JPH0323794B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention aims to provide a method for reducing the frictional resistance between soil, etc. and buried pipes when removing buried pipes such as gas pipes and water pipes. It is something.

<Conventional Technology> Buried pipes such as gas pipes and water pipes may need to be removed due to aging or other reasons, such as requiring replacement with new pipes.

This type of construction is normally carried out using the trenchless method, but in recent years it has become desirable to perform trenchless construction due to traffic conditions and other reasons.

When removing a buried pipe without excavation, a vertical shaft is formed at both ends of the removed section, both ends of the buried pipe are exposed and cut at this point, and the pipe is pulled or pushed out from within the shaft to be removed. Become. However, in this case, the frictional resistance between the removed pipe and the soil is extremely large, and a large amount of force is required to pull it out or push it out, so there are restrictions on the pipe diameter and removal distance, making it impossible to remove large diameter pipes or long distances. Ta.

<Summary of the invention> The present invention has been made in view of the above points, and
The purpose of this invention is to provide a method for reducing the frictional resistance of buried and removed pipes.

In the present invention, first, vertical shafts are formed at both ends of the buried removal pipe to be removed, and both ends are exposed and then cut. Then, a slit is formed in the axial direction within the buried and removed pipe. The length of this slit may be the entire length of the pipe to be removed, or may be a part of it. Next, a fluid such as water is pressurized into the slit-formed removal pipe to expand the diameter of the pipe. The fluid is then discharged to reduce the diameter of the tube. Pressing in and discharging the fluid may be repeated multiple times. This diameter expansion and diameter reduction breaks the adhesion between the removed pipe and the soil, reducing frictional resistance. Furthermore, although some fluid leaks from the slit when fluid is press-fitted, this leaked fluid also contributes to reducing frictional resistance.

<Examples> The present invention will be described below based on illustrated examples.

As shown in Fig. 1, vertical shafts A and B are dug to expose both ends of the buried removal pipe X, which are then cut. Then, a slit is formed in the axial direction of the removal tube X. Various methods can be used to form the slits, but in this embodiment, an excavator 5 is used as shown in FIG. This excavator 5 is a device already proposed by the applicant in Japanese Patent Application Laid-Open Nos. 11297-1982 and 122698-1989. A pilot pipe 50 is attached to the excavator 5, and a cutting torch 51 is provided at the tip of the pilot pipe 50. The pilot tube 50 is movable forward and backward and rotatable. This excavator 5 is installed in one shaft A, a pilot pipe 50 is inserted into a removal pipe X, and a slit is formed with a cutting torch 51. FIG. 3 shows a state in which one slit 1 is formed. This slit 1 weakens the rigidity of the tube X in the circumferential direction, making it easier to expand and contract in the radial direction.

Even if the slit 1 is provided over the entire length of the tube
It may be provided in a portion. Moreover, the number is also arbitrary.

After the slit 1 is provided, both ends of the removal tube X are sealed with lids 2, 2, as shown in FIG. 4, and fluid is pressurized into the tube X from the fluid injection device 3. In this embodiment, water is used as this fluid. By pressurizing the fluid in this way, the tube
Expand the diameter. Next, the pressurized fluid is discharged, and the diameter is reduced to the original diameter again. By this diameter expansion and diameter reduction, the adhesion between the pipe X and the soil is broken and the frictional resistance is reduced.

Note that the press-in and discharge of the fluid may be repeated multiple times. In addition, although some press-fit fluid leaks from the slit, this leaked fluid also reduces frictional resistance with the soil.

<Effects of the Invention> As explained above, according to the method of the present invention, the frictional resistance between the buried pipe to be removed and the soil can be easily reduced, so that the pipe to be removed can be easily pulled out or pushed out. This has the effect of making it possible to conduct large diameter steel pipes and long-distance trenchless construction, which was previously considered impossible with trenchless methods.

[Brief explanation of the drawing]

1 to 4 are explanatory diagrams of one embodiment of the method of the present invention. 1... Slit, 2... Lid, 3... Fluid injection device, 5... Excavator.

Claims (1)

[Claims] 1 Form a vertical shaft at both ends of the buried and removed pipe, expose and cut both ends, form a slit in the axial direction of the buried and removed pipe, and then pressurize fluid into the removed pipe to expand the diameter, and then remove the fluid. A method for reducing frictional resistance of a buried and removed pipe, characterized by reducing the diameter by draining it.