JP2000017987A - Propulsion method and pipe fitting for use therein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-open-cut propulsion method, for burying a fluid transporting pipeline for use with city water, gas, sewage, or the like, and a seismic propulsion pipe fitting suited for use therein. SOLUTION: This pipe fitting 1 is an NS-type fitting normally used as a seismic fitting of city water and comprises a spigot 2 and a socket 3. The spigot 2 has a spigot projection 5 provided integrally with the outer peripheral surface of the end of a ductile pipe 4. In the event that a large drawing force works on the pipe fitting in an earthquake or the like, the spigot projection 5 locks to a lock ring 17 to prevent the spigot 2 from being drawn out of the socket 3. The spigot projection 5 is provided in the form of a ring on the entire outer peripheral part of the spigot 2. A flange 7 is integrally provided in a position near the rear of the spigot 2. Reinforcing ribs for backup are provided on the back part of the flange 7 at appropriate intervals to one another. The flange 7 and the reinforcing ribs 8 are metallic and fixed on the outer peripheral surface of the spigot 2 by welding or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-cutting propulsion method for burying a pipe for fluid transportation used for water supply, gas, sewerage, etc. underground, and a seismic propulsion pipe joint suitable for use in the method. .

[0002]

2. Description of the Related Art There is a pipe-in-pipe method as one method of embedding a fluid transport pipe such as a ductile cast iron pipe. This method is a method of inserting a new pipe into an existing old pipe, and is widely used because it does not require digging.

[0003] A pipe joint in a conventionally adopted pipe-in-pipe method is, for example, as shown in FIG. This joint 100 is called a PII type joint.
It comprises a receiving port 101, an insertion port 102, a lock ring 103, a set bolt 104, a rubber ring 105 and the like.

FIG. 9 shows an outline of the above conventional pipe-in-pipe method, in which a new pipe P having a smaller diameter is installed in an existing pipe P ′ buried between a start pit S and a destination pit R. Insert A hydraulic jack J is installed in the starting pit. The rear part of the hydraulic jack abuts against the reaction force receiver H, and the front part presses the new pipe P via the push angle B.
The new pipes P are sequentially joined by inserting the insertion port 102 at the front end thereof into the receptacle 101 at the rear end of the preceding new pipe, and are pushed into the existing pipe. A leading sled K is attached to the tip of the new tube at the head.

The joining of the new pipes P,... Is performed as follows. First, the lock ring 103 and the rubber ring 105
To the inside of the socket. Thereafter, the hydraulic jack J is operated, the insertion port 102 is inserted into the receiving port 101, and the set bolt is tightened. Thereby, the succeeding new pipe is joined to the rear part of the preceding new pipe whose rear end faces the starting pit. When the subsequent new pipe is joined, press with hydraulic jack J,
A series of joined rows of pipes are advanced toward the destination shaft.
The driving force of the hydraulic jack is determined by the lock ring 103,
It is transmitted by the contact with the end face of the lock ring groove 107. In the figure, a new pipe is inserted into the existing pipe. However, a method of inserting a new pipe into the pipe by the pipe-in-pipe method is also performed in the same manner.

Next, FIG. 10 shows a propulsion method using a UF type ductile pipe slightly different from the above. The UF type ductile pipe for the propulsion method includes a receiving port 201 and an insertion port 20.
2. It is composed of rubber ring 205, lock ring 203, set bolt 204, push ring 208, bolt 209, connecting rod 210, exterior concrete 211, and the like. When joining the UF type ductile pipe, first, lock ring 203
Is mounted in the lock ring groove 207 on the inner surface of the receptacle in an enlarged state. Next, after inserting the insertion hole into the receiving port by the propulsion jack, the set bolt 204 is tightened, and the lock ring 203 is attached to the lock ring groove 207. Then, from the inner surface side, the rubber ring 205, the pressing ring 208, the connecting rod 2
10 is fastened with bolts 209. Finally, mortar is filled into the bolt portion on the inner surface of the receiving port.

The UF type ductile pipe is pressed into the starting tunnel S by the propulsion jack J from the starting pit S as described above, or is propelled to the destination pit R while excavating by the leading conduit. The driving force at this time is transmitted through the engagement between the lock ring 203 and the lock ring groove 207.

[0008]

In the case of the PII type ductile pipe for the pipe-in-pipe method described above, after the pipe-in is completed, the lock ring 103 and the end face of the lock ring groove 107 are in contact with each other as shown in FIG. Therefore, the insertion port 102 cannot move in a direction to enter the reception port 101. For this reason, there is a problem that the joint does not satisfy the performance as an earthquake-resistant tube that needs to expand and contract in both directions.
When a large pull-out force acts on the joint due to an earthquake or the like, the lock ring 103 and the lock ring groove 107
By engaging with, exerts a departure prevention force,
S-type ductile pipes commonly used as seismic joints,
It can withstand half the pulling force of SII type ductile tubes as well as NS type ductile tubes.

In the case of the UF type ductile tube,
When the propulsion is completed, the lock ring 203 is in the lock ring groove 207. When an earthquake or the like occurs in this state and a pushing force or a pulling force acts on the joint, the joint part functions as a detachment prevention joint that is rigidly connected, and thus does not have a joint expansion / contraction amount necessary for the earthquake-resistant joint. Furthermore, since the joint is joined from the inner surface of the pipe, there is a problem that only a pipe having a nominal diameter of 700 mm or more, which is put into the pipe by an operator, can be joined. In addition, UF
The applicable diameter of the ductile tube is Φ700 to 2600 mm.

As described above, none of the conventional ductile pipes for a propulsion method has the necessary amount of expansion and contraction as an earthquake-resistant joint, and therefore, there is a high possibility that the joint will be damaged by the occurrence of an earthquake. Therefore, an object of the present invention is to bury a pipe in a state having a sufficient amount of expansion and contraction as a seismic joint.

[0011]

In order to solve the above problems, the present invention employs the following configuration. That is, the propulsion method according to the present invention is a propulsion method for burying underground while connecting pipes, and is capable of transmitting propulsive force between an insertion port and a receiving port of the pipe, and is more than the propulsive force. When a large pressing force is applied, a thrust transmitting member capable of contracting in the pipe axis direction is interposed, and the thrust is transmitted to the preceding pipe through the thrust transmitting member.

Further, according to the pipe joint according to the present invention, in a pipe joint for connecting a pipe by fitting an insertion port and a reception port, a gap between the inner peripheral surface of the reception port and the outer peripheral surface of the insertion port is sealed. And a lock ring and an insertion projection which engages with the lock ring to prevent deviation of the insertion port, and a flange provided on an outer peripheral portion of the insertion port and a reception port. A thrust transmitting member capable of transmitting a propulsion force and contracting by a pressing force greater than the propulsion force is interposed between the end portion.

The thrust transmitting member is capable of transmitting a thrust to a preceding pipe during construction of the propulsion method, and contracts when it receives a pressing force greater than the thrust after the end of propulsion. Is adopted so as to be shortened. Such a material includes, for example, a porous block made of metal, resin, or the like. More specifically, for example, a block of low-expansion polystyrene can be preferably used. In addition, as a shape of this thrust transmitting material, it is sufficient that the thrust can be transmitted uniformly to the entire circumference of the pipe,
A ring-shaped member fitted to the outer peripheral portion of the insertion port is preferable.

According to the present invention, the propulsion force can be transmitted to the preceding pipe through the thrust transmitting member during the propulsion work, so that the pipe can be effectively propelled. Further, when a pressing force greater than the propulsion force is applied after the propulsion is completed, the thrust transmitting member contracts in the pipe axis direction, so that there is a margin for expansion and contraction at the fitting portion between the insertion port and the receiving port, It has a function as an earthquake-resistant joint.

[0015]

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 is a sectional view showing the structure of a pipe joint according to the present invention. This pipe joint 1 is an NS type joint usually used as a seismic joint for water supply. Mouth 3 The insertion port 2 has an insertion port projection 5 integrally provided on the outer peripheral surface of the distal end portion of the ductile tube 4. When a large pull-out force acts on the pipe joint due to an earthquake or the like, the insertion port projection 5 and a lock ring 17 described later engage with each other to prevent the insertion port from coming out of the receiving port. The insertion port projection 5 is provided in a ring shape over the entire outer peripheral portion of the insertion port 2. A flange 7 is integrally provided at a position on the rear side of the insertion port 2. Reference numerals 8, ... denote reinforcing ribs for backup provided at appropriate intervals on the back surface of the flange 7. These flange 7 and reinforcing rib 8
Is made of metal and fixed on the outer peripheral surface of the insertion port 2 by welding or the like.

The receiving port 3 is formed by enlarging the rear portion of the ductile tube 4 in a substantially funnel shape, and has a groove 1 for mounting a rubber ring on the inner surface thereof.
0 and a lock ring groove 12 are provided. An inward flange 13 is formed at the rear end of the socket 3, and the end face thereof is formed as a plane 13 a perpendicular to the axial direction. A rubber ring 15 for sealing is fitted in the groove 10, and a lock ring 17, which is expanded and singly formed in the lock ring groove 12, is inserted through a rubber ring 18 for centering the lock ring. It is fitted. 19 is an interior material and 20 is an exterior concrete.

A thrust transmitting member 25 is interposed between the flange 7 of the insertion port 2 and the inward flange 13 of the receiving port 3. As shown in FIG. 2, the thrust transmitting member 25 is formed as an annular integral member. This thrust transmitting agent is formed as a ring of low-expanded polystyrene in which the plastic region is wide and the elastic limit stress changes by changing the expansion ratio. As a material, another resin material having a desired thrust transmitting force and contraction property may be used, and the shape is practically a ring shape having an appropriate thickness and width as shown in the illustrated example.

The thrust transmitting member will be described in more detail. The thrust transmitting member 25 is elastically deformed by a compressive force equivalent to the propulsive force during construction, so that the propulsive force is transmitted, but no distortion remains. When a compressive force equal to or greater than the elastic limit stress acts, the amount of strain increases in the plastic region. Thereafter, when a compressive force equal to or more than a certain value is applied, the progress of the strain is stopped with a predetermined thickness remaining. The elastic limit stress, the range of the plastic region, and the final thickness in the state where the distortion has progressed can be adjusted by the expansion ratio when the thrust transmitting material is a foam material. The following conditions can be considered as a method for setting the expansion ratio.

When the applied pressing force is about the propulsion force, the expansion force is set so that the elastic limit stress σ ₁ has the following relationship because the stress value is within the elastic limit stress (the propulsion force is transmitted normally). For this reason, the thrust transmitting member is not plastically deformed). σ ₁ > (F / A) = σ _max where F: thrust, A: area of thrust transmitting part, σ
_max : stress generated in the thrust transmitting member.

Next, when a large pushing force acts on the joint due to an earthquake or the like, the thrust transmitting member is in the plastic region, so that the amount of distortion of the thrust transmitting member increases. The pushing force generated during this earthquake is 0.3d, which is the force for preventing the seismic joint from coming off.
(Tf): If the same as the (d nominal diameter), as shown in FIG. 4, when the pushing force by the earthquake or the like is applied, the length is compressed thrust transmission member pushing allowance L + L ₁ L ₁
Becomes At this time, if L is set to be 1% of the pipe length, it means that the press-in allowance has been secured. It is needless to say that the provision of the thrust transmitting member prevents stress concentration during curve propulsion, which is the original purpose of the thrust transmitting member.

FIGS. 6 and 7 show stress-strain curves when low-expanded polystyrene is used as the material of the thrust transmitting member. The distortion is increased by a predetermined compression force, and the distortion in the compression direction can secure a sufficient press-in allowance. The low-expanded polystyrene is a material obtained by adding a foaming agent such as propane to polystyrene as a main raw material, has a wide plastic region, and has a property of changing elastic limit stress by changing an expansion ratio. FIG. 7 shows the relationship between the expansion ratio and the stress and strain.
The relationship between the expansion ratio of two types of expanded polystyrene and its mechanical properties is shown.

The method of constructing the joint 1 will be described below. First, as shown in FIG. 3A, the propulsion force transmitting member 25 is deposited on the outer peripheral portion of the insertion port 2. On the other hand, as shown in FIG. 2B, a rubber ring 15 and a lock ring 17 are attached to predetermined positions of the receiving port 3, and the insertion port 2 is inserted into the receiving port 3. Thereafter, the pipe whose insertion port 2 is inserted into the receiving port 3 is sequentially inserted into the sheath by the hydraulic jack in the case of the pipe-in-pipe method, and sequentially inserted while excavating by the leading pipe in the case of the propulsion method. . In this state,
As shown in FIG. 3C, the thrust transmitting member 25 is sandwiched between the flange 7 of the insertion port 2 and the inward flange 13 of the receiving port 3, and the propulsive force of the hydraulic jack is reduced by the thrust transmitting member 25. To the preceding tube. After the propulsion, the thrust transmitting material is left as it is.

FIG. 5 shows an embodiment different from that described above. In this joint, the lock ring 37 of the socket 33 is provided in a lock ring groove 34 provided on the rear end side of the socket with respect to the rubber ring 15. The projection 35 of the insertion opening 32 with which the engagement is formed is formed at an intermediate portion between the lock ring and the rubber ring. The lock ring 37 is fixed by a set bolt 38. The rubber ring 15 is fitted in the rubber ring groove 36. Other parts are substantially the same as those in the previous embodiment.

As described above, the thrust transmitting member 25 only needs to be capable of transmitting the necessary thrust during propulsion and ensuring the amount of expansion and contraction of the joint. The present invention is not limited to the illustrated example. For example, it is conceivable to use a porous ceramic, a metal sintered body, a metal net, or the like instead of the foamed resin.

[0026]

As is apparent from the above description, according to the present invention, the propulsion force can be transmitted to the pipe joint used for the propulsion method, and the pipe joint is crushed when a large compression force is applied after the propulsion is completed. Since the thrust transmitting material whose length is reduced is interposed, a sufficient amount of expansion and contraction is secured after the pipe is buried,
It became extremely effective as a seismic joint.

[Brief description of the drawings]

FIG. 1 is a sectional view of a pipe joint according to the present invention.

FIG. 2 is a sectional view (a) and a front view (b) of the thrust transmitting member.

FIG. 3 is an explanatory view of a joint joining method.

FIG. 4 is an explanatory diagram of a normal state (a) and a state (b) in which a large pressing force is applied.

FIG. 5 is a sectional view of a joint showing a different embodiment.

FIG. 6 is a graph showing a stress-strain curve of low-expansion polystyrene.

FIG. 7 is a graph showing stress-strain curves for various materials.

FIG. 8 is a sectional view of a conventional pipe joint.

FIG. 9 is an explanatory view of a propulsion method.

FIG. 10 is a sectional view of a different conventional pipe joint.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pipe joint 2 Insertion port 3 Reception port 5 Projection 7 Flange 15 Rubber ring 17 Lock ring 25 Thrust transmission material

Claims (4)

[Claims] 1. A propulsion method for burying underground while connecting pipes, wherein a propulsion force can be transmitted between an insertion port and a reception port of the pipe, and a pressing force greater than the propulsion force acts. A propulsion method comprising: interposing a thrust transmitting member which can contract in the axial direction of the pipe when the propulsion force is transmitted to the preceding pipe via the thrust transmitting member. 2. A fitting for connecting a pipe by fitting an insertion port and a receiving port, wherein a rubber ring for sealing a gap between the inner peripheral surface of the receiving port and the outer peripheral surface of the insertion port is provided. A lock ring and an insertion projection that is engaged with the lock ring to prevent the insertion opening from being displaced are provided on the inner peripheral surface of the mouth, and furthermore, a propulsion is provided between the flange provided on the outer periphery of the insertion opening and the receiving end. A pipe joint comprising a thrust transmitting member capable of transmitting a force and contracting in a pipe axis direction by a pressing force larger than the propulsion force. 3. The pipe joint according to claim 2, wherein the thrust transmitting member is a porous member. 4. The thrust transmitting material according to claim 1, wherein the material of the thrust transmitting material is expanded polystyrene.