JPH1068290A - Method of embedding gas pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reasonably embed a gas pipe through which fuel gas having a pressure of about 1 to 10kg/cm<2> flows. SOLUTION: A gas pipe A is formed in such a way that an inner pipe 2 such as a steel pipe is fitted in an outer pipe such as a vinyl chloride pipe, a polyethylene pipe, a synthetic resin pipe or a steel pipe, and holding members are interposed between the outer and inner pipes so as to define a gap therebetween. The gap pipe A is caused to follow an excavator for excavating the natural ground or a guide machine B for compacting the natural ground so as to form a tunnel, and a base pusher C laid in a vertical shaft D applies a thrust force to the inner pipe 2 so as to advance the inner pipe 2 from the vertical shaft D to a destination vertical shaft E. Each time when a single gas pipe A is advanced, a new inner pipe 2 is welded and connected to the inner pipe 2 in thus advanced gas pipe A, and accordingly, the outer pipes 1 are made to abut against each other so as to repeat the advance of the outer pipes 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas pipe burying method for burying a gas pipe through which fuel gas flows in the ground.

[0002]

2. Description of the Related Art Various pipelines, such as sewer pipelines, water pipelines, electric wire pipelines and gas pipelines, are buried underground. Among them, a gas pipe through which a fuel gas typified by natural gas flows has a very special structure as compared with other pipes because the flowing gas must not leak. In other words, the gas pipe buried underground is constructed as a double pipe in which an inner pipe made of steel pipe is fitted to an outer pipe made of fume pipe or steel pipe. Buried underground.

The present applicant has already applied for a patent by developing a technique of laying a gas pipe by propelling a double pipe composed of steel pipes for both the inner pipe and the outer pipe (Japanese Patent Application No. 5-65948). No. etc.). In this technology, a pipe is inserted into a gap formed between an inner pipe and an outer pipe, and a double pipe is propelled while supplying a lubricant circulated in the pipe between the outer pipe and the ground. Is what you do. Then, every time one double pipe is propelled, a new double pipe is welded to the double pipe, and this double pipe is propelled again,
A gas pipeline will be laid underground.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is to lay a high-pressure gas pipeline in which the pressure of flowing gas is set to 10 kg / cm ² or more. However, there is one in the gas pipe, called intermediate pressure gas line pressure of the gas is set to 1kg / cm ² ~10kg / cm ² for distribution, the method to rationally laying the good gas line Development is required.

An object of the present invention is to provide a method of burying a gas pipe through which medium-pressure gas flows rationally underground.

[0006]

In order to solve the above problems, a gas pipe burying method according to the present invention embeds a gas pipe in which an inner pipe made of a steel pipe is fitted to an outer pipe made of a synthetic resin pipe or a steel pipe. A method of applying a thrust to the inner pipe of the gas pipe to propel the inner pipe and the outer pipe from the starting pit toward the arrival pit, and then adding new gas to the inner pipe of the already propelled gas pipe. The inner pipe of the pipe is welded to make it continuous, and the outer pipe of the already propelled gas pipe is brought into contact with the outer pipe of the new gas pipe to make it continuous, and further, the thrust is given to the inner pipe of the new gas pipe It is characterized by promoting.

In the above gas pipe burying method, a thrust is applied to the inner pipe when burying a double pipe gas pipe formed by fitting an inner pipe made of a steel pipe to an outer pipe made of a synthetic resin pipe or a steel pipe. By doing so, the inner pipe and the outer pipe can be propelled from the start shaft to the arrival shaft. After propelling one gas pipe, the inner pipe of the new gas pipe is connected to the inner pipe of the already propelled gas pipe by welding, and the outer pipe of the new gas pipe is connected to the already propelled gas pipe. By contacting and connecting to the outer pipe and applying thrust to the inner pipe of this new gas pipe,
It can promote already-propelled and new gas pipes. Therefore, by continuously performing this operation, a gas pipe having an inner pipe welded and connected between the start shaft and the arrival shaft can be buried.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the gas pipe burying method will be described below with reference to the drawings. FIG. 1 is a view for explaining a process of burying a gas pipe, FIG. 2 is a view showing a main part of a gas pipe to be propelled, and FIG. FIG.

In the gas pipe burying method according to the present invention, a plurality of gas pipes A are made to follow a leading conductor B and are provided with a thrust by a main pushing device C so as to be propelled from a start shaft D to an arrival shaft E, When the leading conductor B reaches the arrival shaft E, a plurality of gas pipes A connected between the shafts D and E are buried in the ground to lay a pipeline. In particular, in the gas pipe through which the medium-pressure gas flows, the internal pressure acting on the inner pipe 2 constituting the gas pipe A becomes lower, and the pipe 2 can counteract the earth pressure. However, since welding means is required as a means for connecting the inner pipe 2, the outer pipe 1 made of a corrosion-resistant material is disposed for the purpose of protecting the welded portion and the outer peripheral surface of the inner pipe 2. Is preferred.

The gas pipe A is formed as a double pipe in which an inner pipe 2 made of a steel pipe is fitted to an outer pipe 1 made of a synthetic resin pipe such as vinyl chloride or polyethylene or a steel pipe. An appropriate gap is formed between the tubes 2. In this gap, a holding member 3 such as an O-ring is arranged to hold the gap dimension. That is, in the gas pipe A, the outer pipe 1 and the inner pipe 2 are fitted so as to be slidable in the axial direction and rotatable in the circumferential direction while maintaining a gap between the holding members 3.

The outer tube 1 mainly has a function of protecting the corrosion-resistant film formed on the surface of the inner tube 2, further prevents the corrosion-resistant film from being turned up by friction with earth and sand during propulsion, and additionally assists in the inner tube. It has a function of reinforcing the pipe 2. The difference between the inner diameter of the outer tube 1 and the outer diameter of the inner tube 2, that is, the size of the gap formed between the outer tube 1 and the inner tube 2 is not particularly limited.

The inner pipe 2 has a predetermined thickness corresponding to the pressure of the gas flowing inside. When a new gas pipe A is connected to the already propelled gas pipe A, the inner pipe 2
Ends are butt-welded. For this reason, a groove corresponding to the wall thickness is formed at the end of the inner tube 2. Further, a corrosion-resistant coating is applied to the surface of the inner tube 2.

The holding member 3 holds the gap between the outer tube 1 and the inner tube 2 to maintain the concentricity of the two, and any member having this function can be used. In particular, it is preferable that the holding member 3 can easily allow the outer tube 1 to slide in the axial direction and to rotate in the circumferential direction.

In the gas pipe A constructed as described above, when buried in the ground, the outer pipe 1 prevents the inner pipe 2 through which gas flows from directly acting on the inner pipe 2 to prevent the soil and groundwater from directly acting. It is possible to protect the outer peripheral surface and the welding site.

The leading conductor B forms a tunnel for propelling the gas pipe A in the ground. Depending on conditions such as the outer diameter of the outer pipe 1 constituting the gas pipe A and the properties of the ground, For example, an excavator that drives a cutter head attached to the tip to excavate the ground and discharges the excavated earth and sand to the ground to form a tunnel, or a consolidation head attached to the tip to consolidate the soil of the ground and tunnel. Is used selectively. In the present embodiment, the conductor B
A non-drilling tip conductor is used.

The main pushing device C is installed in the starting shaft D,
It has a function of applying a thrust to the leading conductor B and the gas pipe A following the leading conductor B to propel it toward the arrival shaft E.

The main pushing device C is provided with a leading conductor B or a gas pipe A.
Rails 4a for guiding the initial propulsion direction while placing
A frame 4 having a supporting wall 4b formed integrally with the rail 4a and abutting against a side wall of the starting shaft D to support a reaction force during propulsion; and a jack 5 having one end attached to the supporting wall 4b. A push wheel 6 attached to the jack 5 and driven by the jack 5 to reciprocate along the rail 4a;
It is constituted by.

The starting shaft D and the arriving shaft E are each configured to have a predetermined depth and a planar shape at a preset position on a predetermined laying line of a target gas pipeline.

Next, a procedure for laying a gas pipeline having a plurality of gas pipes A buried between the start shaft D and the arrival shaft E will be described. Prior to the propulsion of the gas pipe A, the leading conductor B is propelled. That is, the leading conductor B is placed on the rail 4a of the main pushing device C, and the pushing wheel 6 is brought into contact with the rear end of the leading conductor B to drive the jack 5 to apply thrust to the leading conductor B. , The tip conductor B can be propelled toward the arrival shaft E. In the course of propulsion of the leading conductor B, the tunnel can be formed without the compacting head compacting the ground and excavating earth and sand.

After propelling the leading conductor B, the gas pipe A positioned at the head is placed on the rail 4a, and the gas pipe A (the outer pipe 1,
The front end of the inner tube 2) is brought into contact with the rear end of the front conductor B. In the gas pipe A positioned at the head, the length of the outer pipe 1 is shorter than the length of the inner pipe 2 so that the work of welding a new gas pipe A to the gas pipe A can be easily performed. Is preferred. When propelling the gas pipe A, the auxiliary pipe 7 corresponding to the difference in the length of the outer pipe 1 and the inner pipe 2 is temporarily connected to the outer pipe 1 so that the outer pipe 1, the inner pipe 2 It is possible to apply thrust to the vehicle.

When the leading conductor B and the gas pipe A following the leading conductor B are propelled, the thrust of the main pushing device C is transmitted to the leading conductor B via the inner pipe 2 made of a steel pipe, and at the same time, the auxiliary pipe 7 is moved. Is transmitted to the outer tube 1 via Therefore, it is possible to propel the leading conductor B and the gas pipe A. Propelled gas pipe A
In the case, the outer peripheral surface of the outer pipe 1 comes into contact with the ground and the earth pressure acts, and the inner pipe 2 is held concentric with the outer pipe 1 by the holding member 3.

The gas pipe A is propelled by the main pushing device C,
With the rear end of the pipe A protruding from the starting shaft D, the pushing wheel 6 is pulled back to the bearing wall 4b. Then, the auxiliary pipe 7 is removed from the already propelled gas pipe A, and a new gas pipe A is mounted on the rail 4a.

By removing the auxiliary pipe 7 from the gas pipe A that has already been propelled, the rear end side of the inner pipe 2 is exposed, and the inner pipe 2 of the new gas pipe A mounted on the rail 4a is connected to the outer pipe 1. On the other hand, the inner pipe 2 is slid in the axial direction to expose the front end of the inner pipe 2 and face the inner pipe 2 of the gas pipe A which has already been propelled. In this state, the inner pipe 2 of the gas pipe A already propelled and the inner pipe 2 of the new gas pipe A are butt-welded. At this time, the inner tube 2 is replaced with the outer tube 1
The axis is held by the holding member 3 on the basis of, and are concentric with each other.

After welding the inner pipe 2, the outer pipe 1 of the new gas pipe A is advanced to make contact with the outer pipe 1 of the gas pipe A which has already been propelled, and the auxiliary pipe 7 is attached. Gas pipe A in the ground
When ground is embedded, groundwater must not enter the gap between the outer pipe 1 and the inner pipe 2 from the contact surfaces of the outer pipes 1, so that an adhesive is applied to the contact surfaces and bonded. It is preferable that the gasket packing is attached to the contact surface so that the gasket can be sealed.

Next, the push ring 6 is brought into contact with the inner pipe 2 and the auxiliary pipe 7 of the new gas pipe A mounted on the rail 4a and propelled. By repeating this operation, the leading conductor B and the gas pipe A are propelled toward the arrival shaft E, and the leading conductor B is moved to the arrival shaft E.
Is reached, the leading conductor B is removed from the arrival shaft E, so that a plurality of gas pipes A are provided between the start shaft D and the arrival shaft E.
Can be buried, and a gas pipeline can be formed by the buried gas pipe A.

In the gas pipe A buried underground, the earth pressure of the ground acts on the outer pipe 1, so that the outer pipe 1 may be deformed. However, the outer tube 1 only needs to be able to protect the rust-preventive coating film of the inner tube 2, and even if the outer tube 1 is deformed and comes into close contact with the inner tube 2, the above-mentioned protection function is not impaired. When the outer pipe 1 comes in close contact with the inner pipe 2, the inner pipe 2
Can be countered by:

[0027]

As described in detail above, in the gas pipe burying method according to the present invention, a gas pipe formed by fitting an inner pipe made of a steel pipe to an outer pipe made of a synthetic resin pipe or a steel pipe is used as the inner pipe. By applying thrust and propelling from the starting shaft to the arrival shaft, it can be buried between both shafts.

In the buried gas pipe, an outer pipe made of synthetic resin or steel is arranged on the outer circumference of the inner pipe through which gas flows. For this reason, it is possible to prevent earth and sand from adhering to the inner pipe and contact with groundwater, thereby preventing corrosion of the inner pipe, protection of the corrosion-resistant coating, and prevention of turning during propulsion. It has the feature of.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a process of burying a gas pipe.

FIG. 2 is a diagram showing a main part of a gas pipe to be propelled.

FIG. 3 is a diagram illustrating a state in which a new gas pipe is connected to a gas pipe that has already been propelled.

[Explanation of symbols]

 Reference Signs List A gas pipe B tip conductor C main pushing device D starting shaft E arrival shaft 1 outer tube 2 inner tube 3 holding member 4 frame 5 jack 6 push ring 7 auxiliary tube

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Takashi Ogawara 1-14-14 Honkita, Ichikawa City, Chiba Prefecture (72) Inventor Hideki Uno 1118-22, Wakamatsucho, Tokorozawa City, Saitama Prefecture (72) Inventor Tohru Sato Kanagawa 127-1-110 Shimosakunobu, Takatsu-ku, Kawasaki-shi (72) Inventor Yutaka Shindo 4-34-12-104 Sengoku, Bunkyo-ku, Tokyo

Claims (1)

[Claims] 1. A method of burying a gas pipe in which an inner pipe made of a steel pipe is fitted to an outer pipe made of a synthetic resin pipe or a steel pipe, wherein a thrust is applied to the inner pipe of the gas pipe to form the inner pipe and The outer pipe is propelled from the starting shaft to the arrival shaft, and then the inner pipe of the already propelled gas pipe is welded to the inner pipe of the new gas pipe to be continuous, and the outer pipe of the already propelled gas pipe is connected to the outer pipe of the already propelled gas pipe. A gas pipe burying method characterized in that an outer pipe of a new gas pipe is brought into contact with the pipe to make the pipe continuous, and furthermore, a thrust is applied to the inner pipe of the new gas pipe for propulsion.