JPH0692717B2 - Tunnel construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a tunnel construction method by a cast-in-place concrete lining shield method.

(Prior Art) In the Japanese Patent Publication No. 54-33656, the applicants proceeded by a shield excavator equipped with two rows of propelling jacks and concrete press jacks along the inner and outer circumferences. After assembling the inner formwork inside the tunnel hole, and placing concrete between the inner formwork and the shield tail as well as the front of the existing lining concrete, the propulsion reaction force is applied to the concrete and the inner formwork. Therefore, a tunnel construction method for propelling a shield excavator by the concrete press jack and the shield propelling jack is proposed.

(Problems to be Solved by the Invention) In the above method, since the propulsion jack and the concrete press jack are mounted on the shield excavator over two steps of the inner and outer peripheries, the working space in the excavator is narrow. In addition, a special jerk is required to support the backward pressure of the shield excavator that is generated when assembling the inner formwork and when placing concrete, and the working space becomes narrower.

The present invention has been proposed in view of the above problems of the conventional technique, and the object thereof is to ensure a wide internal working space of the shield excavator and ensure the retreat pressure of the shield excavator. An object of the present invention is to provide an improved method of constructing a tunnel which can be supported and also allows full release of the gable face of a cast lining concrete at an early age.

(Means for Solving the Problem) In order to achieve the above-mentioned object, the tunnel construction method according to the present invention is carried out by a shield excavator equipped with a shield propulsion jack and a concrete press jack along a concentric circumference. In the tunnel hole, ring-shaped steel materials are arranged at predetermined intervals along the tunnel axial direction, and an inner mold is assembled on the inner circumference of the steel material, and a plurality of the shield-propulsive jacks are attached to the ring-shaped steel material. The reaction force supporting steel material that extends in the tunnel axial direction of the small cross section of the book is penetrated, and the lining concrete is cast on the outer periphery of the inner formwork, and the cast concrete is passed through the ring-shaped steel material by the concrete press jack. And pressurize the propelling jack to propel the excavator by supporting the propelling reaction force on the reaction force supporting steel material by the propelling jack, and excavating the excavator when exchanging the jack. The reaction force supporting steel member is configured to support the backward pressure acting on the machine.

(Operation) According to the present invention, the lining concrete is lined on the outer periphery of the inner formwork assembled in the tunnel hole excavated by the shield excavator in which the shield excavation jack and the concrete press jack are mounted along the concentric circumference. While placing the concrete, the concrete is pressed from the concrete press jack through a ring-shaped steel material, and the ring-shaped steel material is used as a pressure plate and a gable form of the lining concrete part,
A reaction force is supported by a plurality of reaction force supporting steel materials having a small cross section for each propulsion jack penetrated by the ring-shaped steel material, and the shield excavator is driven by the propulsion jack. At this time, since the reaction force supporting steel material is composed of a plurality of members having a small cross section for one shield jack, the concrete flow space at the time of placing the lining concrete is secured.

Then, with the progress of excavation by the shield excavator, the reaction force supporting steel material is continued in the tunnel axial direction via the joint connecting material, and the rigidity in the tunnel axial direction is increased,
The reaction force supporting steel material is fixed to the ring-shaped steel material through the joint connecting material to support the steel material, and the function of the ring-shaped steel material as a gable formwork for the lining cast concrete part is maintained even after releasing the jack pressure. To do.

Further, the backward reaction force acting on the shield excavator at the time of assembling the inner mold and the rearrangement of the jack is supported by the reaction force supporting steel material.

(Examples) The present invention will be described below with reference to illustrated examples.

(A) is a shield excavator in which a shield propulsion jack (1) and a concrete press jack (2) are mounted in a line on a concentric circle. In the embodiment shown in FIG. 4, the two jacks (1) and (2) are alternately arranged.

Then, a tunnel hole is excavated by the shield excavator (A), and a ring-shaped steel material (4) made of, for example, H-shaped steel is formed on the inner circumference of the tail plate (3) at predetermined intervals along the tunnel axial direction. While arranging, the inner formwork (5) is assembled on the inner circumference of the steel material (4), and one propulsion jack is provided at predetermined intervals in the circumferential direction over the ring-shaped steel materials (4). A plurality of small-section reaction force supporting steel materials (6) extending in the axial direction of the tunnel are loosely penetrated in (2).

Next, a lining concrete (7) is placed between the tail plate (3) and the inner formwork (5) of the shield excavator (A) and the front side of the existing lining concrete, and the concrete press jack ( 2) is extended to press the cast concrete (7) through the ring-shaped steel material (4), the propulsion jack (2) is extended and supported by the reaction force supporting steel material (6), and the shield excavator Promote (A).

In the figure, (8) is a concrete press jack spreader.

In this manner, the propulsive reaction force of the shield excavator (A) is supported on the reaction force supporting steel material (6) in the tunnel axial direction by the shield jack (2), and the ring-shaped steel material (4) is supported by the concrete press jack (3). ) Is supported by the concrete (7), and appropriate pressure control of the concrete is prioritized, and the lacking propulsive reaction force is supplemented by the reaction force supporting steel material (6) in the axial direction of the tunnel. After the completion of the propulsion, the backward pressure after the excavation that occurs in the shield excavator when the jacking is changed is supported by the reaction force supporting steel material (6) in the axial direction of the tunnel.

The reaction force supporting steel material (6) is configured by disposing a plurality of members having a small cross section for each propulsion jack.
Fluidity of cast-in-place concrete increases.

Then, as the shield excavator (4) is propelled, the reaction force supporting steel material (6) is jointed in the tunnel axial direction by the joint connecting material (9) such as a coupler, and the rigidity in the tunnel axial direction is increased. .

After propelling the shield excavator (A), the ring-shaped steel material (4) is supported by the reaction force supporting steel material (6) through the joint connecting material (9) as shown in FIG. Even after the jack is released, the function of the cast concrete (7) of the ring-shaped steel material (6) as a gable form can be maintained, the concrete curing period becomes unnecessary, and the construction cycle time is shortened.

The retreat pressure acting on the shield excavator (A) at the time of assembling the inner formwork (5), rearranging the jack, etc., is caused by the reaction force supporting steel material (6) through the shield propulsion jack (1).
Support in.

As described above, the jack mounted on the shield excavator (A) supports the reaction reaction supporting force and the backward pressure by the reaction force supporting steel material (6) and the casting cover through the ring-shaped steel material (4). The work concrete (7) has two kinds of functions, one for supporting the reaction force of the propulsion, and the two types of the propelling jack (1) and the concrete press jack (2) are as shown in FIG. In addition to being arranged alternately, they are arranged at various ratios.

The reaction force supporting steel material needs to be a member having a sufficient cross section to support the insufficient pressure obtained by removing the concrete press pressure from the total required propulsion reaction force.

(Effects of the Invention) According to the present invention, ring-shaped steel materials extending in the tunnel circumferential direction are arranged at predetermined intervals along the tunnel axial direction on the outer periphery of the inner formwork in the tunnel hole excavated by the shield excavator. A plurality of small cross-section reaction force supporting steel materials extending in the axial direction of the tunnel are loosely penetrated per propelling jack, and a ring-shaped steel material is mounted by the concrete press jack mounted on the excavator and the outside of the inner formwork. In addition to pressurizing the lining concrete placed around the circumference, pressurizing the reaction force supporting steel material by the propelling jack, the propelling reaction force of the shield excavator is shared by both the concrete press pressure and the reaction force supporting steel material, and the shield excavator Thrust control and direction control of the shield excavator during installation of a ring-shaped steel material, assembly of an inner formwork, or concrete placing. Since it is supported by a force-supporting steel material, it is not necessary to specially provide a jack for supporting the reverse pressure of the shield excavator as in the conventional case.

Further, since the reaction force supporting steel material is composed of a plurality of members having a small cross section for each propelling jack, the fluidity of the lining cast concrete is higher than that when one large diameter member is used. Therefore, the number of times of refilling the concrete pouring mouth is reduced and the workability of concrete pouring is improved.

Further, according to the present invention, the jack mounted on the shield excavator has two functions: a concrete press jack for transmitting pressure to the cast lining concrete and a propulsion jack for transmitting pressure to the reaction force supporting steel material. Properly, for this reason the pressure control of the concrete is good, and since the concrete press jack and the propulsion jack are arranged in a line on the shield excavator in a concentric circle, as described above, Combined with the elimination of the need for the reverse pressure support jack, the work space inside the shield excavator can be increased, and workability can be improved.

[Brief description of drawings]

FIGS. 1 and 2 to 3 each show an implementation state of an embodiment of a tunnel construction method according to the present invention, and FIG. 1 shows a state of a propulsive jacking position of a tail plate-attached lining section in a shield excavator. Fig. 2 is a vertical cross-sectional view showing the state of the concrete press jack position, Fig. 3 is a vertical cross-sectional view showing the connection state of the reaction force supporting steel materials, and Fig. 4 is a propulsion in a shield excavator. It is a vertical side view showing the arrangement of the jack and the concrete press jack. (A) …… Shield excavator (1) …… Shield excavation jack (2) …… Concrete press jack (3) …… Tail plate (4) …… Ring steel (5) …… Inner form (6) ) …… Reaction force supporting steel (7) …… Concrete (9) …… Joint connection material

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 62-21989 (JP, A) JP 64-43698 (JP, A) JP 42-5785 (JP, B1)

Claims (1)

[Claims] 1. A ring-shaped steel material is arranged at predetermined intervals in a tunnel axial direction in a tunnel hole excavated by a shield excavator equipped with a shield propulsion jack and a concrete press jack along a concentric circumference. In addition, the inner formwork is assembled on the inner circumference of the steel material, and a plurality of small cross-section reaction force supporting steel materials extending in the tunnel axial direction per one of the shield propulsion jacks are loosely penetrated into the ring-shaped steel material, Placing lining concrete on the outer periphery of the formwork, pressurizing the cast concrete through the ring-shaped steel material by the concrete press jack, and supporting the reaction reaction force on the reaction force supporting steel material by the propulsion jack. Tunnel structure for propelling the excavator by means of the reaction force supporting steel material to support the retreat pressure acting on the excavator when relocating the jack. Method.