JP2014237989A - Backing prevention structure of propulsion pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a backing prevention structure capable of reducing connection parts of a bearing member and a propulsion pipe and shortening work time required for connecting the bearing member and the propulsion pipe.SOLUTION: A backing prevention structure 10 of a propulsion pipe 20 used in a jacking method in which the propulsion pipe 20 is pushed into the ground includes: a bearing member 11 having a contact part 15 coming in contact with an outer face 21b of the propulsion pipe 10 and fixed to a start area of the propulsion pipe 20; and a fixture 12 having a fitting part 12a fitted in an injection hole 22 of a grout formed in a wall part 21 of the propulsion pipe 20. A fitting part 12d inserted in a fitting hole 15c of the contact part 15 is projectedly provided on the fitting part 12a.

Description

  The present invention relates to a reverse travel prevention structure for a propulsion pipe.

  In the propulsion method, the main push jack is pressed against the propulsion pipe, the propulsion pipe is pushed into the ground, and the propulsion pipes are added sequentially to embed a pipe body connecting multiple propulsion pipes in the ground. Yes.

When a propulsion pipe is added in the propulsion method, a main push jack is separated from the rearmost propulsion pipe to form a space behind the propulsion pipe, and another propulsion pipe is installed in this space.
Since the frictional resistance of the propulsion pipe against the ground is small during the initial excavation, the propulsion pipe is pushed backward by earth pressure and water pressure acting on the front of the excavator and blade edge when the main jack is separated from the propulsion pipe. There is a risk that.

  The structure for preventing the propulsion pipe from moving backward includes a support member disposed outside the propulsion pipe and a cylindrical fitting portion inserted into a grout injection hole formed in the propulsion pipe. Some end surfaces are welded to the support member (see, for example, Patent Document 1).

Japanese Patent No. 5116111

  In the above-described conventional reverse travel prevention structure, it is difficult to sufficiently secure the strength of the support member and the fitting portion, and therefore, there are many parts for connecting the support member and the propulsion pipe, and the connection between the support member and the propulsion pipe is increased. There is a problem that the work time required for the process becomes longer.

  The present invention provides a reverse travel prevention structure that solves the above-described problems, can reduce the number of connection parts between the support member and the propulsion pipe, and can reduce the work time required to connect the support member and the propulsion pipe. The task is to do.

  In order to solve the above-mentioned problems, the present invention is a structure for preventing the backward movement of a propulsion pipe used in a propulsion method in which the propulsion pipe is pushed into the ground by a main push jack, and has a contact portion that comes into contact with the outer surface of the propulsion pipe. And a support member fixed to the structure provided in the starting region of the propulsion tube, and a jig having a fitting portion fitted in a grout injection hole formed in the wall portion of the propulsion tube. The fitting portion is provided with a fitting portion that is inserted into the fitting hole of the contact portion.

  In this configuration, when a backward load is applied to the propulsion tube, the reaction point (shearing force) acting between the contact portion of the support member and the fixture mounting portion is the outer surface of the propulsion tube. Therefore, the bending moment acting on the jig can be reduced. Moreover, since the pressure receiving area of the fitting portion is increased, the allowable resistance force of the jig can be increased. Therefore, in this invention, the connection part of a support member and a propulsion pipe can be decreased, and the working time required for the connection of a support member and a propulsion pipe can be shortened.

  In the above-described structure for preventing the reverse movement of the propulsion pipe, when the injection hole has a tapered portion that gradually increases in diameter from the inner surface side portion of the wall portion toward the opening portion of the outer surface, the fitting portion It is desirable to increase the contact area between the outer peripheral surface of the fitting portion and the inner peripheral surface of the injection hole by forming the shape of the truncated cone.

  In the above-described structure for preventing the reverse movement of the propulsion pipe, when a cylindrical socket is fitted into the injection hole and a thread groove is formed on the inner peripheral surface of the socket, the fitting portion is screwed into the socket. By forming the screw part to be joined, the fitting part can be stabilized with respect to the injection hole.

  As another configuration of the present invention, the structure is a propulsion pipe reverse prevention structure used in the propulsion method for pushing the propulsion pipe into the ground by the main push jack, and has a contact portion that comes into contact with the outer surface of the propulsion pipe, A support member fixed to a structure provided in a starting region of the propulsion tube, a jig having a cylindrical fitting portion fitted in a grout injection hole formed in a wall portion of the propulsion tube, and A mounting bolt inserted into the fitting portion and fixed to the abutting portion, and the injection hole is a taper that gradually increases in diameter from the inner surface side portion of the wall portion toward the opening portion of the outer surface. The fitting member is formed in a truncated cone shape.

  In this configuration, when a backward load acts on the propulsion pipe, the point of action of the reaction force (shearing force) acting between the contact portion of the support member and the mounting bolt is close to the outer surface of the propulsion pipe. Therefore, the bending moment acting on the mounting bolt can be reduced. Moreover, since the pressure receiving area of the fitting portion is increased, the allowable resistance force of the jig can be increased. Therefore, in this invention, the connection part of a support member and a propulsion pipe can be decreased, and the working time required for the connection of a support member and a propulsion pipe can be shortened.

  In the structure for preventing the backward movement of the propulsion pipe of the present invention, the bending moment acting on the jig can be reduced and the allowable resistance of the jig can be increased, so that the number of connecting portions between the support member and the propulsion pipe is reduced. The working time required for the connection between the support member and the propulsion pipe can be shortened.

It is the sectional side view which showed the excavation machine, propulsion pipe, and reverse travel prevention structure of 1st embodiment. It is the top view which showed the excavation machine, propulsion pipe, and reverse travel prevention structure of 1st embodiment. It is AA sectional drawing of FIG. 1 which showed the propulsion pipe | tube of 1st embodiment, and the reverse travel prevention structure. It is the figure which showed the reverse travel prevention structure of 1st embodiment, (a) is an expanded sectional side view, (b) is an enlarged plan view. It is the perspective view which showed the jig | tool and washer of 1st embodiment. (A) is the sectional side view which showed the other structure of the backward movement prevention structure of 1st embodiment, (b) is the expanded sectional side view which showed the backward movement prevention structure of 2nd embodiment.

Embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
In the description of each embodiment, the same constituent elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[First embodiment]
As shown in FIG. 1, the reverse travel prevention structure 10 of the first embodiment prevents the propulsion pipe 20 and the excavator 30 from being pushed back during the initial excavation of the propulsion method.
In the following description, after explaining the outline of the propulsion method, the reverse travel prevention structure 10 will be described in detail.

  In the propulsion method, the propulsion pipe 20 is abutted against the rear end portion of the excavator 30, and the propulsion pipe 20 and the excavator 30 are pushed into the ground 1 by a plurality of main push jacks 40, and the propulsion pipe 20 is sequentially added. Then, the pipe body connecting the plurality of propulsion pipes 20 is embedded in the ground 1.

  In the excavator 30, a cutter 31 is disposed at a front end portion of a cylindrical body portion 33, and a driving device 32 of the cutter 31 is accommodated in the cylindrical body portion 33. The excavating machine 30 excavates the ground 1 by applying a propulsive force by a former push jack 40 described later.

  The propulsion pipe 20 is a cylindrical member embedded in the ground 1. The propulsion pipe 20 is made of, for example, concrete, steel, or ductile cast iron. The propulsion pipe 20 is abutted against the rear end portion of the excavator 30 and is pushed into the ground 1 together with the excavator 30 by applying a propulsive force by a main push jack 40 described later.

As shown in FIG. 3, an injection hole 22 for injecting grout between the outer surface 21 b of the propulsion pipe 20 and the ground 1 penetrates the wall portion 21 of the propulsion pipe 20 in the radial direction. The propulsion tube 20 of the present embodiment is formed with three injection holes 22 on the upper and left and right sides. The injection holes 22 are arranged at intervals of 90 degrees in the circumferential direction of the propulsion tube 20.
Since each injection hole 22 has the same shape, in the following description, the upper injection hole 22 will be described in detail, and the description of the left and right injection holes 22 will be omitted.

As shown in FIG. 4A, the injection hole 22 is formed with an outer tapered portion 23, an intermediate hole portion 24, and an inner tapered portion 25 on the same axis.
The outer tapered portion 23 opens to the outer surface 21 b of the wall portion 21, and the inner tapered portion 25 opens to the inner surface 21 a of the wall portion 21. The axial length (depth) of the inner tapered portion 25 is smaller than the axial length (depth) of the outer tapered portion 23. An intermediate hole portion 24 is formed between the outer tapered portion 23 and the inner tapered portion 25.

The intermediate hole portion 24 is a straight hole portion formed to have the same diameter over the entire length. A cylindrical socket 26 is fixed to the inner peripheral surface of the intermediate hole portion 24.
A thread groove is formed on the inner peripheral surface of the socket 26. The socket 26 is a member to which a coupling fitting or a lid member of a grout supply hose is screwed.

An end of the outer tapered portion 23 on the side of the intermediate hole 24 is formed to have the same inner diameter as the intermediate hole 24. Further, the opening 23 a of the outer tapered portion 23 is larger in diameter than the inner diameter of the intermediate hole portion 24.
The outer tapered portion 23 is gradually enlarged in diameter from the end on the intermediate hole portion 24 side toward the opening 23a. Therefore, the inner peripheral surface of the outer tapered portion 23 is formed in a tapered shape having a diameter gradually increased from the end portion on the intermediate hole portion 24 side toward the opening portion 23a.

A bottom surface 25b having a diameter larger than that of the intermediate hole portion 24 is formed at an end portion of the inner tapered portion 25 on the intermediate hole portion 24 side, and the intermediate hole portion 24 opens at a center portion of the bottom surface 25b. In addition, the opening 25 a of the inner tapered portion 25 is larger in diameter than the inner diameter of the intermediate hole portion 24.
The inner tapered portion 25 is gradually enlarged in diameter from the bottom surface 25b toward the opening 25a. Therefore, the inner peripheral surface of the inner tapered portion 25 is formed in a tapered shape having a diameter that gradually increases from the bottom surface 25b toward the opening 25a.

As shown in FIG. 1, the main push jack 40 imparts a propulsive force to the propulsion pipe 20 and the excavator 30. The cylinder 42 of the main push jack 40 is fixed to the side surface of the start shaft 2, and the rod 41 is movable forward and backward with respect to the cylinder 42 in the excavating direction of the excavator 30.
A strut 43 and a push ring 44 are interposed between the tip end portion of the rod 41 of each main push jack 40 and the rear end face of the rearmost propulsion pipe 20. And the propulsive force can be provided to the propulsion pipe 20 and the excavator 30 by extending the rod 41 of each main push jack 40.

  The reverse travel prevention structure 10 is installed in the start shaft 2. A rearmost propulsion pipe 20 is fixedly connected to the reverse travel prevention structure 10. When each of the main push jacks 40 is separated from the propulsion pipe 20, the reverse movement prevention structure 10 supports the propulsion pipe 20, thereby preventing the propulsion pipe 20 and the excavator 30 from being pushed back backward.

  As shown in FIG. 3, the reverse travel prevention structure 10 includes a support member 11 erected in the start shaft 2, a jig 12 and a washer 13 fitted in the injection hole 22 of the propulsion pipe 20, And a mounting bolt 14 inserted through the washer 13.

The support member 11 is a gate-shaped frame body that includes left and right columns 11a and 11b that are erected on the floor slab of the start shaft 2, and upper beams 11c that are installed on the upper ends of both columns 11a and 11b. It is. The propulsion pipe 20 is inserted into a region surrounded by the floor plate of the support member 11 and the start shaft 2 (see FIG. 1).
As shown in FIG. 2, oblique members 11d attached to the support pillars 11a and 11b are provided at the rear ends of both support pillars 11a and 11b. (See FIG. 1).

Abutting portions 15 project from the front surfaces of both the columns 11a and 11b and the upper beam 11c. As shown in FIG. 3, each abutment portion 15 is disposed so as to face the opening portions 23 a (see FIG. 4A) of the three injection holes 22 of the propulsion tube 20.
In addition, since each contact part 15 is the same structure, in the following description, the contact part 15 of the upper beam 11c is demonstrated in detail, and description is abbreviate | omitted about the contact part 15 of both the support | pillars 11a and 11b.

  As shown in FIG. 4B, the abutment portion 15 stands on the bottom plate 15a protruding from the front surface of the upper beam 11c toward the front (the digging direction of the propelling pipe 20), and on both left and right edges of the bottom plate 15a. And a pair of ribs 15b provided. The rear edges of both ribs 15b are attached to the front surface of the upper beam 11c.

As shown in FIG. 4A, the bottom plate 15 a is disposed so as to face the opening 23 a of the injection hole 22. The inner surface (lower surface) of the bottom plate 15 a is in contact with the outer surface 21 b of the propulsion tube 20.
A circular mounting hole 15c passes through the center of the bottom plate 15a. The mounting hole 15 c is disposed concentrically with the injection hole 22.

  The jig 12 is a cylindrical member (see FIG. 5), and protrudes into the frustoconical fitting portion 12a fitted in the outer tapered portion 23 of the injection hole 22 and the outer end surface 12c of the fitting portion 12a. The provided mounting portion 12d is formed.

The outer diameter of the inner end face 12 b of the fitting part 12 a is formed to be the same as the inner diameter of the intermediate hole part 24. Further, the outer diameter of the outer end surface 12 c of the fitting portion 12 a is formed to be the same as the inner diameter of the opening 23 a of the outer tapered portion 23.
As shown in FIG. 5, the outer peripheral surface of the fitting part 12a is formed in the taper shape gradually diameter-expanded toward the outer end surface 12c from the inner end surface 12b.

  Furthermore, as shown to Fig.4 (a), the length from the inner end surface 12b of the fitting part 12a to the outer end surface 12c is formed the same as the length of the axial direction of the outer side taper part 23. FIG. When the fitting portion 12 a is fitted into the outer tapered portion 23, the outer peripheral surface of the fitting portion 12 a is in close contact with the inner circumferential surface of the outer tapered portion 23.

  At the center of the outer end surface 12c of the fitting portion 12a, a mounting portion 12d that protrudes through the mounting hole 15c of the contact portion 15 is projected. An insertion hole 12e passes through the center of the fitting portion 12a and the attachment portion 12d (see FIG. 5).

The washer 13 is a truncated cone-shaped member that is fitted into the inner tapered portion 25 of the injection hole 22. The outer diameter of the inner end surface 13 b of the washer 13 is formed to be the same as the outer diameter of the bottom surface 25 b of the inner tapered portion 25. Further, the outer diameter of the outer end surface 13 c of the washer 13 is formed to be the same as the inner diameter of the opening 25 a of the inner tapered portion 25.
As shown in FIG. 5, the outer peripheral surface of the washer 13 is formed in a tapered shape that gradually increases in diameter from the inner end surface 13 b toward the outer end surface 13 c.

  Furthermore, as shown to Fig.4 (a), the length from the inner end surface 13b of the washer 13 to the outer end surface 13c is formed the same as the length of the inner side taper part 25 in the axial direction. When the washer 13 is fitted into the inner tapered portion 25, the outer peripheral surface of the washer 13 is in close contact with the inner peripheral surface of the inner tapered portion 25. Further, an insertion hole 13 e passes through the center of the washer 13.

The mounting bolt 14 is inserted through the insertion hole 12 e of the jig 12 and the insertion hole 13 e of the washer 13.
The outer end portion of the mounting bolt 14 protrudes from the mounting portion 12 d of the jig 12 and is inserted through a through hole of the mounting plate 14 c that is superimposed on the outer surface of the bottom plate 15 a of the contact portion 15. Further, the inner end portion of the mounting bolt 14 protrudes from the outer end surface 13 c of the washer 13.
A nut 14 b is screwed to the outer end portion of the mounting bolt 14, and a nut 14 a is screwed to the inner end portion of the mounting bolt 14. Thereby, the contact part 15, the jig 12 and the washer 13 are fixed to the propulsion pipe 20.

  In the reverse travel prevention structure 10 as described above, as shown in FIG. 1, when the propulsion pipe 20 is added, a backward load acts on the propulsion pipe 20 due to earth pressure or water pressure acting on the front surface of the excavator 30. Then, as shown in FIG. 3, the load is transmitted from the inner peripheral surface of the injection hole 22 to the support member 11 through the jig 12. Thus, since the propulsion pipe 20 is supported by the support member 11, the propulsion pipe 20 and the excavator 30 can be prevented from being pushed back.

Further, in the reverse travel prevention structure 10, as shown in FIG. 4A, when a backward load is applied to the propulsion pipe 20, the contact portion 15 of the support member 11 and the mounting portion 12d of the jig 12 are connected. Since the point of reaction force (shearing force) acting between them is in the vicinity of the outer surface 21b of the propulsion tube 20, the bending moment acting on the jig 12 can be reduced.
Further, the fitting portion 12a of the jig 12 is formed in a truncated cone shape corresponding to the outer tapered portion 23, and the pressure receiving area of the fitting portion 12a is increased, so that the allowable resistance force of the jig 12 is increased. be able to.
Therefore, in the reverse travel prevention structure 10 of the first embodiment, the number of connecting parts between the support member 11 and the propulsion pipe 20 can be reduced, and the work time required for the connection between the support member 11 and the propulsion pipe 20 can be shortened. it can.

  Further, in the reverse travel prevention structure 10, since the contact portion 15 of the support member 11 is in contact with the outer surface 21 b of the propulsion tube 20, a backward load acts on the propulsion tube 20, and the load is transmitted to the support member 11. Then, the contact portion 15 is pressed against the outer surface 21 b of the propulsion pipe 20 by the bending moment (arrow B) generated in the support member 11. That is, the bending moment of the support member 11 is converted into a surface pressure that compresses the propulsion pipe 20 in the radial direction. Thereby, since the reaction force which acts on the jig | tool 12 from the support member 11 becomes small, the bending moment which generate | occur | produces in the jig | tool 12 can be made small.

As mentioned above, although 1st embodiment of this invention was described, this invention is not limited to said 1st embodiment, In the range which does not deviate from the meaning, it can change suitably.
For example, in the first embodiment, as shown in FIG. 4A, the fitting portion 12a of the jig 12 is formed in a truncated cone shape, but the injection hole 22 is formed in a cylindrical shape. May form the fitting part 12a in a cylindrical shape without making the outer peripheral surface of the fitting part 12a into a tapered shape.

  In the first embodiment, as shown in FIG. 5, the outer diameter of the mounting portion 12d is smaller than the outer diameter of the outer end surface 12c of the fitting portion 12a. You may form in the same magnitude | size as the outer diameter of the end surface 12c.

  In addition, as shown in FIG. 6A, when the screw portion 12 f that is screwed into the socket 26 is formed in the jig 12, the jig 12 can be stabilized with respect to the injection hole 22.

  Moreover, in 1st embodiment, as shown to Fig.4 (a), although the inner end part of the attachment bolt 14 is attached to the washer 13, the inner surface of the propulsion pipe 20 is provided between the washer 13 and the nut 14a. You may interpose the attachment board contact | abutted to 21a.

In the first embodiment, the jig 12 and the washer 13 are fitted in the injection hole 22, but only the jig 12 may be fitted in the injection hole 22.
When only the jig 12 is fitted in the injection hole 22, the attachment portion 12 d of the jig 12 is inserted into the attachment hole 15 c of the contact portion 15 and engaged without using the attachment bolt 14. May be.

  Further, the shape of the mounting plate 14c is not limited. Further, if the force is transmitted from the jig 12 to the contact portion 15 without the jig 12 coming out of the injection hole 22, the mounting plate 14c may not be provided.

[Second Embodiment]
As shown in FIG. 6B, the reverse movement preventing structure 10 </ b> A of the second embodiment is a jig having a support member 11 and a truncated cone-shaped fitting portion 12 a that fits inside the outer tapered portion 23 of the injection hole 22. 12 and a mounting bolt 16 inserted into the insertion hole 12e of the fitting portion 12a. In the second embodiment, the mounting bolt 16 is fixed to the abutting portion 15 of the support member 11 by screwing the nut 16 b into the outer end portion of the mounting bolt 16. The mounting bolt 16 is screwed into the socket 26.

  In the reverse travel prevention structure 10A of the second embodiment, the fitting portion 12a of the jig 12 is formed in a truncated cone shape corresponding to the outer tapered portion 23, and the pressure receiving area of the fitting portion 12a is increased. The allowable resistance force of the tool 12 and the mounting bolt 16 can be increased. Therefore, the connection part of the support member 11 and the propulsion pipe 20 can be reduced, and the work time required for the connection of the support member 11 and the propulsion pipe 20 can be shortened.

  The second embodiment can be changed as appropriate without departing from the spirit of the second embodiment, as in the first embodiment.

DESCRIPTION OF SYMBOLS 1 Ground 2 Starting shaft 10 Reverse structure (1st embodiment)
10A Reverse travel prevention structure (second embodiment)
DESCRIPTION OF SYMBOLS 11 Support member 11a, 11b Support | pillar 11c Upper beam 12 Jig 12a Fitting part 12b Mounting part 12e Insertion hole 13 Inner fitting member 13d Insertion hole 14 Mounting bolt (1st embodiment)
14a, 14b Nut 15 Contact part 15a Bottom plate 15c Mounting hole 16 Mounting bolt (second embodiment)
DESCRIPTION OF SYMBOLS 20 Propulsion pipe 21 Wall part 22 Injection hole 23 Outer taper part 23a Opening part 24 Intermediate hole part 25 Inner taper part 25a Opening part 26 Socket 30 Excavator 31 Cutter 32 Drive device 40 Former push jack 41 Rod

Claims (4)

A structure for preventing the backward movement of the propulsion pipe used in the propulsion method in which the propulsion pipe is pushed into the ground by a former push jack,
A support member that has an abutting portion that abuts against an outer surface of the propelling tube, and is fixed to a structure provided in a starting region of the propelling tube;
A jig having a fitting portion fitted in a grout injection hole formed in the wall portion of the propulsion tube,
A structure for preventing the backward movement of the propulsion pipe, wherein the fitting portion is provided with a fitting portion that is inserted into a fitting hole formed in the contact portion. The injection hole has a tapered portion that gradually increases in diameter from the portion on the inner surface side of the wall portion toward the opening on the outer surface,
The structure for preventing the reverse movement of the propulsion pipe, wherein the fitting portion is formed in a truncated cone shape. A cylindrical socket is fitted in the injection hole,
A thread groove is formed on the inner peripheral surface of the socket,
The propulsion pipe reverse movement prevention structure according to claim 1 or 2, wherein the fitting portion is formed with a screw portion that is screwed into the socket. A structure for preventing the backward movement of the propulsion pipe used in the propulsion method in which the propulsion pipe is pushed into the ground by a former push jack,
A support member that has an abutting portion that abuts against an outer surface of the propelling tube, and is fixed to a structure provided in a starting region of the propelling tube;
A jig having a cylindrical fitting portion fitted in a grout injection hole formed in the wall portion of the propulsion tube;
A mounting bolt inserted into the fitting portion and fixed to the contact portion,
The injection hole has a tapered portion that gradually increases in diameter from the inner surface side portion of the wall portion toward the opening on the outer surface;
The structure for preventing the reverse movement of the propulsion pipe, wherein the fitting member is formed in a truncated cone shape.

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