JPH10231954A - Laying method for underground embedded pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To establish a pipe laying method for an underground embedded pipe using the propulsive working method, with which there is no risk that the pipe is tightened by the ground at the time of drawing in and becomes incapable of being drawn in. SOLUTION: An iron pipe 2 furnished with a notch 5 to allow easy rupturing and stretching in the axial direction is propelled under the ground. A diameter expansion tool 4 whose front extremity is smaller than the inside diameter of the iron pipe and tail is greater than the outside diameter of the iron pipe is connected with the tip of a wire 3 threaded through the iron pipe 2, and the tip of the embedded pipe 1 is connected with the tail of the expansion tool 4. The embedded pipe 1 is laid in the iron pipe 2 buy pulling back the wire 3 while the notch 5 is cut open by a cutter blade 6. The cut iron pipe 2 is left underground to serve as a support for preventing the embedded pipe 1 from being tightened by the ground and ensures the drawing-in of the embedded pipe 1. Because this method uses low-cots iron pipe 2, does not require muddy water spouting at the time of drawing in, and does not involve collection of a propelling rod, so that it is possible to reduce the material costs, man-hours for works, and the construction period to a great extent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of laying an underground pipe for burying a gas pipe or the like in the ground by a propulsion method.

[0002]

2. Description of the Related Art FIG. 3 shows an outline of a conventional propulsion method for burying a city gas supply pipe or the like underground without digging. Nominal diameter 300 by propulsion method
buried pipe 11 with a small diameter of 100 mm or less and a length of about 100 m,
0.3- in underground soils such as cohesive, gravel, or sandy soils
When laying at a depth of about 4.5 m, the following 2
The process method has already been put to practical use.

In the first step of the two-step propulsion method, of the shafts 12 and 13 excavated at both ends of the buried section, a metal shaft is formed from the shaft 12 on the side opposite to the drawing side toward the shaft 13 on the drawing side. This is a rod propulsion step of propelling the propulsion rod 14 into the ground. The propulsion rod 14 has a diameter of 30 to 60 m.
m and a length of about 0.5 to 3 m are sequentially added to the root on the starting side, and enter the ground with the propulsion head mounted on the tip first.

[0004] In a second step, the propulsion head 1 mounted on the tip of the propulsion rod 14 that has reached the shaft 13 on the retracted side is provided.
The joint 17 is hooked on the hook 16 of No. 5. This is a drawing step of pulling the buried pipe 11 connected to the joint 17 into the ground by pulling the propulsion rod 14 back toward the shaft 12. The buried pipe 11 is made of a synthetic resin such as polyethylene and has flexibility. Muddy water is blown out from the tip of the propulsion rod 14 to loosen the ground and lay the buried pipe 1
Burial pipe 1 while cutting and expanding the ground to the diameter of 1
1 is retracted.

[0005]

However, the above-mentioned conventional propulsion method has many problems to be solved as follows. A first problem is that in the second step of drawing in a buried pipe, the ground may tighten the buried pipe, so that the buried pipe may not be able to be drawn in. This problem is particularly serious when the ground is sandy.

The second problem is that the cost of the propulsion rod is increased because the propulsion rod is subjected to a quenching treatment for maintaining hardness and is required to have durability so that it can be used repeatedly. . The unit price of the propulsion rod is about 30,000 yen / m. If the laying section is 100 m, the total cost is 3 million yen.

[0007] The third problem is that since muddy water is used to loosen the ground, it is necessary to prepare a muddy water storage tank and a muddy water spraying device, and a troublesome operation for treating muddy water accumulated in the shaft is required. It is to accompany.

A fourth problem is that, in order to repeatedly use expensive propulsion rods, it is necessary to remove the propulsion rods one by one when pulling the buried pipe, clean and collect the propulsion rods. Since most of the working time required for retraction is collected by the propulsion rod, the laying work requires a lot of time and effort, which increases the cost and the construction period.

[0009] An object of the present invention is to prevent the buried pipe from being tightened to the ground in the second step so that it cannot be retracted,
Especially in the case of sandy ground, underground pipes that can be pulled in reliably and that can shorten the laying period without using expensive propulsion rods and without collecting propulsion rods that require a lot of work time It is to provide a laying method.

[0010]

SUMMARY OF THE INVENTION According to the present invention, a metal pipe provided in advance so that an easily breakable portion extends in the axial direction is propelled underground, and a wire is passed through the metal pipe from one end. At the tip of the wire protruding from the other end of the metal tube, an outer diameter at the front end is smaller than the inner diameter of the metal tube, and at the rear end the outer diameter is enlarged and becomes larger than the outer diameter of the metal tube. Connect the tip of the pipe to be buried at the rear end of the expanding tool, pull back the wire from one end side of the metal pipe, and cut open the metal pipe from the other end side with the expanding tool, An underground pipe laying method characterized by laying a pipe to be buried in a metal pipe. According to the present invention, the metal pipe provided so that the easily breakable portion extends in the axial direction is propelled into the ground. At the tip of the wire rod that is passed through the metal tube from one end and protrudes from the other end, the outer diameter of the front end side is smaller than the inner diameter of the metal tube,
At the rear end side, a diameter-enlargement tool whose outer shape is enlarged and becomes larger than the outer diameter of the metal tube is connected. The front end of the pipe to be buried is connected to the rear end of the expanding tool, and the wire is pulled back from one end of the metal pipe. The wire is pulled back and laid in the metal pipe while the metal pipe is cut open from the other end by the diameter expanding tool.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a connection state of a distal end portion at the start of laying of a buried pipe 1 by a laying method according to an embodiment of the present invention. The iron pipe 2 is propelled from the opposite side of the entrance of the laying section and reaches the entrance through the iron pipe 2 which is a metal tube, and is passed through the end opposite to the entrance by a wire passing tool. Wire 3 such as a wire projecting from
The front end of the diameter-enlargement tool 4 is connected to the front end portion. The distal end of the buried pipe 1 is connected to the rear end of the diameter expanding tool 4. The buried tube 1 is made of a flexible synthetic resin such as polyethylene.

The thickness of the iron pipe 2 is about 1 mm, and the section line Y
As shown in FIG. 2, which is a cross section as viewed from -Y, a cut 5 extending in the axial direction is provided in advance at one location in the circumferential direction of the cross section so as to be easily broken by using a grinder or the like. The diameter-enlarging tool 4 is formed such that the outer diameter at the front end is smaller than the inner diameter of the iron pipe 2, and the outer diameter is enlarged at the rear end side to be larger than the outer diameter of the iron pipe 2, and the cut 5 of the iron pipe 2 is provided. An incision blade 6 is provided at a portion corresponding to the location.

When the wire 3 is pulled back in the direction indicated by the arrow 7, the small-diameter side of the front end enters the iron pipe 3, the blade 6 cuts the cut 5 of the iron pipe 2, and the diameter expanding tool 4 moves to the rear end side. The iron pipe 2 is pushed open by the larger outer diameter and proceeds while expanding the diameter, and the buried pipe 1 is drawn into the iron pipe 2 and laid. Since the wire 3 needs a pulling force of about 2 ton to be pulled back, the wire 3 is pulled back by winding the winch. Since the iron pipe 2 is left without being collected and serves as a support for preventing the ground such as sand ground from tightening the buried pipe 1, the buried pipe 1 can be reliably laid in the ground in the laid section.

The present invention can be applied not only to the laying between the burials for supplying city gas but also to the underground pipes for other uses.

[0015]

As described above, according to the present invention, the buried pipe is pulled into the metal pipe which has been cut open and expanded, and the metal pipe is left as a support for preventing the ground sand or the like from tightening the buried pipe. As a result, the situation where the ground cannot be pulled in due to the ground tightening is prevented, and the buried pipe is reliably pulled in.

As a metal tube, a commercially available iron tube or the like, which is easily available, is used after being easily broken, so that the cost is lower than that of a conventional propulsion rod that is hardened. Further, since it is not necessary to cut or expand the ground by injecting muddy water when the buried pipe is pulled in, there is no need to prepare a muddy water storage tank or a muddy water spraying device, and the muddy water treatment operation is also unnecessary. Furthermore, since the propulsion rods are not collected, the labor for retracting the propulsion pipe is greatly reduced, and the laying period can be shortened.

As described above, according to the present invention, an inexpensive metal pipe can be used, the number of working steps is reduced, the burying period is shortened, and the buried pipe can be laid reliably.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line YY of FIG. 1;

FIG. 3 is a cross-sectional view schematically showing a state in which an underground pipe is retracted by a conventional propulsion method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Buried pipe 2 Iron pipe 3 Wire rod 4 Enlarger tool 5 Cut 6 Blade

Claims (1)

[Claims] 1. A metal pipe provided with an easily breakable portion extending in the axial direction in advance, is propelled into the ground, a wire is passed through the metal pipe from one end, and the metal pipe is inserted from the other end of the metal pipe. At the tip of the protruding wire, connect an expanding tool whose outer diameter at the front end is smaller than the inner diameter of the metal pipe, and whose outer diameter is larger at the rear end and larger than the outer diameter of the metal pipe. Connect the tip of the pipe to be buried to the rear end, pull back the wire from one end of the metal pipe, cut the metal pipe from the other end with a diameter expander, and place the pipe to be buried in the metal pipe. An underground pipe laying method characterized by laying.