JP3050437B2 - Underground cavity inner wall holding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for retaining an inner wall of an underground cavity formed after removing an underground pipe.

[0002]

2. Description of the Related Art Conventionally, there has been no method for holding the inner wall of an underground cavity as described above. For this reason, in the work of filling the underground cavity with soil and the like for preventing land subsidence, a method of filling the cavity with the earth and the like as it is, despite the fact that the underground cavity is easily collapsed, is adopted. Was. Also, when replacing old pipes buried underground with new pipes, it is difficult to insert new pipes if the underground cavity collapses, so leave old pipes in the ground without removing them. Here, a method has been adopted in which a new pipe having a smaller diameter is inserted into the old pipe, and cement or the like is injected into a gap between the old and new pipes to fix the new pipe to the old pipe.

[0003]

However, according to the above-mentioned method in the construction for filling the underground cavity with earth and sand for preventing land subsidence, the underground cavity is directly filled with earth and sand and the like. If the middle cavity had collapsed, it could not be filled with earth and sand, etc., or it could not be filled with earth and sand without gaps to every corner of the cavity, and there was a drawback that land subsidence could not be effectively prevented . In addition, according to the above method of replacing old pipes buried underground with new pipes, the new pipes are inserted into the old pipes, so the new pipes are smaller in size than the old pipes, and the flow rate in the pipes is reduced. However, there is a drawback that the number is reduced. The present invention provides a method of retaining the inner wall of an underground cavity, which can solve the above-mentioned conventional drawbacks, can effectively prevent land subsidence, and can prevent a reduction in the size of a new pipe when a new or old pipe is replaced. The purpose is to:

[0004]

In order to achieve the above object, a method of holding an inner wall of an underground cavity according to the present invention comprises the steps of: restoring an elastic plate to a diameter smaller than an inner diameter of an underground pipe to be removed; While retracting against the force, the retracted state is restrained, and after inserting the elastic plate into the underground pipe in the restrained state, withdrawing the underground pipe from the ground, Release the restrained state of the elastic plate, expand the diameter of the elastic plate by its restoring force, and contact the elastic plate with the inner wall of the underground cavity formed by removing the underground pipe. The inner wall of the underground cavity is held, and the operation and effect are as follows.

[0005]

In other words, the elastic plate is brought into contact with the inner wall of the underground cavity by the restoring force by the above-mentioned method and the inner wall is held, so that the collapse of the underground cavity can be prevented, and the underground cavity can be prevented. In the work of filling the soil with soil and the like for preventing land subsidence, the cavity can be filled with earth and sand without any gaps at every corner. In addition, by reducing the thickness of the elastic plate, the underground cavity can be formed in a space with the same diameter as the removed buried pipe,
As a result, in a construction in which an old pipe buried underground is replaced with a new pipe, a reduction in the size of the new pipe can be prevented.

[0006]

Therefore, when the underground cavity is filled with earth and sand, the earth can be filled without gaps at every corner of the cavity, so that land subsidence can be prevented, and when replacing the old and new pipes. Has been able to provide a method for holding the inner wall of the underground cavity, which has an advantage that the size of the new pipe can be prevented from being reduced, and the flow rate in the pipe can be prevented from decreasing.

[0007]

Next, an embodiment of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 (b) and 1 (c), first and second construction pits 2 and 12 for removing a gas pipe 1 (an example of an underground pipe) below a roadway are provided at both ends of the roadway. And a gas pipe crushing device 5 is provided in the first construction pit 2. The gas pipe crushing device 5 is a device for crushing the gas pipe 1 at regular intervals and pulling it out of the first construction pit 2 as the gas pipe 1 is pulled out.

An inner wall of an underground hole 6 (an example of an underground cavity) formed by pulling out the gas pipe 1 is held as follows.

First, a number of synthetic resin plates 3 having elasticity (an example of an elastic plate) are prepared. As shown in FIGS. 1 and 2,
Each synthetic resin plate 3 is formed to have a length, for example, about one tenth of the entire length of the gas pipe 1, and a width longer than the outer circumference of the gas pipe 1, and at both ends in the width direction. A plurality of small-diameter cord-like rings 4 are provided at positions opposing each other. Then, each synthetic resin plate 3 is rolled and shrunk in a cylindrical shape until the ends thereof overlap each other to have a smaller diameter than the gas pipe 1 against its elastic restoring force, thereby forming a cylindrical body 7. In this state, a pair of opposing cord-like rings 4 are overlapped to form one locking ring 8, and one thin wire 9 is formed on the locking ring 8 on each cylindrical body 7. Each cylindrical body 7 is connected in a line with a string 13 while being inserted through all of the stop rings 8. By inserting the fine wire 9 through the locking ring 8, the above-described contracted state is restrained. FIG.
As shown in (a), the cylindrical bodies 7 connected in a row are pushed into the underground hole 6 from the end. An expandable umbrella-shaped anchor member 10 for preventing the cylindrical body 7 from coming off is connected to the cylindrical body 7 at the tip. The cylindrical body 7
Instead of connecting everything in advance as above,
When inserting the underground hole of the cylindrical body 7, adjacent ones may be sequentially connected with the insertion. The end of the thin wire 9 is taken out into the first construction pit 2. The anchor member 10 is deployed in the second construction pit 12 and locked to the pit side wall as shown in FIG.

Next, the gas pipe 1 is pulled out, and at the same time, the fine wire 9 is drawn out to the first construction pit 2 side. The drawing speeds of the two members are set equal to each other, so that each time the gas pipe 1 is pulled out by an amount corresponding to one of the cylindrical members 7, the corresponding restrained state of the cylindrical member 7 is released. By this release, as shown in FIGS. 1 (c) and (d), the cylindrical body 7 expands in diameter by its restoring force and contacts the inner wall of the underground hole 6 formed by removing the gas pipe. Hold this inner wall.

The gas pipe 1 is crushed in a radial direction by a gas pipe crushing device 5 to be integrated with the thin wire 9 at regular intervals, and is taken out of the construction pit 2 by bending or the like at the crushed portion.

[Alternative Embodiment] There is also a construction method in which only one construction pit is formed and a part of the gas pipe is left in the ground. In such a construction method, the anchor member 10 is connected to the ground in the gas pipe. What is necessary is just to lock to the part left inside.

In a state where each elastic plate 3 is rolled and shrunk, one piece of gum tape is stuck over all of the overlapped ends to restrain the rolled and shrunk state and connect the cylindrical bodies 7 together. After each cylindrical body 7 is inserted into the underground hole 6, the restricted state may be released by sequentially peeling from the cylindrical body 7 at the tip to the first construction pit 2 side.

In the above embodiment, the length of the synthetic resin plate 3 is set to about 1/10 of the gas pipe 1, but the length ratio is not limited to this.

The underground pipe may be a water pipe or the like.

A rubber plate or the like may be used instead of the synthetic resin plate 3.

As shown in FIGS. 3A and 3B, the synthetic resin plates 3 may be connected by a thin film 11.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[0020]

[Brief description of the drawings]

FIG. 1 (a) Operational diagram of the method of retaining the inner wall of the underground cavity (b) Operational diagram of the method of retaining the inner wall of the underground cavity (c) Operational diagram of the method of retaining the inner wall of the underground cavity (d) Underground cavity Function diagram of inner wall holding method

FIG. 2 is a perspective view showing a state in which an elastic plate is wound and shrunk and adjacent elastic plates are connected to each other.

FIG. 3 (a) Perspective view of another embodiment (b) Perspective view of another embodiment

Claims (1)

(57) [Claims] 1. An elastic plate (3) having a diameter smaller than an inner diameter of an underground buried pipe (1) to be removed is retracted against its restoring force, and the retracted state is restrained. After inserting the elastic plate (3) into the underground pipe (1) in the restrained state, pull out the underground pipe (1) from the ground and release the restrained state of the elastic plate (3). The elastic plate (3) is expanded by its restoring force, and the elastic plate (3) is attached to the inner wall of the underground cavity (6) formed by removing the underground pipe (1). An underground cavity inner wall holding method for holding the inner wall of the underground cavity (6) by contacting the inner wall.