JP2002295177A - Pipe for use in pipe jacking method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an earthquake resisting pipe for use in a pipe jacking method which carries out laying of fluid transporting pipes for waterworks, gas distribution, sewageworks, etc., without excavating the ground, wherein the pipe is buried in the ground while ensuring a sufficient expansion allowance functioning at the time of an earthquake, etc., suppressed in increase in propelling force, and relatively simple in structure. SOLUTION: The earthquake resisting pipe is for use in the pipe jacking method for burying the pipes in the ground in a manner being sequentially connected together. According to the earthquake resisting pipe, a peripheral portion of a cast iron pipe having an NS-type earthquake resisting joint is sheathed with a steel pipe, and concrete is placed between the cast iron pipe and the sheathing steel pipe, followed by providing an end face ring on a front end face of the sheathing steel pipe with respect to a propelling direction, in order to prevent twisting of the steel pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic pipe used in a propulsion method for laying a pipe for fluid transportation used for water supply, gas, sewerage and the like without cutting.

[0002]

2. Description of the Related Art Conventionally, as an embedding method for burying ductile cast iron pipes or the like, an open-cutting method in which the ground is cut and laid is generally used. However, in recent years, traffic volume has increased not only on main roads but also on general roads, and it has become difficult to cut off traffic due to excavation. For this reason, a propulsion construction method in which only the starting shaft and the reaching shaft are excavated, and the ductile cast iron pipe is sequentially propelled underground from the starting shaft to the reaching shaft and laid, has been widely adopted.

As a ductile cast iron pipe used in the above-mentioned propulsion method, there is a so-called T-joint for a propulsion method as shown in FIG. This T-shaped joint has a slot 10
1, socket 102, exterior concrete 103, rubber ring 10
6. It is composed of a stud bolt / nut 112, a flange 113, a rib 115, and the like. In addition, a general propulsion method uses a starting shaft 201 as shown in FIGS. 7 (a) and 7 (b).
In this method, a ductile cast iron pipe 204 for the propulsion method is press-fitted with a main push jack 203 and excavated by a leading conduit 205, and a conduit is laid without opening to the reaching shaft 202.

In this joint, one of the pipes has a receiving port 10.
2 is formed, and an insertion port 101 to be inserted into the receiving port is formed in the other tube. Exterior concrete 103 is formed on the outer peripheral portion of the pipe used for the propulsion method so as to be equal to the outer diameter of the receiving port 102, so as to reduce resistance during propulsion due to bulging of the receiving port. I have. The propulsive force of the pipe is transmitted to the end face 114 of the opening of the receiving port 102 via a rib 115 and a flange 113 provided at a position behind the insertion port 101.

In a configuration such as the T-joint for the propulsion method, when a certain or more pulling force acts during an earthquake, the stud bolt / nut 112 breaks and the receiving port 1
As long as the insertion port 101 does not come out from the pipe 02, the pipe moves in the axial direction to absorb the expansion and contraction, and the joint portion exhibits the ground followability with respect to the ground deformation at the time of an earthquake or the like. For this reason, there is no risk of impairing the water stopping performance.

[0006]

However, in the above-mentioned joint structure, when the amount of expansion and contraction expected at the time of designing the pipeline is exceeded due to an earthquake or the like, there is a possibility that the insertion port may come out of the receiving port. Further, the exterior concrete is provided so that the outer diameter of the entire pipe becomes substantially equal in order to prevent an increase in propulsion resistance due to the uneven shape of the joint portion, but the concrete is chipped or peeled during propulsion. The propulsion resistance sometimes increased. In order to solve this problem and reduce the frictional resistance as compared with the exterior concrete, the exterior of the exterior concrete is protected by a steel pipe (for example, Japanese Utility Model Application Laid-Open No. Hei 5-3398, Japanese Unexamined Patent Publication No. Hei 9-1450).
No. 8).

However, the steel pipe for protection described in Japanese Utility Model Laid-Open Publication No. Hei 5-3398 has a shape in which the tip is a tapered inclined surface and the end is bent at a right angle. There was a problem that it was difficult. Further, since the protection steel pipe is formed so that its bent end portion engages with a projection integrally provided on the outer peripheral surface of the insertion port, the projection provided at the insertion port (for example, the insertion port of the NS type pipe joint). Projection) cannot be mounted. On the other hand, in the case of Japanese Patent Application Laid-Open No. Hei 9-14508, since the front end of the steel pipe for protection is open, the peripheral edge of the opening may be turned up by the resistance of soil during propulsion. Further, neither of the above publications has an earthquake-resistant joint, and does not disclose application to, for example, NS pipes having excellent earthquake resistance. Therefore, the present invention
In the propulsion method of laying fluid transport pipes for water supply, gas, sewerage, etc. without cutting, seismic pipes with sufficient expansion and contraction can be buried at the time of an earthquake, etc. It is an object to provide a relatively simple propulsion method pipe having a structure capable of suppressing an increase in propulsion.

[0008]

In order to solve the above problems, the present invention employs the following configuration. That is, the propulsion method pipe according to the present invention is a seismic pipe used for a propulsion method for burying underground while connecting the pipes, and a steel pipe is provided on an outer peripheral portion of a cast iron pipe having an anti-seismic joint. Concrete is cast between the cast iron pipe and the exterior steel pipe, and an end face ring for preventing the steel pipe from being turned up is provided on an end face of the exterior steel pipe on the front side in the propulsion direction.

As the cast iron pipe, NS which is excellent in earthquake resistance is used.
It is preferable to use a cast iron pipe having a shaped joint (JWWA G 113/114 ductile cast iron pipe for water supply).
Since the NS-type cast iron pipe has a large bulge in the outer diameter direction in the outer diameter direction, it is particularly effective to eliminate irregularities on the outer peripheral portion of the concrete and the outer steel pipe. In addition, the end face ring includes a tubular portion fitted to the exterior steel pipe, and a plate-shaped portion covering the end face of the tubular portion. The plate-shaped portion is provided at an insertion opening of the NS-type cast iron pipe. It is preferable that a through hole having an inner diameter larger than the outer diameter of the insertion port projection is provided. A ring-shaped flange for transmitting thrust can be fixed to the outer surface of the end ring.

According to the present invention, a steel pipe for protection is provided on the outer periphery of a cast iron pipe having an earthquake-resistant joint, and concrete is filled between the steel pipe and the cast iron pipe. The outer peripheral portion of the propulsion pipe can be formed in a cylindrical shape without irregularities even if the propulsion pipe is provided. For this reason, an increase in propulsion can be suppressed. Further, since the end face ring is attached to the end opening of the steel pipe for protection, the protection steel pipe does not turn up during propulsion.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described more specifically based on embodiments of the present invention shown in the drawings.

FIG. 1 shows the structure of a pipe for a propulsion method according to the present invention. A joint J of this cast iron pipe P is an NS type joint usually used as a seismic joint for water supply. And receptacle 2. A ring-shaped projection 3 is integrally provided on the outer peripheral surface of the distal end portion of the insertion port 1.

The inner peripheral surface 2a of the receiving port 2 is provided with a rubber ring groove 4a for accommodating a rubber ring 4 for sealing and a lock ring groove 5a. A rubber ring 4 for sealing is fitted into the rubber ring groove 4a, and a lock ring 5 formed as a single annular body is inserted into the lock ring groove 5a via a lock ring centering rubber 6. When the lock ring 5 is fitted and an excessive pulling force due to an earthquake or the like is applied, the lock ring 5 and the insertion port projection 3 are engaged with each other, so that the insertion port 1 is prevented from deviating.

As shown in FIG. 2B, ribs 12,... Are fixed at appropriate intervals (in the illustrated example, a total of eight at 45 ° intervals) on the outer peripheral portion of the insertion port 1 on the rear side. I have. As shown in FIG. 3, the rib 12 has an upper surface formed as an inclined surface 12a such that the rear in the propulsion direction is lower, and a lower protruding portion 13 that protrudes forward along the outer peripheral surface of the cast iron tube is integrally formed on the front side. It is formed in. The ribs 12 may be fixed by a fixing method that does not cause slippage during propulsion, such as welding, an adhesive, a metal band, or a bolt.

An outer concrete 20 is provided on the outer periphery of the cast iron pipe.
Further, an outer spiral steel pipe 30 which is a protection steel pipe is provided on an outer peripheral portion thereof. The exterior concrete 20 is also provided on an outer peripheral portion of a flange portion (maximum diameter portion) of the NS type joint, and an outer peripheral surface thereof has a cylindrical shape with an equal diameter. The exterior concrete 20 is cast to the front end of the rib 12. The outer spiral steel pipe 30 serving as the protective steel pipe is a steel pipe formed by spirally winding a steel plate having a thickness of several mm, and the end of the socket 2 of the cast iron pipe is formed so as to cover the outer peripheral surface of the outer concrete 20. It is fitted from the portion to the front end of the rib 12 provided at the base of the insertion port 1 on the opposite side. In the illustrated example,
Exterior concrete 20 is cast to the outer periphery of the receiving port 2,
Although the outer diameter of the pipe as a whole is large, in some cases, the outer surface of the portion (flange portion) of the maximum diameter of the receiving port 2 is exposed, and the outer peripheral surface is flush with the outer peripheral surface of the protective steel pipe 30. You may make it become. The exterior concrete only needs to have a compressive strength such that the thrust does not suddenly increase due to peeling or the like.

A cap-shaped end ring 40 is attached to the insertion port side of the protective steel pipe 30, that is, the front end in the propulsion direction, and a ring-shaped flange 45 is fixed to the front side. The flange 45 is for transmitting a propulsion force to a propulsion force transmission member (collar) 60 described below.
Both front and rear surfaces are formed as flat steel rings. As shown in FIG. 4, the end face ring 40 includes a tubular portion 41 fitted externally to the protective steel pipe 30 and a plate-shaped portion 42 covering an end surface of the tubular portion, and a central portion of the plate-shaped portion. Is provided with a through hole 43 whose inner diameter is slightly larger than the outer diameter of the ring-shaped insertion projection 3 provided at the tip of the insertion opening 1.

This propulsion method pipe is manufactured as follows. First, as shown in FIG. 5A, a rib 12 is fixed to an appropriate position on the outer surface of the insertion port 1 of the cast iron pipe P by a method such as welding.
Next, as shown in FIG. 2B, the protective steel pipe 30 is fitted to the outside and the cast iron pipe is centered. This centering can be easily performed by using the plurality of ribs 12,... Or applying a wooden or rubber centering member between the protective steel pipe 30 and the cast iron pipe.

A cast iron pipe having a protective steel pipe 30 as an exterior is inserted, and the opening 1 is raised with the opening 1 facing upward. An appropriate plate such as a steel plate is laid under the receiving opening 2. In this state, concrete is poured into the gap between the cast iron pipe and the protective steel pipe as shown in FIG. In this case, the protection steel pipe 30 can be used as a concrete casting formwork. After the concrete is cast, the end face ring 40 is attached as shown in FIG. At this time, since the inner diameter of the end face ring is larger than the insertion projection 3, the end ring can be easily fitted by being fitted from the tip of the insertion opening 2. The end ring 40 does not need to be fixed to the protective steel pipe by welding or the like, and the cylindrical portion 41 may be fitted into the mouth of the protective steel pipe 30. After a while
As shown in FIG. 5D, a ring-shaped flange 45 is fitted and fixed to the rib 12 by welding. Thereby, the end face ring 40, the ribs 12, and the flange 45 are fixed.

This propulsion method pipe is, as shown in FIG.
The propulsion force transmitting member (collar) 60 is interposed between the flange 45 and the end surface 2b of the socket 2 and joined. The propulsion force transmitting member 60 has a predetermined compressive strength during propulsion and transmits the propulsion force to the front pipe, and is crushed after completion of the propulsion work, whereby the expansion and contraction performance of the seismic pipe can be secured. is there.

The propulsion force transmitting member 60 is formed as an annular one-piece object, and is made of a material having appropriate brittleness and rigidity, such as concrete and ceramics. The thrust transmitting member 60 is made of concrete containing a static crushing agent as an admixture. The static crushing agent is capable of crushing the propulsion force transmitting member 60 after completion of the propulsion. This static crushing agent includes a lime-based material mainly composed of calcium oxide (CaO),
aO.3Al ₂ O ₃ .CaSO ₄ , CaSO ₄ and C
There are two types of calcium-sulfo-aluminate (CSA) based on aO. Lime-based CaO undergoes a hydration reaction to produce fine colloidal calcium hydroxide Ca (OH) ₂ . This Ca (OH) ₂
Grows into a large anisotropic hexagonal plate-like crystal over time, and the crystal pressure generated by the hydration reaction in a constrained state causes the crystal pressure to push each other. As a result, an inflation pressure is generated on the constraining wall. Also, in the case of the CSA type, since it grows into needle-like crystals called ettringite by a general hydration reaction formula as shown below, an expansion pressure to the constraining wall is generated similarly to the lime type. I do.

[0021]

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When these inflation pressures exceed the tensile strength of the thrust transmitting member, cracks are generated, and the propagation of the cracks is caused by the continued expansion of the static crushing agent. For this reason, a large number of cracks are formed in both the circumferential direction and the axial direction of the thrust transmitting member,
Crushing takes place. As described above, since the two main components have the effect of crushing the propulsion force transmitting member in both the lime-based and CSA-based components, either component may be used. Further, components other than these two types may be used as long as the object of the present invention is achieved. In the case of the direct pushing propulsion method, when the compressive stress of the propulsion force transmission member becomes zero, when a large force in the pushing direction acts due to an earthquake or the like, the fragments are discharged into the soil, and the joint shrinks. Becomes possible.

The static crushing agent is a component similar to the swelling agent generally used for expanded concrete, and promotes crushing of concrete or the like by containing the swelling agent in excess. In addition, this static crushing agent is generally used for crushing rocks and concrete accompanying construction work, and can crush concrete and the like without generating vibration, noise, stepping stones, etc. Moreover, since it does not contain harmful components, no adverse effect on the tubular body is expected. In addition, besides mixing the static crushing agent as a concrete admixture as described above, a perforated portion is appropriately provided in the axial direction of the propulsion force transmitting member, and the static crushing agent is inserted into the perforated portion, and the propulsion is performed. A method of crushing the force transmitting member is also conceivable. The propulsion force transmitting member is set so as to expand and crush after the propulsion is completed. As a result, the thrust transmitting member is cracked and crushed due to the expansion of the crushing agent, so that the compressive strength of the thrust transmitting member becomes almost zero, and the contraction amount of the joint is secured by the front and rear width of the thrust transmitting member. Is done.

The propulsion method using the above-mentioned propulsion method pipe will be described below. First, the insertion port 1 of the succeeding pipe is inserted into the receiving port 2 of the preceding pipe and spliced, and the pipes are sequentially inserted while excavating underground with the first excavator.
At this time, the exterior concrete is cast on the outer periphery of the pipe and the outer diameter is made uniform, so that the propulsion resistance is small.
Since the outer surface of the exterior concrete is protected by the protective steel pipe 30, the concrete does not peel or chip during propulsion. Also, since the end face ring 40 is attached to the front end of the protective steel pipe in the propulsion direction,
There is no possibility that the edge of the protective steel pipe is turned up.

The propulsion force during the propulsion is transmitted from the insertion port 1 of the pipe to the receiving port 2 of the preceding pipe via the rib 12, the flange 45, and the member 60 for transmitting the propulsion force. Therefore, distance L ₁ between the inner end face 2c of the insert port 1 of the tip and socket 2 is maintained, inserted port projection 3 and the distance between the lock ring 5 L ₂
The propulsion is performed in a state where is maintained.

When an earthquake occurs after the installation and a strong pushing force acts on the pipe joint, the insertion port 1 is pushed in until it hits the rear end face 2c of the receiving port 2. That is, the pipe joint is that there is only shrinkage allowance L ₁ in FIG. 1. Also, when a pull-out force acts on the pipe joint due to an earthquake or the like,
The insertion projection 3 is pulled out until it engages with the lock ring 5 (distance L ₂ ), and the engagement of the two prevents the insertion opening from being detached. For this reason, as stipulated in the National Land Development Technology Center “Technical Standards for Seismic Joints for Underground Pipes and Pipes” (draft), it is possible to provide withdrawal allowance of 1% or more of the pipe length, The pushing allowance can be set to 1% or more of the pipe length.

[0027]

As is clear from the above description, the pipe for a propulsion method of the present invention is capable of suppressing an increase in propulsion force by eliminating irregularities on the outer peripheral portion of a pipe having an earthquake-resistant joint made of telescopic material. it can. In the NS-type pipe provided with the NS-type joint having particularly excellent earthquake resistance, the outer peripheral portion of the receiving port is largely bulged, but the propulsion resistance can be reduced by the present invention. Moreover, since the outer peripheral surface of the exterior concrete for eliminating irregularities is covered with the protective steel pipe, the concrete does not peel or chip during propulsion. Moreover,
The friction resistance with the soil is lower than the exterior concrete, and the propulsion can be reduced. Furthermore, the front end of the protective steel pipe that protects the exterior concrete is particularly easily turned during propulsion, but since the end face ring is attached to this part, the steel pipe is hard to be turned, and a good propulsion state can be maintained. it can.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a joint portion of a pipe for a propulsion method according to the present invention.

FIGS. 2A and 2B are a longitudinal sectional view and a view on arrow A of a pipe for a propulsion method, respectively.

FIG. 3 is an enlarged view of the main part.

4A and 4B are a cross-sectional view and a front view of an end face ring.

FIG. 5 is an explanatory view of a manufacturing method.

FIG. 6 is a sectional view of a main part of a conventional pipe for a propulsion method.

FIG. 7 is a cross-sectional view illustrating a state during propulsion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insertion opening 2 Reception opening 3 Insertion protrusion 5 Lock ring 12 Rib 20 Exterior concrete 30 Protective steel pipe 40 End face ring 60 Propulsion force transmission member

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Naoki Tomita 1-12-19 Kitahorie, Nishi-ku, Osaka-shi, Osaka F-term in Kurimoto Iron Works Co., Ltd. (Reference) 2D054 AC18 AD27

Claims (4)

[Claims] Claims: 1. An earthquake-resistant pipe used in a propulsion method for burying underground while connecting pipes, wherein a steel pipe is provided on the outer periphery of a cast iron pipe having an earthquake-resistant joint, and A pipe for a propulsion method, wherein concrete is poured between the pipes, and an end face ring for preventing the steel pipe from being turned is provided on an end face of the exterior steel pipe on the front side in the propulsion direction. 2. The propulsion method pipe according to claim 1, wherein an NS-type cast iron pipe having an earthquake-resistant NS-type joint is used as the cast iron pipe. 3. An end face ring includes a tubular portion externally fitted to an exterior steel pipe, and a plate-like portion covering an end face of the tubular portion, wherein the plate-like portion has a diameter larger than an outer diameter of an insertion opening of the cast iron pipe. The propulsion method pipe according to claim 1, wherein a through hole having a large inner diameter is provided. 4. The propulsion method pipe according to claim 1, wherein a ring-shaped flange is fixed to an outer surface of the end face ring.