JP2023177170A - Earth retaining tube for forming reach shaft and underground tube construction method using thereof - Google Patents

Abstract

To provide an earth retaining tube for forming a reach shaft and an underground tube construction method, which allows a wide work space in a tube without using a large tubular member and does not impair the water stop properties of water stop rubber.SOLUTION: An earth retaining tube 1 for forming a reach shaft according to the present invention includes a tubular member 2, a plurality of sheets of water stop rubber 3 provided overlappingly on an inner surface of the tubular member 2, a protection sheet 4 provided on an inner surface of the tube in the innermost water stop rubber of the tubular member 2, a water stop rubber support member 5 when supporting the water stop rubber 3 and the protection sheet 4, and a soil cutting member 10 provided at a tip of the tubular member 2. A tube insertion hole 9 into which a propulsion tube enters is formed in the water stop rubber 3.SELECTED DRAWING: Figure 16

Description

The present invention relates to a construction method for constructing underground pipes for laying underground pipes laterally in the soil.

When laying underground pipes such as water and sewage pipes or gas pipes laterally in the soil, if there are no obstacles on the ground, it is possible to dig a trench above the ground and lay the buried pipes. However, if you are trying to run a buried pipe, and if a waterway or fence has already been laid above the section, if you try to dig a trench from the ground, you must first remove those obstacles and begin laying the buried pipe. After the process is completed, the removed items must be rebuilt, which increases the amount of work, cost, and time required. Furthermore, if water is flowing in a waterway, it may not be possible to stop the waterway.

Therefore, there is a construction method in which a propulsion machine is installed in a vertical shaft (starting shaft) provided in advance, and the pipe is propelled laterally from inside the starting shaft to construct an underground pipeline. By doing this, it is possible to form a horizontal underground conduit without touching waterways, walls, etc. on the ground. However, in order to connect the other end of the buried pipe installed laterally to another pipe, a vertical shaft (reaching shaft) must be dug on the other end side as well, and the connection work must be performed inside the reaching shaft. . To this end, water-stopping measures must be taken to prevent groundwater and soil from entering the space where these works are performed. Therefore, a chemical injection technique is used in which a hardening agent is injected around the reaching hole in advance (Patent Document 1).

The invention according to Patent Document 2 includes a cylindrical guide pipe body, a side hole provided in the side wall near the tip of the guide pipe body, and an elastic sheet provided from the outside of the guide pipe body so as to cover the side hole. An earth retaining guide pipe with an earth retaining guide pipe is inserted vertically into the ground to form a reaching hole, and the propulsion pipe is propelled laterally from the starting hole, and the tip of the propelling pipe is pressed against the elastic sheet of the earth retaining guide pipe and inserted into the horizontal hole. The elastic sheet is inserted to form a water stop between the propulsion tube and the horizontal hole, and a hole is made in the elastic sheet at the tip of the propulsion tube to connect the retaining guide pipe and the propulsion tube.

In the invention according to Patent Document 3, the earth retaining pipe for forming a reaching shaft includes a tubular member, a water stop rubber, a water stop rubber support member provided inside the tubular member, and a soil cutting member provided at the tip of the tubular member. The waterproof rubber has a tube insertion hole formed therein.

Japanese Patent Application Publication No. 2001-207783 JP 2005-282315 Publication Patent Publication JP 2014-37733 Publication Patent Publication

When laying a buried pipe that runs horizontally underground, it is effective to drive the propulsion pipe horizontally from the starting shaft in order to avoid obstacles such as waterways above it. Water stoppage measures must be taken to prevent groundwater and soil from entering the work space. However, ground improvement by chemical injection as described in Patent Document 1 is an auxiliary method, and is a temporary construction method that is used to improve ground that contains a large amount of permeable groundwater or water channels. For construction sites where water leakage is a concern, chemical injection alone will not provide a sufficient water stoppage effect.

With the earth retaining guide pipe and underground conduit construction method of Patent Document 2, it is possible to form an underground conduit while preventing groundwater and earth from entering the work space, even without the need for workers to enter the tunnel. can. The elastic sheet provided to cover the side hole prevents groundwater, earth and sand from entering the tunnel before it is connected to the propulsion pipe, and the elastic sheet is installed to cover the side hole when the propulsion pipe is inserted into the retaining guide pipe. forms a water stop part, which can prevent groundwater and earth from entering the tunnel or propulsion pipe during construction. However, since the earth retaining guide pipe of Patent Document 2 has a rubber sheet attached to the outside of the guide pipe main body, the protruding portion acts as a resistance to insertion into the ground. Insertion becomes difficult, especially in hard ground. Additionally, there are no holes in the rubber sheet, and the holes can be made using the tip of the propulsion tube, but it has been found that it is actually difficult to punch through the highly elastic rubber sheet.

In the earth retaining pipe for forming a reaching shaft of Patent Document 3, a pipe insertion hole is formed in the water stop rubber, so there is no need to hollow out the water stop rubber with the propulsion pipe, and the water stop state can be easily achieved while connecting the propulsion pipe. can be realized. The mounting position of the water stop rubber is set so that the tip of the propulsion tube does not hit the water stop rubber until the hole is completed in the hole cover plate. By stopping the rotation of the propulsion tube and allowing the propulsion tube to enter, damage to the water stop rubber is prevented. However, the propulsion tube must penetrate deeply into the tubular member. Therefore, when the propulsion tube finishes entering, the distance from the tip of the propulsion tube to the inner wall on the back side of the tubular member becomes shorter. When passing a horizontal buried pipe into the propulsion pipe and connecting it to a vertical buried pipe introduced from above the reaching shaft, the space for performing this connection work becomes small. If sufficient space is to be obtained, it is necessary to use a tubular member with a large diameter, which increases the cost of materials and driving operations. Also, if the site does not have enough space, large tubular members cannot be used.

Furthermore, when the propulsion tube enters the hole in the waterstop rubber, there is a risk that the tip of the propulsion tube may damage the waterstop rubber and impair the waterstopping performance.

The present invention provides an earth retaining pipe for forming a reaching shaft and an underground pipe construction method that can provide a wide working space within the pipe without using a large tubular member and do not impair the water-stopping properties of water-stopping rubber. The purpose is to

In order to solve the above-mentioned problems, the earth retaining pipe for forming a reaching shaft of the present invention includes a tubular member, a plurality of sheets of water-stop rubber provided in layers on the inner surface of the tubular member, and a water-stop rubber on the innermost side of the tubular member. It has a protective sheet provided on the inner surface of the pipe, a water stop rubber support member that supports the water stop rubber and the protection sheet, and a soil cutting member provided at the tip of the tubular member, and the water stop rubber has a water stop rubber support member that supports the protection sheet, and a soil cutting member that is provided at the tip of the tubular member. A hole is formed. The water stop rubber has an outer water stop rubber that contacts the inner surface of the tubular member and an inner water stop rubber that is provided inside the outer water stop rubber, and the inner water stop rubber may be thicker than the outer water stop rubber. preferable. The tubular member has a cylindrical tube main body, a hole provided on the side surface of the main body, and a hole cover member provided on the outer surface of the main body to cover the hole, and the water stop rubber is provided on the inner surface of the hole cover member. It is preferable that it be attached to.

Furthermore, the underground conduit construction method of the present invention is an underground conduit construction method that uses the above-mentioned earth retaining pipe for forming a reaching hole, and the earth retaining pipe for forming a reaching hole is driven perpendicularly into the ground while rotating. From the starting shaft side, a sheath tube with a soil cutting member at the tip and an outer diameter larger than the inner diameter of the water-stopping rubber tube insertion hole is sent toward the destination shaft while rotating. Bring the sheath pipe into contact with the earth retaining pipe for forming the reach hole, cut the hole covering member at the tip of the sheath pipe, insert the sheath pipe into the pipe insertion hole of the water stop rubber, and form a water stop part with the water stop rubber. The sheath pipe is connected to the earth retaining pipe for forming the reaching shaft, and the main pipe is sent from the starting shaft side to the reaching shaft through the sheath pipe to form an underground conduit from the starting shaft side to the reaching shaft.

In the earth retaining pipe for forming a reaching shaft of the present invention, there is sufficient space within the pipe, and connection work between horizontal and vertical buried pipes can be easily performed. Even when the sheath tube, which is a propulsion tube, enters the hole in the water stop rubber while expanding it, the water stop property of the water stop rubber is not impaired.

FIG. 3 is a front view showing a retaining pipe for forming a reaching shaft. It is a left side view of the same. It is a sectional view taken along the line AA. It is a BB sectional view of the same. It is a sectional view taken along the line CC. It is a front view of a hole cover board. FIG. It is a developed view of water stop rubber. It is a developed view of a protective sheet. FIG. 3 is a developed view of the water stop rubber support member. It is a front view of the same. FIG. FIG. 7 is a developed view of another example of the water stop rubber support member. FIG. 2 is a conceptual diagram schematically showing an underground pipe construction method. It is a flowchart showing the process of the underground pipe construction method. FIG. 3 is a cross-sectional view showing the state of the propulsion tube. It is a DD sectional view of the same.

Embodiments for carrying out the present invention will be described in detail based on the drawings. Figure 1 is a front view showing the earth retaining pipe for forming a reaching shaft, Figure 2 is a left side view of the same, Figure 3 is a sectional view taken along line AA, Figure 4 is a sectional view taken along line BB, and Figure 5 is a sectional view taken along line CC. It is. The earth retaining pipe 1 for forming a reaching shaft includes a tubular member 2, a water stop rubber 3, a water stop rubber 3 provided inside the tubular member 2, a protective sheet 4 that protects the water stop rubber 3, and a water stop rubber support. It has a member 5.

The tubular member 2 is a cylindrical member that forms the main body of the earth retaining pipe for forming a reach shaft of the present invention. Although it can be formed from a cylindrical steel pipe or the like, in this example, a hole 6 is provided in a part of the side surface, and a hole cover plate 7 is further attached to cover the hole. In this case, the hole cover plate 7 is also formed into a tubular member. In this example, a cylindrical tube 8 having sufficient strength is used as the main body of the tubular member 2, and here a steel tube is used. When constructing an underground passage, a sufficient inner diameter is required to introduce a vertically buried pipe into the tubular member 2 and connect it with a horizontally buried pipe within the tubular member 2, but as described later, it is necessary for workers to reach Since these operations can be carried out without going into a tunnel, a fairly small pipe can be used.Moreover, according to the present invention, a sufficient working space can be obtained inside the pipe, and the work space of 500 mm, which has not been used until now, can be It can now be applied to pipes with smaller diameters. For example, it is preferable that the outer diameter is selected within the range of 400 mm or more and 800 mm or less, and the length is selected within the range of 800 mm or more and 1000 mm or less. In particular, in this example, a steel pipe (φ400 steel pipe) with an outer diameter of 406.4 mm and a thickness of 6.4 mm is used. A rectangular hole 6 is made on the side surface of this steel pipe at a position where the water stop rubber 3 is provided. This hole 6 is oriented in the direction in which the propulsion pipe enters during construction, and the propulsion pipe passes through this hole. However, this hole 6 is formed larger than the outer shape of the propulsion tube.

A hole cover plate 7 is provided outside the hole 6 to cover the hole 6. FIG. 6 is a front view of the hole cover plate, and FIG. 7 is a plan view thereof. The hole cover plate 7 is wide enough to close the hole 6, and is made of a rectangular steel plate bent to have a curved surface along the outer surface of the cylindrical member 8. It is made of a material that has a certain degree of strength but is weaker than the cylindrical member 8. Here, a steel plate with a thickness of 4.5 mm, which is thinner than the cylindrical member 8, is used.

FIG. 8 is a developed view of the waterproof rubber. A rectangular rubber sheet is used as the water stop rubber 3. A tube insertion hole 9 is formed in the center of the water stop rubber 3. The diameter of this tube insertion hole 9 is slightly smaller than the diameter of the propulsion tube (sheath tube) to be inserted. For example, when the outer diameter of the sheath tube is 250 mm, the diameter of the tube insertion hole 9 of the water stop rubber 3 is about 200 mm.

A plurality of water stop rubbers 3 are provided one on top of the other. Here, two sheets are stacked: an outer water stop rubber 3a that is in contact with the inner surface of the tubular member 2, and an inner water stop rubber 3b that is provided inside the outer water stop rubber 3a. A lubricant is applied between the outer water stop rubber 3a and the inner water stop rubber 3b to reduce friction between the two water stop rubbers. The inner water stop rubber 3b is thicker than the outer water stop rubber 3a, and in this example, the thickness of the outer water stop rubber 3a is 5 mm, and the thickness of the inner water stop rubber 3b is 10 mm. By making the inner water stop rubber 3b thick in this manner, sufficient water stop performance can be obtained with only the inner water stop rubber 3b. On the other hand, it contributes to water stoppage of the outer waterstop rubber 3a, and also has a function of protecting the inner waterstop rubber 3b when the sheath pipe enters.

FIG. 9 is a developed view of the protective sheet. It has the same rectangular shape as the waterproof rubber 3, but there are no holes. It is attached to the inner surface of the water stop rubber 3, that is, the surface facing inward of the tubular member 2. It is preferable that the protective sheet 4 has appropriate elasticity, and a sheet with a smooth surface and a small coefficient of friction is used. This reduces the resistance caused by earth and sand when rotating and driving the rubber into the soil, effectively preventing damage to the water stop rubber. In this example, a sheet of glass fiber fabric coated with silicone resin is used. The thickness of this sheet is 0.3 mm, and plain weave glass fiber fabric is used.

The water stop rubber support member 5 is a member for supporting the water stop rubber 3 and the protective sheet 4 inside the tubular member 2. FIG. 10 is a developed view of an example of the waterproof rubber support member, FIG. 11 is a front view thereof, and FIG. 12 is a plan view thereof. In this example, the water stop rubber support member 5 is an integrally formed bent plate-like member, and is made of a steel plate with a thickness of 4.5 mm. In the developed view, it is a rectangle having the same outer periphery as the outer periphery of the water-stop rubber 3 and the protective sheet 4, but there is a large rectangular cutout inside, giving it the shape of a rectangular frame. The waterproof rubber support member 5 is formed by bending this into a curved surface that roughly follows the inner surface of the hole cover plate 7.

The hole cover plate 7, the water stop rubber 3, the protection sheet 4, and the water stop rubber support member 5 are provided with bolt holes 12 along the outer periphery, which are aligned with each other.

The hole cover plate 7 is attached to the outer surface of the tube by welding so as to close the hole 6 of the cylindrical member 8 (the main body of the tubular member). Then, the water stop rubber 3 is attached to the inner surface of the hole cover plate 7. At this time, the tube insertion hole 9 of the water stop rubber 3 is filled with a lubricant 11. A special silicone bond is applied to the inner surface of this waterproof rubber 3 for adhesion to the protective sheet, and the protective sheet 4 is laminated and pasted on top of it. In this way, the protective sheet 4 is firmly attached to the waterproof rubber 3 and integrated. Furthermore, a water stop rubber support member 5 is stacked on the inside thereof. A bolt is passed through the bolt through hole 12 from the outside of the hole cover plate 7, and a nut is attached to the inside and tightened. As a result, the outer circumferences of the waterproof rubber 3 and the protective sheet 4 are fixed to the inner surface of the hole cover plate 7. Note that, after this, the head of the nut is welded to the hole covering plate 7, and further the head of the nut is ground down using a grinder, thereby making it possible to reduce the protrusion of the tubular body to the outside.

FIG. 13 is a developed view of another example of the waterproof rubber support member. In this figure, the water stop rubber support member 5 is separated into a pair of horizontal strip plates 5a and a pair of vertical strip plates 5b. When all these are collected, a shape similar to the example shown in FIG. 10 is obtained. By dividing into four parts in this way, manufacturing becomes easier. In addition, in the case of a one-piece member, all the bolt holes 12 must be accurately aligned with the bolt holes of the waterproof rubber 3 and the protective sheet 4, but this may be difficult, but in this example Body parts can be positioned independently of each other, facilitating alignment.

An example in which the tubular member 2 is composed of the cylindrical member 8 and the hole cover plate 7 has been described above. By using the hole covering plate 7 which is thinner than the cylindrical member 8, there is an advantage that cutting by the sheath pipe and entering into the tubular member 2 are facilitated. The water stop rubber 3 and the protective sheet 4 are arranged so as to fit into the hole 6 of the cylindrical member 8.
Unlike this example, the tubular member 2 can also be formed of only the cylindrical member 8. In this case, the water stop rubber 3 and the protective sheet 4 will be attached to the inner surface of the cylindrical member 8.

At the lower end of the tubular member 2, a plurality of highly hard cutting claws called metal crowns are provided as the soil cutting member 10. This soil cutting member 10 enables the earth and sand to be effectively cut, making it easier to insert the tubular member 2 into the ground.

Next, we will explain the construction method for underground pipes using earth retaining pipes for forming reaching shafts. FIG. 14 is a conceptual diagram schematically showing the underground pipe construction method, and FIG. 15 is a flowchart showing the steps of the underground pipe construction method. This underground pipe construction method uses a propulsion method in which sheath pipes are fed horizontally from a starting shaft to a destination shaft. Such propulsion methods have already been implemented and are disclosed in JP-A Nos. 2006-193983 and 2006-214086.

The starting shaft 20 is formed by a well-known method such as a manhole. A propulsion machine 21 for laterally driving the propulsion tube x into the ground from the launch shaft 20 is installed in the launch shaft 20.

On the other hand, the reaching shaft formation retaining pipe 1 is vertically inserted into the position where the propulsion pipe x should reach, thereby forming a vertical shaft that will become the reaching shaft. Here, in the case of soils such as sand and gravel that have a large hydraulic conductivity and are not self-supporting, soils with pressurized water, ground with strong groundwater flow, or ground where groundwater blows up from below vertical buried pipes, it is necessary to In addition to using the formation retaining pipe 1, auxiliary construction methods such as chemical injection will also be implemented. If there is water leakage, the filling material will be diluted with groundwater etc. and the strength of the filling material will not be ensured when pouring the filling material between the propulsion pipe x and the buried pipe 24, which will be described later. These problems can be prevented by using auxiliary construction methods such as
The earth retaining pipe 1 for forming a reaching shaft is driven by a propulsion machine 23 for forming a vertical shaft. The propulsion machine 23 grips the earth retaining pipe 1 for forming an reaching hole and inserts it into the ground while applying rotation to the earth retaining pipe 1 for forming an reaching hole. Since there are no protrusions on either the outer or inner surface of the earth retaining pipe 1 for forming the reach hole, there is little resistance to rotation. Even so, the earth and sand inside the earth retaining pipe 1 for reaching the tunnel formation comes into contact with the inner surface of the tubular member 2, but since the inner surface of the water stop rubber 3 is covered with the protective sheet 4, it will not be damaged by contact with earth and sand. Prevented. Since the soil cutting member 10 is provided at the tip of the soil retaining pipe 1 for forming a reach hole, the soil is effectively cut by the rotation of the soil cutting member 10. Thereby, even in hard soil, the earth retaining pipe 1 for forming the reaching hole can be built.

Once the earth retaining pipe 1 for forming the reach tunnel is inserted into the ground to some extent, a steel pipe of the same diameter is added on top of it by welding or the like, and the pipe is further erected. In addition, the earth and sand inside the steel pipes will be removed using auger removal, vacuum suction, etc. In this way, the reaching hole 22 is formed. The pipe insertion hole 9 of the water stop rubber 3 of the earth retaining pipe 1 for forming the reaching shaft is oriented in the direction of the starting shaft 20. If necessary, a small amount of cement liquid may be poured into the reaching hole 22 to harden the bottom surface to prevent groundwater and earth from flowing in from the bottom surface.

Once the reaching hole 22 is formed, the propulsion tube x is sent out from the starting hole 20 toward the tube insertion hole 9 of the earth retaining pipe 1 for forming the reaching hole. The tip of the propulsion tube x is also provided with a plurality of high-hardness cutting claws called metal crowns, which are shaped like a saw. This propulsion tube x is advanced to the reaching shaft 22 while being rotated. The earth and sand in the propulsion tube x is discharged by suction from the launch shaft 20. When the tip of the propulsion pipe x that has reached the earth retaining pipe 1 for forming a landing shaft reaches the side surface of the tubular member 2, a hole is made in the side surface. A hole is formed in the hole cover plate 7 by pressing the tip of the saw-shaped propulsion tube x against the hole cover plate 7 while rotating. Here, since the hole cover plate 7 is also in the shape of a cylindrical shell, the tip of the propulsion tube x first contacts the hole cover plate 7 at its upper and lower parts. Cutting of the hole cover plate 7 starts from this point. When the hole cover plate 7 is cut to the inner surface at this location, the tip of the propulsion tube x comes into contact with the water stopper rubber 3a on the outside. However, at this point, the drilling of holes in the hole cover plate 7 is not completed. The drilling is completed by continuing to rotate and advance the propulsion tube x and cutting the hole covering plate 7 to the left and right.

FIG. 16 is a sectional view showing the state in which the propulsion tube has arrived, and the figure shows the state in which the propulsion tube x enters from the right side. Further, FIG. 17 is a sectional view taken along the line DD. Until the hole drilling is completed, the pipe continues to enter the tube insertion hole 9 of the water stop rubber 3. Since the lubricant filled in the tube insertion hole 9 comes out onto the surface of the water stop rubber 3, the friction between the propulsion tube x and the water stop rubber 3 is alleviated. However, since the saw-shaped tip of the propulsion tube x comes into contact with it while rotating, there is a possibility that cracks will occur in the outer water stop rubber 3a that comes into contact with it. This crack propagates in the thickness direction of the outer water stopper rubber 3a and may even reach the opposite surface. However, the inner water stopper rubber 3b is a sheet independent from the outer waterstop rubber 3a, and cracks will not progress to the inner waterstop rubber 3b. Therefore, the outer water stopper rubber 3a also acts as a protective sheet for the inner waterstop rubber 3b.

Since the tube insertion hole 9 is smaller than the outer shape of the propulsion tube x, the propulsion tube x enters while pushing the rubber sheet near the tube insertion hole 9 into the inner side of the earth retaining pipe 1 for forming the reaching hole. Since the protective sheet 4 is a plain weave glass fiber fabric that can be easily cut with a knife, it is pierced by the tip of the propulsion tube x. Then, a portion of the rubber sheet near the tube insertion hole 9 is bent to wrap around the side of the propulsion tube x, and that portion becomes a water stop portion. In this way, a water stop part can be formed simply by entering the propulsion pipe x into the earth retaining pipe 1 for forming the reaching hole, and groundwater and earth and sand can be drawn into the earth retaining pipe 1 for forming the reaching hole from the entry point of the propelling pipe x. Inflow is prevented.

Once the water has entered deep enough to form a water stop, the rotation and advancement of the propulsion tube x is stopped. Since the water stop rubber 3 is attached along the inner surface of the tubular member 2, a long distance remains between the tip of the propulsion tube x and the inner surface of the tubular member 2, and a wide working space is secured. In this way, the propulsion pipe x and the reaching shaft 22 are connected.

Next, buried pipes (main pipes) 24 and 25 are passed from two directions, vertically and horizontally, through the earth retaining pipe 1 for forming the reach hole and the propulsion pipe x. A horizontal buried pipe 24 is introduced from the starting shaft 20 through the propulsion pipe x to the reaching shaft forming earth retaining pipe 1. A vertical buried pipe 25 is introduced from above the reaching hole 22. A drop pipe bent at 90 degrees is provided at the lower end of the vertical buried pipe 25, and is connected to the tip of the horizontal buried pipe 24. Although the ends of these two buried pipes 24 and 25 are connected within the earth retaining pipe 1 for forming the reaching pit, the work can be done without entering the pipe. A worker above the reaching shaft 22 holds the upper side of the vertical buried pipe 25, adjusts the position and direction of its lower end, pushes out the horizontal buried pipe 24 from the starting shaft 20, and buries its tip vertically. Connect to the lower end of tube 25. A large working space is required for this work, but according to the present invention, the necessary working space can be obtained even with a thin earth retaining pipe for forming a reaching hole.

After the buried pipes 24 and 25 are connected to each other, a filler is introduced from above the reach hole 22 and poured between the propulsion pipe x and the buried pipe 24. On the starting shaft 20 side, the end of the propulsion pipe x is covered, and the space between the propulsion pipe x and the buried pipe 24 is sealed. When the filler is completely filled, stop adding the filler. Note that it is preferable that the propulsion tube x is inserted to a certain extent so as to protrude into the interior of the tubular member 2. In this way, by connecting the tubular member 2 and the propulsion pipe x as one body and solidifying the connection by inserting a filler, the tubular member 2 and the propulsion pipe Since they move as one unit, no force is applied that would deform the connection between the buried pipes 24 and 25. This prevents the connecting portions of the buried pipes 24 and 25 from being damaged and causing water leakage due to vibrations such as earthquakes.

In this way, an underground conduit extending from the upper part of the arrival shaft 22 to the starting shaft 20 is formed. It does not affect construction when there is an obstacle such as a waterway between the starting shaft 20 and the reaching shaft 22, or on any ground. Furthermore, since there is no need for a worker to enter the reaching shaft 22, the construction can be carried out even in a small vertical shaft where no one can enter.

1. Retaining pipe for forming a reach hole 2. Tubular member 3. Water stop rubber 4. Protective sheet 5. Water stop rubber support member 6. Hole 7. Hole cover plate 8. Cylindrical member (main body of tubular member)
9. Pipe insertion hole 10. Soil cutting member 11. Lubricant 12. Bolt through hole 20. Launch shaft 21. Propulsion machine 22. Reaching hole 23. Propulsion machine for shaft formation24. Horizontal buried pipe25. Vertical buried pipe x. Propulsion tube (sheath tube)

Claims (4)

A tubular member, a plurality of sheets of waterproof rubber layered on the inner surface of the tubular member, a protective sheet provided on the inner surface of the tube in the innermost waterproof rubber of the tubular member, and supports the waterproof rubber and the protective sheet. A soil retaining pipe for forming an access hole, which has a water-stop rubber support member and a soil-cutting member provided at the tip of the tubular member, and the water-stop rubber has a pipe insertion hole formed therein. The water stop rubber has an outer water stop rubber in contact with the inner surface of the tubular member, and an inner water stop rubber provided inside the outer water stop rubber, and the inner water stop rubber is thicker than the outer water stop rubber. 1. The earth retaining pipe for forming a reaching pit according to 1. The tubular member has a cylindrical tube main body, a hole provided on the side surface of the main body, and a hole cover member provided on the outer surface of the main body to cover the hole, and the water stop rubber is provided on the inner surface of the hole cover member. The earth retaining pipe for forming an access hole according to claim 1 or 2, which is attached to. An underground conduit construction method using the earth retaining pipe for forming a reaching hole according to claim 3, in which the earth retaining pipe for forming a reaching hole is driven perpendicularly into the ground while rotating to form a reaching hole,
From the starting shaft side, the sheath tube, which has a soil cutting member at its tip and whose outer diameter is larger than the inner diameter of the water-stopping rubber tube insertion hole, is sent toward the destination hole while rotating.
While rotating the sheath pipe, bring the sheath pipe into contact with the earth retaining pipe for forming the reach hole, and cut the hole covering member with the tip of the sheath pipe,
Insert the sheath pipe into the pipe insertion hole of the water stop rubber, form a water stop part with the water stop rubber, and connect the sheath pipe to the earth retaining pipe for forming the reaching hole.
An underground conduit construction method in which the main pipe is sent from the starting shaft side to the destination shaft through a sheath pipe, forming an underground conduit from the starting shaft side to the destination shaft.

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