JP2819224B2 - Reaction force support structure for shaft excavator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a support structure for supporting a propulsion reaction force in a shaft excavator for excavating a shaft for a hydraulic pipeline of a hydroelectric power plant.

[0002]

2. Description of the Related Art Conventionally, in order to excavate a tunnel for forming a hydraulic pipeline of a hydroelectric power plant in mountainous ground, first,
After excavating a small-diameter inclined shaft from below the ground upward, using this inclined shaft as a pilot shaft, reaming (widening) a large-diameter tunnel from above the ground downward, and excavating the excavated soil through the pilot shaft. To be discharged. When excavating a steep inclined shaft that becomes such a pilot well using a tunnel boring machine, the machine tries to retreat by its own weight, and even if the gripper provided on the body of the machine is pressed against the excavation wall surface, When the bedrock is a soft rock layer, a strong crimping force cannot be obtained, and it is extremely dangerous.

For this reason, the applicant of the present application has disclosed in
A reaction force support structure for an inclined shaft excavator as described in Japanese Patent No. 22396 was developed. In this structure, a segment fastened to an inclined shaft wall by an anchor bolt on an inner peripheral surface of a fixed length portion of the inclined shaft wall excavated by the excavator is assembled behind the inclined shaft excavator. A plurality of spacer members corresponding to a plurality of propulsion jacks arranged on the excavator are interposed along a wall surface of the shaft with the excavator.

[0004]

According to the above-described reaction force support structure, the reaction force transmitted to the segment through the spacer member can be firmly supported by the anchor bolts. When the anchor bolt is driven in, when the reaming excavation is performed from the upper side to the lower side after the formation of the shaft, there is a problem that the mechanical excavation cannot be performed due to the presence of the anchor bolt. For this reason, it is necessary to remove the anchor bolt before reaming excavation,
The removal operation requires a great deal of labor and labor.
SUMMARY OF THE INVENTION An object of the present invention is to provide a reaction force support structure in a shaft excavator capable of completely solving such a problem.

[0005]

In order to achieve the above object, a reaction force support structure in a shaft excavator according to the present invention projects outward on an outer surface into a shaft shaft excavated by the shaft excavator. Assemble a plurality of molds forming a locking surface into a ring shape, fill concrete between the ring-shaped formwork and the shaft wall, cure it to form a reaction force support, The support jack is configured to receive a shield jack of an inclined shaft excavator at a front end face thereof.

[0006]

The weight of the shaft excavator acts on the reaction force support through the shield jack. The reaction force support is made of a mold assembled in a ring shape, and concrete formed by filling and hardening between the outer surface of the mold and the inclined shaft wall. Since the locking surface part is provided,
The adhesive force (locking force) between the concrete and the formwork is increased, and the ground receives the propulsion reaction force of the inclined shaft excavator firmly through the adhesive force. Further, the rear formwork to which the reaction force is no longer applied is removed, transported forward, and assembled again to be used for supporting the reaction force.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
1 is a reaction force support formed in the inclined shaft wall 2 excavated by the inclined shaft excavator 6 at the back of the inclined shaft excavator 6. A ring-shaped form 3A formed by assembling in the circumferential direction along the wall surface, and a plurality of rows of the ring-shaped forms 3A are connected in series only to a fixed length of the inclined shaft wall 2, and these ring-shaped forms 3A are formed. The lining concrete 4 is filled and hardened between the formwork 3A and the shaft wall 2.

As shown in FIG. 2, both sides of the form 3 are inclined so as to be wider or narrower from the front end to the rear end, so that the shape of the form 3 is fan-shaped, and the form 3 is formed in the width direction. Is formed in the locking surface portion 5 by inclining the outer surface, which is the side facing the inclined shaft wall 2, outwardly from the front end surface to the rear end surface so as to be thicker. It is. Note that the locking surface portion 5 may be inclined in a direction of increasing the thickness from the rear end surface to the front end surface of the mold 3, and as shown in FIG. A surface portion composed of the locking projection 5a may be provided in a protruding manner.

[0009] The shaft excavator 6 has a cylindrical front body 6a,
A middle body part 6b and a rear body part 6c are connected in series, a rotation drive mechanism for the cutter plate 7 is disposed in the front body 6a, and the front body part 6a and the rear body part 6c are connected to the middle body part. It is connected telescopically and flexibly via a 6b, and further connected between the front body 6a and the rear body 6c by thrust jacks 8 arranged in four directions. A front gripper 9 which protrudes and retracts from the inside of the body toward the inclined wall 2 by operating a hydraulic cylinder (not shown) at appropriate intervals in the circumferential direction is provided on a peripheral wall of the front body part 6a and the rear body part 6c. Each gripper 10 is provided.

Reference numeral 11 denotes a shield jack arranged and fixed on the inner peripheral surface of the rear trunk portion 6c, and a spreader 12 mounted on the rod end thereof is brought into contact with the front end surface of the form 3 of the reaction force support 1. Contact and acceptance. Further, press jacks 13 are alternately arranged on all sides with the shield jacks 11, and an annular shape in which the rod ends of the press jacks 13 contact the front end face of the lining concrete 4 of the reaction force support 1. The wife formwork 14 is fixed. 15 is the rear end of the front torso 6a and the middle torso 6b
Are a plurality of direction correcting jacks that are connected between the front ends. Reference numeral 16 denotes a chute for excavating earth and sand formed with a front end opening formed at an intake for sediment excavated by the cutter plate 7.
(Shown in FIG. 9).

In order to excavate the inclined shaft 21 in the hard bedrock by the inclined shaft excavator 6 configured as described above, the rods of the shield jack 11 and the press jack 13 are contracted as shown in FIG. The spreader 12 and the end form 14 fixed to the ends are brought into contact with the form 3 of the reaction force support 1 and the front end face of the cast concrete 4, respectively, and the front gripper 9 is further moved inside the front body 6a. The main gripper 10 protrudes from the rear trunk 6c, and the shaft 2
And the inclined shaft excavator 6 is supported by the inclined shaft wall 2. By extending the thrust jack 8 while rotating the cutter plate 7 in this state, the rear trunk portion is extended.
The front trunk 6a is advanced with respect to 6c, and the shaft 21 is excavated.

When a fixed length of the shaft 21 is excavated, as shown in FIG. 5, the front gripper 9 is protruded from the front body portion 6a and is pressed against the shaft wall 2 so that the shaft excavator 6 is moved by the shaft wall 2. After being supported, the main gripper 10 is retracted to be separated from the inclined shaft wall 2, and thereafter, while the thrust jack 8 is contracted, the shield jack 11 and the press jack 13 are extended in accordance with the contraction amount, thereby making the rear body part. Move 6c forward a certain length.

Next, as shown in FIG. 6, the main gripper 10 is pressed against the shaft wall 2 and the shield jack 11 is pressed.
Then, after the rod of the press jack 13 is contracted to provide a space 18 between the rod end and the frontmost mold 3 where the next mold 3 can be assembled, the mold 3 is placed in this space 18. Carry in to assemble the ring-shaped formwork 3A. As these molds 3, the molds 3 obtained by disassembling the last ring-shaped mold 3A and removing it from the lining concrete 4 are used. Form 3
At the time of assembling, the rod of the shield jack 11 only at the place to be assembled may be contracted, and the spreader 12 of the other shield jack 11 may be brought into contact with the front end face of the mold 3.

After assembling the ring-shaped form 3A in the space 18 in this way, as shown in FIG. 7, a hose 20 is connected and communicated with a concrete pouring hole 19 drilled at an appropriate position on the form 3, and the inclined shaft Concrete 4A is cast between the shaft wall 2 and the ring-shaped form 3A through the hose 20 from inside. At this time, the rod of the press jack 13 is extended, and the end form 14 is inserted into the gap between the inclined wall 2 and the ring form 3A, and the end form 14 is gradually moved according to the placement of the concrete 4A. It is retracted and concrete is poured to the substantially front end of the ring-shaped formwork 3A.

After the concrete 4A is cast, the press jack 13 is extended in a state where the shaft excavator 6 is supported on the shaft wall 2 via the main gripper 10, thereby moving the end form 14 backward. And pressurize the concrete 4A
Perform tamping. By extending the thrust jack 8 after compacting the cast concrete 4A or in parallel with the work, as shown in FIG. 4, the front body 6a of the shaft excavator 6 is advanced to excavate the shaft 21. .

As described above, the shaft 21 due to the forward movement of the front body 6a
Excavation, formation of the formwork assembling space 18 by advancing the rear trunk portion 6b after the excavation, assembling of the formwork 3 into the space 18;
While repeatedly laying the concrete 4A and excavating the shaft 21 by advancing the front trunk portion 6a, the shaft 21 is excavated upward from below. At this time, even if the pressing force of the front gripper 9 or the main gripper 10 against the inclined wall 2 is weak, or if the grippers 9 and 10 do not operate, the spreader of the shield jack 11 of the inclined shaft excavator 6 can be used.
The form 3 of the reaction force support 1 receiving the support 12 firmly adheres to the hardened concrete 4 by a frictional locking force with a projection or an inclined surface formed on the outer surface of the form 3. And
Moreover, since the concrete 4 is integrally fixed to the inclined shaft wall 2, the concrete 4 can safely support the inclined shaft excavator 6.

Next, the pit excavator 6 is gripped by the grippers 9 and 10 such as the ground where the rock easily collapses or the soft rock.
When excavating the ground that cannot sufficiently support its own weight, as shown in FIG. 4 above, when excavating the shaft 21, the rods of the shield jack 11 and the press jack 13 are contracted as shown in FIG. Reaction support 1 already formed with a spreader 12 and an annular wand form 14 fixed to the part
Abuts against and receives the front end surfaces of the formwork 3 and the lining concrete 4, respectively, and is fixed to the inclined shaft wall 2 through the locking force between the hardened lining concrete 4 and the locking surface 5 of the formwork 3. On the other hand,
It is assumed that the inclined shaft excavator 6 is supported.

Further, the front gripper 9 is immersed in the front body 6a, and the main gripper 10 is protruded from the rear body 6c to be pressed against the wall of the inclined shaft wall 2, and in this state, the cutter plate 7 is rotated while rotating the thrust. By extending the jack 8, the front body 6a is advanced with respect to the rear body 6c, and the shaft 21 is excavated.

When a fixed length of the shaft 21 is excavated, as shown in FIG. 5, the front gripper 9 is protruded from the front body 6a and is pressed against the shaft wall 2 so that the shaft excavator 6 is moved by the shaft wall 2. At the same time, the main gripper 10 is retracted and separated from the inclined shaft wall 2 and thereafter, the shield jack 11, the spreader 12 of the press jack 13 and the annular wand form 14 are pressed against the reaction force support 1, and the inclined shaft excavator The rear trunk 6c is advanced by a predetermined length by extending these rods while supporting the rod 6, and contracting the thrust jack 8 according to the amount of extension.

Next, as shown in FIG. 6, the main gripper 10 is pressed against the inclined shaft wall 2 and the rod of the press jack 13 is contracted. On the other hand, in the reaction force support 1 composed of the serial ring-shaped formwork 3A of a fixed length that supports the propulsion reaction force of the inclined shaft excavator 1, the rearmost ring-shaped formwork 3A is disassembled as described above, The plurality of molds 3 constituting the mold 3A are transported to a mold assembly position in front.

As shown in FIG. 8, the form 3 is first assembled by contracting a rod of an arbitrary shield jack 11 to form a form assembling space 18, and through this space 18, the form is formed on the inclined wall surface. 3 is connected to the front end face side of the opposed formwork 3 of the ring-shaped formwork 3A already assembled. At this time, the spreader 12 of the remaining shield jack 11 is brought into contact with the front end face of the form 3 of the reaction force support 1 to support the shaft excavator 6. Then, the rod of the shield jack 11 located at the form assembling site is contracted in accordance with the assembling order of the form 3, and another shield jack 11 is connected to the front end face of the form 3 of the reaction force support and the form 3 of the form 3 already assembled. Let it be received on the front end face.

After assembling the ring-shaped formwork 3A at the forefront of the reaction force support 1, the concrete 4A is cast between the shaft wall 2 and the ring-shaped formwork 3A in the same manner as described above. At this time, the rod of the press jack 13 is extended, and the end form 14 is inserted into the gap between the inclined wall 2 and the ring form 3A, and the end form 14 is gradually moved according to the placement of the concrete 4A. After retreating and casting concrete to approximately the foremost end of the ring-shaped formwork 3A, the cast formwork 4A is pressed by moving the wife formwork 14 rearward and compacted. By extending the thrust jack 8 after compacting the cast concrete 4A or in parallel with the work, as shown in FIG. 4, the front body 6a of the shaft excavator 6 is advanced to excavate the shaft 21. .

For excavation of soft ground where the support of the inclined shaft excavator 6 by the front gripper 9 and the main gripper 10 can hardly be obtained, the reaction force support 1 can be used without using these grippers 9 and 10. The shaft 21 can be excavated while the shaft excavator 6 is supported. That is, both the grippers 9 and 10 are immersed in the machine, and the thrust jack 8 is constantly contracted. In this state, the shield jack 11 is supported on the front end face of the reaction force support 1 while supporting the propulsion reaction force. Is extended, and the shaft excavator 6 is excavated.

After excavating for a certain length, the shield jack located at the formwork assembling site in the same manner as described above in accordance with the assembling order of the formwork 3
If the rod of 11 is contracted, another shield jack 11 is brought into contact with the front end face of the form 3 of the reaction force support body and the front end face of the formwork 3 already assembled to support the weight of the shaft excavator 6. Good. The concrete placement, compaction, etc. are the same as in the above embodiment. In this way, the small-diameter shaft 21 is excavated from the work base 17 side diagonally upward to a predetermined height by the shaft-shape excavator 6, and then the large-diameter reaming portion 22 (shown in FIG. 8) is inclined using the shaft 21 as a pilot shaft. Excavate downward.

[0025]

As described above, according to the reaction force support structure of the inclined shaft excavator of the present invention, the outwardly projecting locking surface portion is formed on the outer surface of the inclined shaft wall excavated by the inclined shaft excavator. A plurality of formwork is assembled in a ring shape, concrete is filled between the ring-shaped formwork and the inclined shaft wall and hardened to form a reaction force support, and a front end face of the reaction force support is formed. Since it is configured to receive the shield jack of the inclined shaft excavator, the cast concrete of the reaction force support bites into the rough wall surface of the inclined shaft wall in the anchor state and becomes firmly fixed and integrated, In addition, the cast concrete and the formwork are similarly firmly fixed and integrated via an outwardly protruding engaging surface provided on the outer surface of the formwork, so that the reaction force The support ensures that the weight of the shaft excavator is received One in which it is bet.

Furthermore, the above-mentioned support for supporting the propulsion reaction force of the inclined shaft excavator does not fix the segments to the excavated inclined shaft wall by means of anchor bolts as in the prior art, but forms the frame by concrete through the inclined shaft wall surface. In this way, reaming excavation by mechanical excavation becomes possible, and a large-diameter inclined shaft such as a hydraulic pipeline of a hydroelectric power plant can be efficiently excavated. In addition, the reaction force support is only required to be long enough to support the inclined shaft excavator, and since the formwork can be dismantled, the last formwork was removed according to the excavation of the inclined shaft excavator. Thereafter, it can be conveyed forward and used again as a reaction force support, and an economical reaction force support structure in which the number of parts used is minimized can be formed.

[Brief description of the drawings]

FIG. 1 is a simplified longitudinal side view of a shaft excavator and a reaction force support,

FIG. 2 is an assembly view and a partial development view of a ring-shaped form,

FIG. 3 is a simplified perspective view showing another embodiment of the locking surface portion of the mold;

FIG. 4 is a simplified vertical sectional side view showing a state of excavation of a shaft shaft;

FIG. 5 is a simplified vertical sectional side view of a state in which a rear trunk is advanced,

FIG. 6 is a simplified vertical sectional side view showing a form assembling state;

FIG. 7 is a simplified longitudinal side view showing a concrete filling state,

FIG. 8 is a simplified vertical sectional side view showing a form assembling state;

FIG. 9 is a simplified vertical cross-sectional side view of the entire shaft being excavated.

FIG. 10 is a vertical sectional front view of a shaft and a reaming excavation part.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reaction force support 2 Shaft wall 3 Formwork 4 Concrete 5 Locking surface part 6 Shaft shaft excavator 8 Thrust jack 9 Front gripper 10 Main gripper 11 Shield jack 13 Press jack

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-311983 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) E21D 9/02 E21D 11/10

Claims (1)

(57) [Claims] 1. A reaction force support structure provided at a rear end side of a shaft excavator to support a propulsion reaction force of the shaft excavator, wherein the reaction force support structure is provided inside a shaft shaft excavated by the shaft excavator and on an outer surface thereof. Assembling a plurality of formwork with a locking surface protruding outward into a ring shape, filling concrete between this ring-shaped formwork and the shaft wall and curing to form a reaction force support A reaction support structure for a shaft excavator, wherein the shield jack of the shaft excavator is received at a front end face of the reaction support body.