.

Next, as shown in FIG. 3B, the core material 31 is inserted into the hole 30 formed in the ground.
Next, as shown in FIG. 3C, the rubber packing 50 is pressed downward by the rotary percussion 40 so that the rubber packing 50 is brought into close contact with the upper portion of the drill 41 and is brought into close contact with the ground surface at the periphery of the opening of the hole 30. The grout 32 is press-fitted into the hole 30 from the lower part of the drill 41 while the upper part of the hole 30 is sealed by the rubber packing 40 and the drill 41. At this time, since the upper end of the hole 30 is sealed by attaching the rubber packing 50 to the upper part of the drill 41 as described above, the grout 32 press-fitted into the hole 30 is effectively put into the surrounding ground. It can be infiltrated.

  Next, when the injection of the grout 32 is completed to substantially the intermediate height of the hole 30, the drill 41 of the rotary percussion 40 is removed from the hole 30 as shown in FIG. 3D. Next, as shown in FIG. 3E, the grout injection packer 10 with the bag 12 contracted is inserted into the hole 30 so that the upper portion of the core material 31 is accommodated in the injection tube 11. Then, air or water is pressed into the bag body 12 through the air pipe 14. Thereby, each bag body 12 expand | swells, it adheres to the internal peripheral surface of the hole 30, and the upper part of the hole 30 can be sealed. In addition, in this embodiment, since the several bag body 12 is attached to the packer 10 for grout injection | pouring, the upper part of the hole 30 can be sealed more reliably.

  Next, as shown in FIG. 3F, a grout pressure-feeding hose 70 extending from the grout press-fitting device is connected to the cam lock 15, and the grout 32 is pressed into the hole 30 through the injection pipe 11. At this time, the grout 32 can be effectively infiltrated into the surrounding ground by press-fitting the grout 32 into the hole 30 in a state where the upper portion of the hole 30 is sealed by the bag body 12.

  When the grout 32 is press-fitted into the hole 30 and there is a hole 30 in which the injection of the grout 32 has been completed in the vicinity thereof, before the grout 32 is press-fitted in advance, as shown in FIG. The leak prevention packer 20 is inserted into the hole 30 and air or water is pressed into the bag body 22 through the air pipe 24. As a result, the bag body 22 expands and comes into close contact with the inner peripheral surface of the hole 30, so that the upper portion of the hole 30 where the injection of the grout 32 has been completed is sealed by the leak prevention packer 20.

  In this way, by closing the top of the hole 30 where the injection of the grout 32 has been completed, the grout 32 is affected by the pressure propagated to the surrounding ground when the grout 32 is press-fitted into another hole 30 in the vicinity. Overflow from the hole 30 can be prevented.

Further, in parallel with the step of injecting the grout 32 using the grout injection packer 10 described with reference to FIG. 3F, the rotary percussion 40 is moved to the position where the next drilling is performed, and FIG. As described with reference to 3C, the hole 30 is drilled in the ground, the reinforcing bar 31 is inserted into the hole 30, and the grout 32 is injected to the intermediate height of the hole 30.
As described above, the steps described with reference to FIGS. 3A to 3F are performed at a plurality of locations on the ground surface, and the grout 32 press-fitted into the holes 30 is cured at each location, thereby completing the reinforcement of the ground.

  As described above, according to the present embodiment, the rubber packing 50 is attached to the upper portion of the drill 41 of the rotary percussion 40, and the bag body 12 of the grout injection packer 10 is inflated, so that the holes 30 are formed. The grout 32 can be press-fitted with the upper portion sealed, and the press-fitted grout 32 can be effectively infiltrated into the ground around the hole 30. Thereby, while being able to give the reinforcement with respect to the sliding load which acts on the ground by the vertical sewing method, the ground can be further reinforced by the penetration of the grout 32 into the ground.

  In addition, the grout 32 is injected into the lower part of the hole 30 by the rotary percussion 40, and the remaining grout 32 is press-fitted into the hole 30 by the grout injection packer 10, so that the grout 32 is press-fitted into the upper part of the hole 30. In parallel with this work, another hole 30 is drilled by the rotary percussion 40, the core material 31 is inserted into the hole 30, and the grout 32 is injected into the lower portion of the hole 30. it can. For this reason, work efficiency can be improved and construction can be performed in a short period of time.

  Further, when the grout 32 is press-fitted into the hole 30, the grout 32 is sealed in the hole 30 by closing the upper part of the other hole where the injection of the grout 32 in the vicinity thereof is completed with the leak-proof packer 20. Even if the pressure at the time of press-fitting propagates through the ground and acts on the grout 32 in the other hole 30, the grout 32 can be prevented from overflowing.

  In the present embodiment, the pair of bag bodies 12 are provided in the grout injection packer 10, but the present invention is not limited to this, and one or three or more bag bodies may be provided. Similarly, although only one bag body 22 is provided in the leak prevention packer 20, a plurality of bag bodies may be provided.

  Further, in this embodiment, the rotary percussion 40 is used for excavation of the hole and press-fitting of the grout into the hole. Any device that can be used can be used.

It is a figure which shows the packer for grout injection | pouring used for the reinforcement method of this embodiment. It is a packer for leak prevention used for the reinforcement method of this embodiment. It is a figure (the 1) for demonstrating the reinforcement method of the ground of this embodiment. It is a figure (the 2) for demonstrating the reinforcement method of the ground of this embodiment. It is a figure (the 3) for demonstrating the reinforcement method of the ground of this embodiment. It is FIG. (4) for demonstrating the ground reinforcement method of this embodiment. It is FIG. (5) for demonstrating the reinforcement method of the ground of this embodiment. It is FIG. (6) for demonstrating the ground reinforcement method of this embodiment. It is a figure (the 7) for demonstrating the reinforcement method of the ground of this embodiment.

Explanation of symbols

10 Grout injection packer 11, 21 Injection pipe 12, 22 Bag body 13, 23 Rubber band 14, 24 Air pipe 15 Cam lock 16, 26 Ball valve 20 Leakage prevention packer 30 Hole 31 Core material 32 Grout 40 Rotary percussion 41 Drill 50 Rubber packing

Claims (5)

A method of reinforcing the ground,
In several places on the surface of the ground,
Drilling step of drilling a hole in the surface of the ground by a drilling machine having a mechanism for discharging grout from the drill tip;
A core material insertion step of inserting a core material into the hole;
A first injection step of injecting grout from the drill tip into the hole to a substantially intermediate height with the top of the hole sealed;
An injection jig comprising an injection tube for injecting a grout and a bag body provided so as to surround the injection tube is inserted into the hole, and the bag body is expanded to the inner peripheral surface of the hole. And a second injection step of injecting grout into the hole through the injection tube in a close contact state. A ground reinforcing method according to claim 1,
In parallel with performing the second injection step at any of the plurality of locations,
A ground reinforcement method comprising performing at least one of the drilling step, the core material insertion step, and the first injection step at any one of the plurality of locations. A ground reinforcing method according to claim 1 or 2,
In the first injection step,
A ground reinforcement method, wherein an upper portion of the hole is sealed by interposing a packing between the drill and the hole. The ground reinforcing method according to any one of claims 1 to 3,
When performing the first injection step or the second injection step at any one of the plurality of locations,
The method for reinforcing a ground according to claim 1, wherein the hole in the plurality of places where the second injection step is completed is sealed with a closing member.   A reinforced ground reinforced by the ground reinforcing method according to any one of claims 1 to 4.