JP4732829B2 - Ground excavation method - Google Patents

Description

  The present invention relates to a construction method for excavating ground improved and improved by chemical solution injection.

In the ground excavation work, the ground is strengthened by injecting a chemical solution, which is an improving agent, into the ground and allowing it to harden for the purpose of reinforcing and stabilizing the soft ground or strengthening the foundation of the structure. Yes.
As this ground improvement construction method, an outer tube having a chemical solution outlet is embedded in the peripheral surface in a hole for chemical solution injection formed in the ground to be improved, and an inner tube or a packer with a chemical solution is supplied inside this outer tube. A sleeve injection method is widely implemented in which an inner tube is inserted or a chemical solution is poured into the outer tube to cause the chemical solution to flow out to the surrounding ground through the outer tube. Moreover, in order to reduce the environmental load in the soil, a construction method using a biodegradable resin as the outer tube is also known (see, for example, Patent Documents 1 and 2).

JP 2000-160547 A Japanese Patent Laid-Open No. 2001-323452

When injecting chemicals into the ground using an outer pipe, if a hard pipe made of vinyl chloride resin or ABS resin is used as the outer pipe, the outer pipe left behind in the soil will contaminate the ground. In addition, there is a problem that when the portion where the outer pipe is buried is excavated, it is necessary to separate and discard the outer pipe fragments mixed in the remaining soil.
In the conventional method using the outer tube made of biodegradable resin, the outer tube is buried in the ground by burying the outer tube, so that the outer tube does not remain after the decomposition. However, the excavation of the portion where the outer pipe is buried is performed after the outer pipe is disassembled, and there is a problem that the excavation work period is significantly prolonged. Therefore, for example, when the ground is strengthened by injecting chemicals to excavate a tunnel, biodegradable resin-made pipes are not used as the outer pipes for injecting chemicals, but exclusively vinyl chloride resin or ABS resin. The outer tube which consists of etc. was used. The actual situation was that these outer pipes were placed, the ground including the outer pipes was excavated after ground strengthening, and the outer pipes mixed with the remaining soil were separated and discarded.

  In view of such problems of the prior art, the present invention can perform excavation work at a location where the soil quality has been improved by injecting chemicals into the ground in a short period of time without separating and disposing of the remaining soil. The challenge is to make it.

Ground excavation method of the present invention for solving the above problems includes the steps of embedding the appropriate length ground by pouring while replenishing the outer tube made of a biodegradable resin in drilling a section of the ground to be excavated, the embedded has been a chemical solution to improve the ground into the outer tube to flow into or directly through the inner tube inserted into the tube, it was flowing out from the holes formed in the outer tube circumference is injected into the ground soil a step of reinforcing, the outer tube before the outer pipe is decomposed in the soil and a step of excavating the ground in a place where it has been pouring, of the outer tube mixed in the with the drilling crushed by drilling muck And a step of decomposing fragments in the residual soil discharged by excavation.
Furthermore, an outer pipe made of a biodegradable resin is placed in the ground of an appropriate length by placing an outer pipe made of non-biodegradable resin on the ground around the face while being added , and at least an outer pipe made of biodegradable resin in the excavation cross section of the face a step of embedding a suitably length ground by pouring while replenishing a chemical solution to improve the soil is allowed to flow in or directly through the inner tube inserted into the pipe to said buried respectively in the outer tube, A process of reinforcing the ground by flowing it out of a hole formed in the outer peripheral surface of the outer pipe and reinforcing the ground, and placing the outer pipe before the outer pipe made of the biodegradable resin is decomposed in the soil A step of excavating the ground at the location, and a step of decomposing debris of the outer pipe that has been crushed along with the excavation and mixed into the excavation sludge in the remaining soil discharged by excavation.

  The present invention is a method of excavating the ground by alternately performing ground reinforcement and excavation by injecting a chemical solution. For example, in tunnel excavation, an outer tube made of biodegradable resin and an outer tube made of other materials are placed on the face so that at least the outer tube made of biodegradable resin is embedded in the face excavation section. Then, the surrounding ground is strengthened by injecting the chemical into the ground through these outer tubes. The outer tube made of biodegradable resin once placed in the soil is discharged in a state of being mixed in the cutting sludge as the excavation progresses.

  As the biodegradable resin used for forming the outer tube, a plant-derived resin such as polylactic acid (PLA) is suitable. Further, for example, aliphatic polyester-based biodegradable resins containing poly-3-hydroxybutyric acid (PHB) as a constituent, polyols such as 1,4-butanediol, and aliphatic dicarboxylic acids such as succinic acid and adipic acid Biodegradable resins obtained by condensation polymerization using as a main raw material may be used, and other raw materials such as polyesters, polyamides, polysaccharides, PVAs, and natural polymers such as starch may be used. A degradable resin may be appropriately selected and used.

  The outer pipe can be placed by transmitting the power of the rock drill to a drilling bit attached to the tip of the outer pipe or a diameter expanding bit attached to the tip of the inner rod inside the outer pipe. Moreover, you may make it press-fit the outer pipe | tube which obstruct | occluded the front end to the ground. Further, a drilling hole having a predetermined depth may be formed in the ground by boring, and the outer tube may be inserted into the drilling hole, and the outer tube can be embedded by an appropriate method or means.

  In addition, the chemical solution can be injected by passing an inner tube (insert tube) through the outer tube having the chemical solution jet outlet, supplying the chemical solution to the inner tube and flowing it out through the outer tube, or with a packer in the outer tube. It can be performed by an appropriate method or means for injecting the chemical solution into the ground through the outer tube, such as a method of inserting the inner tube and causing the packer to flow the chemical solution to the ground at a desired depth and position. The chemical solution may be directly flowed into the outer tube, and the chemical solution may be discharged from the hole formed on the outer peripheral surface of the outer tube.

  The chemical solution to be injected is a chemical solution that strengthens the ground, and depending on the geology, urethane-based injection materials such as silica resin, or cement-based injection materials such as cement bentonite, cement milk, cement-based rapid-hardening admixture, and special fast-setting cement Etc. can be used selectively.

  After the ground strengthening is completed by chemical injection, the face is excavated. At that time, at least a biodegradable resin outer pipe placed in the excavation section is crushed along with excavation and discharged together with the remaining soil. In this remaining soil, the broken pieces of the crushed biodegradable resin outer tube are decomposed.

  According to the present invention, an outer tube made of non-biodegradable resin is placed around the face, and an outer tube made of biodegradable resin is placed in the excavation cross section, and the chemical solution is injected through each outer tube. After strengthening the ground, excavation of the excavation surface without waiting for disassembly of the biodegradable resin outer pipe in the soil makes it possible to excavate the tunnel in a short period of time. The fragments of the outer tube made of biodegradable resin discharged together with the remaining soil are biodegraded by microorganisms in the soil in a state where they are mixed and buried in the remaining soil, so that the fragments do not remain in the soil. Therefore, there is no contamination in the soil by the outer pipe, and it is not necessary to separate and discard the outer pipe and the soil. When disposing of the remaining soil, there is no need for separation treatment, so that it is possible to reduce the processing cost of industrial waste, and it is possible to reduce the construction cost cost in combination with the shortening of the construction period.

A preferred embodiment of the present invention will be described with reference to the drawings.
1 and 2 are diagrams showing a front cross section and a side cross section of a face in a tunnel when the present invention is applied to excavation of a tunnel, and FIG. 3 shows a process of injecting a chemical solution by placing an outer pipe on the ground. FIG. 4 is a side sectional view of a tunnel for explaining the process of placing an outer pipe on the upper surface of the face, and FIG. 5 is a cutaway view of an example of the outer pipe used in the process of FIG. FIG.

  The present invention is a method of excavating the ground by alternately strengthening and excavating the ground by injecting chemical liquid, and after injecting the chemical liquid into the ground through the outer tube placed on the ground at the face, the geology is reinforced and improved The face is excavated and the outer pipe is biodegraded in the remaining soil discharged by excavation.

  As shown in FIGS. 1 and 2, the outer pipe 2 driven in the face 1 of the mine shaft has an outer pipe 2 </ b> A other than a biodegradable resin on the lower surface and side surface of the mine road that is a peripheral portion of the face 1. A plurality of places are placed at predetermined intervals, and only the outer tube 2B made of a biodegradable resin is placed at predetermined positions on the face of the cutting face 1 (front side in the excavation direction). On the oblique upper surface of the face 1 in the direction of digging, a plurality of outer pipes connecting the outer pipe 2A made of non-biodegradable resin and the outer pipe 2B made of biodegradable resin are placed along the face top (see FIG. 1). 4). The placement length, placement location, and placement interval of the outer tube 2 placed on each part of the face 1 can be appropriately set according to the geology and the like.

Placing the outer tube 2 can be performed in the process shown in FIG. 3, for example, by using a driving device 3 as shown in FIG.
In FIG. 3, first, a rock drill bit 3a is attached to the distal end portion of the outer pipe 2 through the inside of the outer pipe 2, and the ground is struck by the rock drill bit 3a by the driving device 3 or is drilled while rotating. A hole is drilled (FIG. (A)), and the outer tube 2 is sequentially cast while being added as appropriate, and the outer tube 2 is buried in the ground for an appropriate length (FIG. (B)).
In addition, on the oblique upper surface of the face 1 in the digging direction, as shown in FIG. 4, the outer pipe 2A made of a material other than biodegradable resin is placed at the head, and the outer pipe 2A made of the same material is sequentially cast along the face roof. When the outer pipe 2A is driven for a predetermined length, the outer pipe 2B made of biodegradable resin is connected to the end of the outer pipe 2A with a screw joint or the like, and the outer pipe 2A is driven most. The outer pipe 2B is embedded within the range of the excavation cross section on the near side, and the outer pipe 2A is embedded in a portion beyond the excavation range ahead.

  Similarly, the other outer pipe 2 placed around the face 1 also has an outer pipe 2A made of a material other than a biodegradable resin at a portion exceeding the excavation section of the face 1 at least in the excavation section. The outer tube 2B made of biodegradable resin is used. As shown in FIG. 5, for example, each outer tube 2 of each material is provided with a plurality of apertures 21 that are chemical liquid outlets on the outer periphery thereof at an appropriate interval along the length direction. .

  After placing the outer tube 2 into the ground for a predetermined length, the inner tube 4 having the injection tube 4a is inserted into the outer tube 2 (FIG. 3C), and the ground is passed through the inner tube 4 and the outer tube 2. Inject chemicals. The chemical solution to be used is appropriately selected according to the geology of the ground to be improved.

  After strengthening the ground, move to the excavation process of face 1. At that time, at least the outer tube 2B made of biodegradable resin placed in the excavation section of the face 1 is crushed along with excavation, and the fragments are discharged together with the remaining soil.

Then, the outer pipe 2A that has been buried without being excavated is left in the buried position, while the fragments of the outer pipe 2B that have been discharged mixed with the remaining soil are mixed in the remaining soil, and after an appropriate period of time, Biodegraded by microorganisms in the soil.
In this case, the remaining soil mixed with the fragments of the outer pipe 2B is surely disassembled by leaving the fragments in the remaining soil and leaving it in contact with the remaining soil. Can do. The remaining soil including the fragments of the outer tube 2B discharged from the face, and the remaining soil after the outer tube 2B is biodegraded in the soil can be treated in the same manner as ordinary soil. The soil discharged by excavation does not require special disposal such as separation.

  In the illustrated embodiment, the process of excavating a tunnel horizontally in the ground is shown. However, the present invention is also applicable to the case of drilling vertically with respect to the ground or the case of drilling obliquely with respect to the ground. Is possible. The position and direction of excavation do not matter. In addition, the outer tube may be formed by drilling a hole having a predetermined depth in the ground in advance, and may be embedded by being pushed into the hole. Furthermore, the excavation bit used in the outer tube driving may be collected using a diameter expansion bit or the like. The injection of the chemical solution can be performed by an appropriate method or means other than the illustrated form.

It is a front cross-sectional view of a face when the construction method of the present invention is applied to excavation of a tunnel. It is a sectional side view of a face when the construction method of the present invention is applied to excavation of a tunnel. It is the figure which showed the process of placing an outer pipe | tube in the ground and inject | pouring a chemical | medical solution. It is a sectional side view of a mine shaft for explaining the process of placing an outer pipe on the upper surface of the face. It is the figure which fractured | ruptured and showed the half surface of an example outer tube used at the process of FIG.

Explanation of symbols

1 face, 2, 2A, 2B outer pipe, 21 opening, 3 casting device, 3a rock drill bit, 4 inner pipe, 4a injection pipe

Claims (2)

A process of placing an outer pipe made of biodegradable resin in the excavation cross section of the ground to be excavated while burying it in an appropriate length of ground, and
The buried a chemical solution to improve the ground into the outer tube to flow into or directly through the inner tube inserted into the tube, which was allowed to escape hole formed in the outer tube circumference by injecting into the ground A process of reinforcing the ground,
Excavating the ground where the outer pipe is placed before the outer pipe is decomposed in the soil;
A ground excavation method including a step of decomposing fragments of the outer pipe that are crushed during the excavation and mixed in excavation sludge in the residual soil discharged by excavation. A process of placing an outer pipe other than a biodegradable resin on the ground around the face while burying it in an appropriate length of ground ,
A step of laying out an outer tube made of biodegradable resin at least in the excavation cross section of the face and burying in an appropriate length of ground ,
A chemical solution to improve the ground into the buried respectively in the outer tube is introduced through the inner tube inserted or directly to the tube, which was injected into the ground to flow out from the outer tube circumference hole formed The process of reinforcing the ground,
Excavating the ground where the outer pipe is placed before the outer pipe made of the biodegradable resin is decomposed in the soil;
A ground excavation method including a step of decomposing fragments of the outer pipe that are crushed during the excavation and mixed in excavation sludge in the residual soil discharged by excavation.

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