JP2006176999A - Natural ground reinforcing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method capable of surely reinforcing natural ground by accurately driving a long-sized steel pipe. <P>SOLUTION: Before driving the long-sized steel pipe 12, after driving a resin guide pipe 11 such as a vinyl chloride pipe having a diameter larger than a diameter of the steel pipe 12 in a cutting face surface of the natural ground 50, the steel pipe 12 is inserted into the guide pipe 11, and while drilling a hole in the natural ground 50 in front of a cutting face, the steel pipe 12 is driven in the natural ground 50. A push-cutting hole-drilling dummy pipe 16 is connected to a rear end part of the steel pipe 12, and the rear end part of the steel pipe 12 is driven up to coming to the vicinity of a tip part of the guide pipe 11. Before injecting a ground solidifying agent, an injection double packer 30 is inserted into the steel pipe 12, and the ground solidifying agent is injected. After blocking up clearance between the steel pipe 12 and the guide pipe 11 in advance by injecting the ground solidifying agent into the clearance between the steel pipe 12 and the guide pipe 11, the surrounding natural ground 50 is reinforced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to a method for reinforcing a natural ground in which a plurality of long steel pipes are placed in a natural ground in front of a face before tunnel excavation, and an injection material is injected from the steel pipe into the natural ground to reinforce the natural ground. It is.

In general, when a tunnel is dug into a soft ground, a ground receiving work for reinforcing a natural ground ahead of the face is performed prior to tunnel excavation. There is an injection type long tip receiving method as an example of the ground receiving method. As shown in FIG. 7A, this construction method uses an excavator 60 such as a drill jumbo generally used for tunnel excavation in a natural ground 50 in front of the face, and an elevation angle of about 5 degrees from the back of the support 51. A plurality of steel pipes 52 are connected while being driven, an injection pipe (not shown) is inserted into the steel pipe 52, a ground solidifying agent is injected into the natural ground 50, and the natural ground 50 is reinforced. 7 (b), the long steel pipe 53 is placed in a necessary reinforcing range (for example, an elevation angle θ is 120 degrees) along the top face of the face, and then the steel pipe 53 is placed. Fill the inside with a filler to reinforce.
When the long steel pipe 53 is driven, as shown in FIG. 8 (a), the drilling rod 13 provided with a diameter expanding bit 13a for drilling is inserted into the steel pipe 52 as shown in FIG. Then, the other end side of the drilling rod 13 is connected to a rock drill 61 mounted on the guide cell 62 of the excavator 60, and the steel pipe 52 is inserted into the ground 50 while drilling the ground 50. Insert into. At this time, as the steel pipe 52, a steel pipe 53 having a length of about 3 m is sequentially added and a long steel pipe 53 is driven. Moreover, in order to extend and construct the support work 51, since it is necessary to remove the lower part from the support work 51 of the said steel pipe 52, in order to make removal work easy, in FIG.8 (b). As shown, the pipe 54 at the rearmost end of the long steel pipe 53 is replaced with a steel pipe 52 and is a resin pipe that is easily crushed, such as a vinyl chloride pipe (see, for example, Patent Documents 1 and 2).
JP 2000-186490 A JP 2003-155888 A

However, in the conventional injection-type long tip receiving method, a plurality of steel pipes 52 are joined to form a long steel pipe 53, so that a desired placing angle cannot be obtained and the long steel pipe 53 is accurately driven. Not only is it difficult to install, but it takes time and labor to connect the steel pipes 52 and 52, so that the work efficiency is poor.
Therefore, when placing a long steel pipe, a guide pipe having a diameter larger than that of the long steel pipe is placed in advance in the ground, and is driven while guiding the propulsion of the long steel pipe. If a dummy pipe is connected to the rear end of the steel pipe and the long steel pipe is inserted until the rear end of the steel pipe reaches the vicinity of the tip of the guide pipe, the long steel pipe can be placed with high accuracy. However, because there is a gap between the long steel pipe and the guide pipe, there is a risk that earth and sand or water may enter through the gap or the ground solidification material injected into the ground will leak. Therefore, there is a problem that the natural ground cannot be sufficiently reinforced.

  The present invention has been made in view of conventional problems, and an object of the present invention is to provide a method capable of placing a long steel pipe with high accuracy and reliably reinforcing a natural ground.

In the invention according to claim 1 of the present application, a long steel pipe is inserted into a ground pipe in front of a face face, and the long steel pipe is placed in the ground while drilling the ground. Further, after connecting a dummy pipe to the rear end of the long steel pipe and inserting the steel pipe into the guide pipe until the rear end of the steel pipe comes to a predetermined position in the guide pipe In the method for reinforcing a natural ground in which a ground solidifying agent is injected from the inside of the steel pipe into a surrounding natural ground to reinforce the natural ground, before the injection of the ground solidifying agent, the long steel pipe and the dummy pipe A double packer for injection is inserted into the connecting portion, and the ground solidifying agent is injected into the connecting portion between the steel pipe and the dummy pipe.
According to a second aspect of the present invention, in the method for reinforcing a natural ground according to the first aspect, the guide tube is a resin tube.

According to the present invention, a long steel pipe is driven into a natural ground using a guide pipe, and further, a dummy pipe is connected to a rear end portion of the long steel pipe to connect the long steel pipe to a rear end portion of the steel pipe. When the steel pipe is inserted into the guide pipe until it reaches a predetermined position in the guide pipe, and then the ground solidification agent is injected into the surrounding ground from the inside of the steel pipe to reinforce the ground, the ground solidification Before injecting the agent, since the double packer for injection was inserted into the connection part between the long steel pipe and the dummy pipe, and the ground solidifying agent was injected into the connection part between the steel pipe and the dummy pipe, The long steel pipe can be placed with high accuracy and the gap between the long steel pipe and the guide pipe can be closed in advance, so that earth and sand can be removed from the gap between the long steel pipe and the guide pipe after collecting the dummy pipe. In addition to preventing water from entering, the ground solidified in the ground Since mode can also be eliminated, it is possible to reliably reinforce the ground.
Further, if the guide pipe is a resin pipe, it can be used as the rearmost end pipe to be removed at the time of support construction, so that the work efficiency can be further improved.

Hereinafter, the best mode of the present invention will be described.
1 (a) to 1 (e) are schematic diagrams showing an outline of a work procedure of a long-length tip receiving method according to the best mode of the present invention. In this example, first, as shown in FIG. 1 (a), FIG. Prior to the casting of the long steel pipe 12, a guide pipe 11 having a diameter larger than that of the long steel pipe 12 and having a length of about 3 m and the same length as that of a normally used steel pipe is formed in the ground 50 A long steel pipe 12 is driven by using the guide pipe 11 as a guide and driving it with an elevation angle of about 5 degrees from the back surface of the support work 51 at a position closest to the face. At this time, the entire guide tube 11 has already been driven so that the guide tube 11 is not exposed to the portion of the natural ground 50 that has not been reinforced by the long steel tube 12 already driven. It is preferable to drive into a location located on the lower side of the long steel pipe 12 (the support work 51 side).
In this example, a resin pipe such as a vinyl chloride pipe is used as the guide pipe 11. Then, as shown in FIG. 2 (a), the guide tube 11 is put on the outside of a steel pipe (hereinafter referred to as a normal steel pipe) 52 that is normally used, and the tip of the normal steel pipe 52 is expanded for drilling. A drill bit 13 provided with a diameter bit 13a and a base end 13b connected to the output shaft 21a of the rock drill 21 of the drilling device 20 through the coupling 14 is inserted. Is advanced along the guide cell 22 and the normal steel pipe 52 is propelled while drilling the ground 50 in front of the face. At this time, it is preferable to attach a shift stopper 15 with a seismic isolation device so that the hit of the rock drill 21 is not directly transmitted to the guide tube 11.
After the guide tube 11 has been placed, the slip stopper 15 is removed to collect the ordinary steel pipe 52, and the diameter of the expanded bit 13a is reduced to collect the drilling rod 13. Thereby, the resin-made guide pipe | tube 11 can be driven in the natural ground 50 ahead of a face. Note that after the guide tube 11 is placed, mouth caulking is performed with sprayed concrete to prevent the guide tube 11 from being pulled out.
Next, as shown in FIG. 1B, a long steel pipe 12 having a length of 9 m (the length is shortened in the figure) is inserted into the guide pipe 11. Specifically, as shown in FIGS. 2B and 2C, a gripping portion 23n that grips the long steel pipe 12 is mounted on a guide cell 22 on which a rock drill 21 of the drilling device 20 is mounted and slid. , 24n, and slide centerers 23, 24, which are attached to the guide cell 22 and include elevating means 23m, 24m that extend and contract the distance between the gripping portions 23n, 24n and the guide cell 22, along the guide cell 22. The holding member 25 is also installed on the upper surface of the rock drill 21 and the long steel pipe 12 is attached to the upper portion of the rock drill 21 by the slide centerers 23 and 24 and the holding member 25. Then, the rear slide centerr 24 is slid forward (face side), and the long steel pipe 12 is inserted into the guide pipe 11. At this time, a drilling rod 13 extended in advance is inserted into the inserted long steel pipe 12, and a coupling 14 for connecting to the rock drill 21 is connected to the rear end of the long steel pipe 12. Install it.
The length of the long steel pipe 12 is appropriately set according to the size of the tunnel, the stroke length of the drilling device 20 to be used, etc., and does not necessarily need to be 9 m.

After insertion of the long steel pipe 12, as shown in FIG. 1 (c), while drilling the natural ground 50 in front of the face with the diameter expansion bit of a drilling rod (not shown) in the long steel pipe 12, the above-mentioned The long steel pipe 12 is driven into the natural ground 50. Specifically, as shown in FIG. 3A, after the rock drill 21 is slid forward and moved to the vicinity of the coupling 14, the guide cell 22 is raised by the guide cell lifting means 26. At the same time, the lifting means 23m and 24m are operated to reduce the distance between the gripping portions 23n and 24n of the slide centerers 23 and 24 and the guide cell 22, and the center of the rock drill 21 and the center of the long steel pipe 12, that is, After the heights of the output shaft 21a of the rock drill 21 and the connecting portion of the coupling 14 are matched, the position of the rock drill 21 is adjusted, and the rock drill 21 and the coupling 14 are adjusted. And connect.
During the above operation, the speed at which the distance between the gripping portions 23n, 24n and the guide cell 22 is reduced is synchronized with the rising speed of the guide cell 22 so that no excessive force is applied to the long steel pipe 12. There is a need to. Thereby, the said long steel pipe 12 and the rock drill 21 can be reliably connected, with the insertion angle of the long steel pipe 12 maintained.
Thereafter, as shown in FIG. 3B, the long steel pipe 12 is driven into the natural ground 50 by sliding the rock drill 21 forward while operating the rock drill 21.
At this stage, most of the long steel pipe 12 is inserted into the ground 50 in front of the face, but about 3 m at the rear is in the guide pipe 11. Therefore, as shown in FIG. 1 (d), a dummy hole 16 for a cut hole is connected to the rear end portion of the long steel pipe 12, and the rear end portion of the long steel pipe 12 is connected to the guide pipe 11. The long steel pipe 12 is inserted into the guide pipe 11 and driven until it reaches a predetermined position. In this example, in order to effectively use the long steel pipe 12, the rear end portion of the long steel pipe 12 is inserted until it comes close to the front end portion of the guide pipe 11.

That is, as shown in FIG. 4 (a), after removing the coupling 14 and sliding the rock drill 21 backward, the drilling rod 13 is extended and the rear end of the long steel pipe 12 is extended. The dummy tube 16 is connected to the above. And after connecting the rear-end part of the said dummy pipe 16 and the output shaft 21a of the rock drill 21 by the said coupling 14, as shown in FIG.4 (b), driving the rock drill 21 forward. The long steel pipe 12 is further inserted into the ground 50 in front of the face. Thereby, the rear end part of the long steel pipe 12 can be inserted into the ground 50 until it comes close to the front end part of the guide pipe 11. The coupling 14 may be omitted, and the long steel pipe 12 may be inserted in a state where the rear end portion of the dummy pipe 16 and the output shaft 21a of the rock drill 21 are in contact with each other.
Next, as shown in FIG.1 (e), the double packer 30 for injection | pouring is inserted in the said long steel pipe 12, and a ground solidification agent is inject | poured. 5 (a) to 5 (c) are diagrams showing details of the injection method of this example. First, an injection double packer 30 is installed at the connection portion between the long steel pipe 12 and the dummy pipe 16, and the above connection is made. After injecting the ground solidifying agent into the part, the gap between the long steel pipe 12 and the guide pipe 11 is closed in advance, and the treatment to prevent the intrusion of earth and sand from the gap between the long steel pipe 12 and the guide pipe 11, The double packer 30 is moved into the long steel pipe 12 and solidified into a ground 50 around the long steel pipe 12 from the injection hole 12h with a check valve provided in advance on the side surface of the long steel pipe 12. An earth agent 50 is injected to reinforce the natural ground 50. FIG. 6 is a diagram showing an example of the configuration of the above-described double packer 30 for injection. The injection device main body 31 is connected to an injection liquid transfer pipe (not shown), and is provided before and after the injection hole of the injection device main body. The two long packers 32 (32a, 32b) and the caster 33 for insertion which is a traveling means are provided. Air is introduced into the packers 32a, 32b from an air pipe (not shown) to expand the long packer 32a, 32b. After partitioning the inner space of the connecting portion between the steel pipe 12 and the dummy pipe 16, the ground solidifying agent sent from the injection liquid transfer pipe is passed through the injection hole to the long steel pipe 12 and the guide pipe 11. It injects into the natural ground 50 through the gap. Since the ground solidifying agent penetrates and solidifies into the natural ground 50, the gap between the long steel pipe 12 and the guide pipe 11 is closed in advance, and the infiltration of earth and sand and water from the gap between the long steel pipe 12 and the guide pipe 11 is performed. This can prevent the leakage of ground solidifying material injected into the ground. Therefore, compared to the case where the ground solidifying agent is simply injected from the long steel pipe 12, the natural ground 50 can be reliably reinforced.
Thereafter, the double packer 30 and the dummy pipe 16 are collected, and a filler is injected into the long steel pipe 12 using a vinyl chloride pipe 17 for filling the steel pipe. Finally, the guide tube 11 placed at a position corresponding to the lower part is removed from a support not shown in the figure by cutting or the like to construct the next support. Since the guide tube 11 is a resin tube such as a vinyl chloride tube, the removal operation can be easily performed.

Thus, according to this best mode, prior to the casting of the long steel pipe 12, the resin guide pipe 11 such as a vinyl chloride pipe having a diameter larger than the diameter of the long steel pipe 12 is grounded. After driving into the face of the mountain 50, the long steel pipe 12 is inserted into the guide pipe 11, and the long steel pipe 12 is driven into the ground 50 while drilling the ground 50 in front of the face. Further, a dummy tube 16 for a cut hole is connected to the rear end portion of the long steel pipe 12 and the rear end portion of the long steel pipe 12 is driven until it comes close to the front end portion of the guide tube 11. Therefore, the long steel pipe 12 can be driven with high accuracy. Further, before the ground solidifying agent is injected, the double packer 30 for injection is inserted into the long steel pipe 12 to inject the ground solidifying agent, and the ground solidifying agent is inserted into the gap between the long steel pipe 12 and the guide tube 11. Since the surrounding natural ground 50 is reinforced by previously injecting the gap between the long steel pipe 12 and the guide pipe 11, earth and sand and water are removed from the gap between the upper long steel pipe 12 and the guide pipe 11. Can be prevented, and the solidification material injected into the ground can be prevented from leaking. Therefore, compared to the case where the ground solidifying agent is simply injected from the long steel pipe 12, the natural ground 50 can be reliably reinforced.
Further, in this example, the guide tube 11 is made of a resin tube, and this can be used as it is as the tube at the rearmost end to be removed when the support work 51 is constructed. Propulsion work can be omitted and work efficiency can be improved.

  As described above, according to the present invention, a long steel pipe can be driven with high accuracy without using a large excavator, and a natural ground can be reinforced efficiently and reliably. .

It is a schematic diagram which shows the outline | summary of the work procedure of the elongate tip receiving method which concerns on the best form of this invention. It is a figure which shows the casting method of the long steel pipe which concerns on this best form. It is a figure which shows the casting method of the long steel pipe which concerns on this best form. It is a figure which shows the casting method of the long steel pipe which concerns on this best form. It is a figure which shows the injection | pouring method of the chemical | medical agent which concerns on this best form. It is a figure which shows one structural example of a double packer. It is a figure which shows the outline | summary of the conventional long tip receiving method. It is a figure which shows the conventional casting method of a long steel pipe.

Explanation of symbols

11 guide pipe, 12 long steel pipe, 12h injection hole with check valve, 13 drilling rod,
13a Expanding bit, 13b Base end of drilling rod, 14 Coupling,
15 Displacement stopper, 16 Dummy pipe for punching hole,
20 drilling device, 21 rock drill, 21a output shaft, 22 guide cell,
23, 24 Slide Centrizer, 23m, 24m Lifting means,
23n, 24n Slide centerer gripping part, 25 holding member,
30 double packers, 50 grounds, 51 supporters, 52 ordinary steel pipes.

Claims (2)

  A long steel pipe is inserted into a guide pipe placed in front of the face and a long steel pipe is placed in the ground while drilling the ground, and the rear end of the long steel pipe After connecting the dummy pipe to the long steel pipe and inserting the steel pipe into the guide pipe until the rear end of the steel pipe is at a predetermined position in the guide pipe, from the inside of the steel pipe to the surrounding natural ground In the method of reinforcing a natural ground in which a ground solidifying agent is injected to reinforce the natural ground, before injection of the ground solidifying agent, a double packer for injection is inserted into a connecting portion between the long steel pipe and the dummy pipe. A method for reinforcing a natural ground characterized in that a ground solidifying agent is injected into a connecting portion between the steel pipe and the dummy pipe.   The method for reinforcing a natural ground according to claim 1, wherein the guide tube is a resin tube.

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