JP2904004B2 - Piping method in soft ground - 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 embedding a water supply pipe or a drain pipe in a soft ground which is apt to cause land subsidence, such as a saturated clayey soil layer having low permeability and a landfill site of garbage. is there.

[0002]

2. Description of the Related Art As a countermeasure against land subsidence of pipes buried in the ground, pipes around a building are integrated with a pipe along the outer periphery of the building with an underground part of the building, and pipes not along the outer circumference are connected to an end of the building. Is generally fixed to a building, and a flexible (stretchable) joint is used as a joint with the outdoor piping to absorb the settlement amount of the ground with the joint. In general, a method of placing a pile on a soft ground to prevent land subsidence and placing the pile on the pile for piping in a general outdoor area is common.

[0003]

Even if an attempt is made to prevent land subsidence by driving a pile, the reaction force acting on the pile is not always uniform in the direction of the pipes. Will cause a breakage accident.
In addition, not only is it difficult to drive piles at the landfill site, but even if it can be driven, the long-term effect of preventing land subsidence is questioned. Therefore, there is a demand for a piping method that does not cause a breakage accident even if uneven settlement occurs in the ground.

[0004]

SUMMARY OF THE INVENTION According to the present invention, even if a slight uneven settlement of the ground occurs without taking special measures for preventing the settlement of the ground by driving a pile, the pipe itself follows the uneven settlement and the pipe is broken. It is an object of the present invention to provide a piping method that does not cause an accident.

That is, according to the present invention, a corrugated pipe is used as a sheath pipe, and a double pipe in which a flexible inner pipe longer than the sheath pipe is inserted is buried in the ground, and both ends of the sheath pipe are fixed to the side wall of the manhole. In addition, the present invention relates to a piping method in soft ground, characterized in that a surplus portion of an inner pipe is wound in a loop and stored in a manhole.

SUMMARY OF THE INVENTION The present invention is based on the rapid development of plastics technology in recent years. As a result, it is possible to obtain a pipe having sufficient tensile strength and compressive strength, being flexible, having excellent chemical resistance and durability. It is an invention made based on what has become.

In the present invention, two types of plastic tubes are used.

[0008] One type is a so-called corrugated pipe which is a sheath pipe for protecting the original pipe, and irregularities are continuously provided spirally along the circumferential direction of the pipe. A typical example of the material is a material mainly composed of hard polyethylene. Due to the corrugated shape, the compressive strength in the diameter direction is increased, the flexibility and the elongation in the longitudinal direction are enhanced, and the elongation in the longitudinal direction is about 30%. Furthermore, it also has a performance that can be sufficiently used in other strength and durability when buried in the ground.

Another type is an inner pipe which is an original pipe, which has chemical resistance, durability, various strengths, and flexibility enough to be wound in a loop. Representative examples of a material for producing such a flexible inner tube include those mainly composed of crosslinked polyethylene and those mainly composed of isotactic polybutene.

To combine these two types of plastic tubes into a double tube, it is only necessary to insert a flexible inner tube longer than the length of the sheath tube into the sheath tube. The sheath tube and the inner tube are selected so that the difference between the outer tube and the outer tube is not so large, the gap between them is not so large, and the tube can be easily inserted.

If the inner diameter of the inner pipe is larger than 50 mm, the range of choice of the pipe material may be narrowed, or the storage space and storage equipment for the surplus portion of the inner pipe may be increased, making construction difficult. In such a case, instead of one double pipe, a plurality of small-diameter double pipes are branched and connected in parallel.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 (a) is a partially cutaway side view showing an example of a double pipe used in the present invention, and FIG. 1 (b) shows an example in which the double pipe is buried in soft ground and piped. FIG. 1C is a longitudinal sectional view showing a state of the piping in a state where the soft ground has unequally settled after the piping in FIG. 1B.

As shown in FIG. 1 (a), the double pipe 6 is made of a material mainly composed of crosslinked polyethylene inside a sheath tube 1 which is a corrugated pipe mainly composed of a hard polyethylene. The flexible inner tube 2 is inserted, and the flexible inner tube 2 is considerably longer than the length of the sheath tube 1.

At the time of piping, both ends of the sheath tube 1 are fixed to the side walls of the manholes 3A and 3B, and both ends of the flexible inner tube 2 are connected to the valves 5 and 5, as shown in FIG. The surplus portion of the flexible inner tube 2 is taken up by the winder 4 (the winder 4 is upright at the center.
Frame with vertical bar and vertical through hole at center
Frustoconical winder main body,
The rod of the frame is inserted through the through hole. ) And lightly fixed, and housed in one manhole 3A. This double tube 6
Is buried in soft ground. It is preferable that the backfill soil at the time of burying the double pipe 6 is mainly made of sand, and the frictional resistance between the double pipe 6 and the ground is made as small as possible.

After the piping, if uneven settlement occurs in the soft ground,
Sheath pipe 1 as shown in FIG. 1 (c) with extension Then the
A tension is generated in the flexible inner tube 2 and the winding is performed by the tension.
The container body rotates around the rod inserted through the through hole
And, winder 4 wound flexible inner tube 2 of the surplus portion had the solving Ho Doka is being fed into the sheath tube 1, to absorb the forces due to uneven settlement. Therefore, even if uneven settlement occurs, the flexible inner tube 2
No abnormal stress is generated.

Manholes 3A and 3B for piping the double pipe 6
If it is considered that the extra length of the flexible inner pipe 2 that is sufficient for the expected amount of land subsidence cannot be accommodated in the manhole 3A, an additional manhole is provided in the middle, and This is achieved by dividing the tube 6 into a plurality of tubes in series.

FIG. 2 is a plan view showing an example in which only small-diameter double pipes are laid on soft ground on the site of a building,
(A) is an overall view, (b) is an enlarged view of part B of (a),
(C) is an enlarged view of a portion C of (a), (d) is an enlarged view of a D portion of (a), and (e) is an enlarged view of an E portion of (a).

The water supply pipe connected to the water supply main pipe 11 is not a single large-diameter pipe, but three parallel pipes 6 having an inner pipe inner diameter of 40 mm. Sewage drainage pumping pipe is not a single large-diameter pipe, but the inner pipe inner diameter is 40 mm
This is an example in which two double tubes 6 are used in parallel. To branch in parallel or to aggregate the branches, as usual,
The header 10 is used.

[0020]

【The invention's effect】

(1) Since a double tube is used, the inner tube is sufficiently protected both mechanically and chemically.

(2) Since the sheath tube is extendable and the inner tube is flexible and has a surplus portion, the sheath tube can follow uneven settlement, and an abnormal force is applied to the pipe due to uneven settlement. There is no.

(3) When two or more small-diameter double pipes branched in parallel are used instead of one large-diameter double pipe, complete water cutoff during replacement work is not necessary, and Can be supplied with water. Also, the construction becomes easy.

[Brief description of the drawings]

FIG. 1A is a partially cutaway side view showing an example of a double pipe used in the present invention, and FIG. 1B is a longitudinal section showing an example in which the double pipe is buried in soft ground and piped. FIG.
FIG. 4B is a longitudinal sectional view showing a state of the pipe in a state in which the soft ground has unequally settled after the pipe in FIG.

FIG. 2 is a plan view showing an example in which only a small-diameter double pipe is used for piping on soft ground in a building site, (a) is an overall view, and (b) is an enlarged view of a portion B in (a). FIG. 3C is an enlarged view of a portion C in FIG. 4A, FIG. 4D is an enlarged view of a portion D in FIG.
3 is an enlarged view of a portion E in FIG.

[Explanation of symbols]

1. sheath tube, 2. flexible inner tube, 3, 3A, 3B manhole, 4. winder, 5. valve, 6. double tube, 7. building 8. ..Watering faucets, 9 septic tanks, 10
··· Header, 11 ·· Main water supply mains.

Claims (2)

(57) [Claims] 1. A tube in which irregularities are continuously provided spirally along the circumferential direction (hereinafter referred to as a corrugated tube) as a sheath tube,
A double pipe with a flexible inner pipe longer than the sheath pipe is buried in the ground, the both ends of the sheath pipe are fixed to the side wall of the manhole, and the excess part of the inner pipe is wound in a loop and stored in the manhole. Piping method in soft ground characterized by performing. 2. The piping method in soft ground according to claim 1, wherein two or more small-diameter double pipes branched in parallel are used instead of one large-diameter double pipe.