JPH0694794B2 - Tunnel construction method and apparatus - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for constructing a tunnel in which concrete cast in situ behind a shield machine is pressed and hardened, and a shield machine used for the method.

[Conventional technology]

BACKGROUND ART Conventionally, a method for constructing a tunnel lining has been developed, which accelerates hardening by pressurizing concrete cast in the rear of a shield machine to accelerate hardening. In such a tunnel lining construction method, a jack for pressuring concrete is provided separately from the propulsion jack of the shield machine, and this jack pushes the gable form that is movably arranged along the inner circumference of the shield machine to remove the concrete. Pressure is applied (see, for example, Japanese Patent Publication No. 54-33656).

[Problems to be Solved by the Invention]

 The above-mentioned conventional technique has the following problems.

A jack for pressurizing concrete is required separately from the propulsion jack, it is difficult to put both jacks in a small space, and the shield machine is extended in total length by arranging the jacks in front and back.

If you pressurize with excessive force, the reinforcing bar will be deformed.

Reinforcing bars must be left floating or attached to the gable formwork so that the reinforcing bars can move following the pressurized concrete, which requires time to assemble and deteriorates workability.

When concrete is pressed with a gable form, the position of the inner form is determined, and if the shield machine meanders, it cannot be corrected by the inner form.

If the shield machine cannot be propelled due to trouble after the concrete is placed, the concrete may be hardened, and the propellant may not be compressed even if propelled and pressurized. Therefore, if concrete is mixed so as to maintain the fluidity for a long time, the gable form cannot be removed, and the workability is greatly deteriorated.

[Means for Solving the Problems]

In the tunnel construction method according to the present invention, the shield machine is propelled and the concrete is pressurized only by the propulsion jack of the shield machine. The shield machine has a plurality of propulsion jacks on its inner peripheral surface, and a gable form which is movable in the tunnel propulsion direction is arranged corresponding to the rods of the propulsion jacks. Pull back the gable formwork with the rod of the propulsion jack, and arrange the inner formwork with the reinforcing bars attached behind the gable formwork,
Place concrete between the inner formwork and the ground. Subsequently, the propulsion jack of the shield machine is driven to press the contracting member attached to the rear side surface of each gable form in the tunnel propulsion direction against the inner form, and the shrinking member shrinks the concrete while the gland form presses the concrete. The reaction force is applied to the inner mold to advance the shield machine. In addition, a backfill material such as mortar is injected between the ground and the concrete through a backfill injection pipe which is arranged on the outer periphery of the shield machine and whose tip is open to the tail side. The lining of the tunnel is constructed by repeating the above work.

The shield machine according to the present invention is a device for use in the method for constructing a tunnel described above, and has a plurality of propulsion jacks on the inner peripheral surface of the shield machine, and each of the propulsion jacks has a corresponding one of the rods for propelling the tunnel. A gable form movable in the direction is arranged, and a contracting member is attached to a rear side surface of each gable form in the tunnel propelling direction. In addition, a backfill injection pipe with the tip opening to the tail side is arranged on the outer periphery of the shield machine, and when propelling the shield machine, a backfill material is placed between the ground and concrete from this backfill injection pipe. It is ready for injection.

[Operation] With the above configuration, by driving the propulsion jack of the shield machine, the contraction member of the end form contacts the inner form,
By compressing the contraction member and pressing the concrete placed between the gable formwork and the ground, the shield machine can be propelled by applying a reaction force to the inner formwork.

Also, at that time, the backfill material is injected into the rear of the shield machine (shield tail side) to fill the space created in the concrete and the ground, so that the waterproofness and strength of the lining can be secured Even when the shield is stopped from being propelled and the strength of the lining concrete is developed and then re-propelled, the influence on the lining concrete or the ground can be minimized by this back-filling injection.

The gable formwork that forms the ring is not integrated, and the corresponding gable formwork can be pushed out and pulled back for each propulsion jack, and the shield machine is retracted by repeatedly pulling back only some jacks. Construction can be performed without the need to do so.

〔Example〕

The present invention will be described in detail below based on an embodiment shown in the drawings.

In the figure, 1 is a shield machine, and a plurality of propulsion jacks 2 are attached to the inner peripheral surface thereof. The rod 3 of the propulsion jack 2 is extendable in the tail direction of the shield machine 1.

Corresponding to the rods 3 of each propulsion jack 2, each gable form 4
Is provided. The gable form 4 is an arc-shaped plate,
The plurality of gable forms 4 are arranged so as to form a ring shape as a whole. Further, when pushing the propelling jack 2 on one side, other jacks are made to follow the jack being pushed on one side so that the ring-shaped end form can be integrally formed, and the pouring concrete is prevented from leaking.

The wife form 4 is movable so as to move back and forth in the tunnel propulsion direction. The gable form 4 may be attached to the tip of the rod 3 to be movable, or may be movable along a rail provided on the shield machine 1.

A contracting member 5 is attached to a rear side surface of the gable form 4 in the tunnel propelling direction. The contraction member 5 is made of a material such as rubber and is attached to the center side in the width direction of the arc-shaped gable form 4 (inside the tunnel). In this embodiment, as shown in FIG. 2, the bolt 6 is attached to the mounting plate 7 of the end form 4 and a recess 8 is formed for the bolt 6 to escape when the contracting member 5 contracts. In addition, a plurality of holes 9 are formed on the outer peripheral side (ground side) in the width direction of the end form 4 to pass a reinforcing bar to be described later.

Further, a plurality of back-filling injection pipes 10 each having an end open to the tail side are arranged on the outer periphery of the shield machine 1.

Next, a method of constructing a tunnel using the above shield machine 1 will be described along with its construction procedure.

As shown in FIG. 4, after the concrete 11 that has already been cast is hardened, the end form 4 is pulled back together with the rod 3 of the propulsion jack 2. When all the propulsion jacks 2 are pulled back at once, the shield machine 1 is pushed back by the earth pressure and the concrete 11
However, since the shield machine 1 according to the present invention is provided with the end form 4 corresponding to each of the propulsion jacks 2, some of the jacks 2 are pulled back and the inner formwork described later is performed. If the jack 2 is extended again after forming 12, the shield machine 1 will not be pushed back.

Next, as shown in FIG. 5, the inner formwork 12 is assembled at the position where the end form 4 has been pulled back. The inner formwork 12 is made of steel or the like so as to take a reaction force for propulsion of the shield machine 1 and to keep earth pressure until the lining concrete 11 exhibits sufficient strength. Further, the structure is dividable so that it can be diverted, and in this embodiment, it is a box type having an arcuate cross section as shown in FIGS. 10 and 11, and the arcuate outer peripheral surface is directed toward the natural rock side. A mounting hole is formed in the arcuate outer peripheral surface, and a reinforcing bar cage 13 arranged along the outer peripheral surface is fixed by a nut 14 via a separator or the like. The inner formwork 12 is assembled by sequentially arranging the inner formwork 12 at predetermined positions by an erector and bolting.

By repeating the operations shown in FIGS. 4 and 5, the inner formwork 12 of one span is arranged. The inner formwork 12 can be removed from the mold by removing the nut 14 after the concrete 11 is hardened.
In addition, the inner formwork 12 is placed in each span, and the concrete 11
However, if the ground is stable and there is little spring water, the above operation may be repeated to pour the concrete 11 every several spans.

Subsequently, as shown in FIGS. 6 and 7, the propelling jack 2 is extended to bring the gable formwork 4 into contact with the inner formwork 12, and the fast-strength concrete 11 is brought into contact with the inner formwork 12 and the ground. Be placed in between. After the concrete pressure acting on the gable form 4 reaches a predetermined value, the pouring is finished. By driving the propelling jack 2 to press the end mold 4 against the inner mold 12, the contracting member 5 contracts and presses the concrete 11, but after contracting a certain amount, the inner mold 12 is used as a reaction force. The shield machine 1 starts propulsion so as not to apply excessive stress or deformation to the reinforcing bar.

Excess water is removed from the concrete 11 that has been pressurized to a predetermined pressure by the propulsion jack 2, and early strength is increased. Therefore, the gable form 4 can be removed relatively early, and the construction can be speeded up. Further, by disposing a reinforcing bar in a portion which is in contact with the gable form 4, it is possible to further accelerate the demolding time.

Further, with the propulsion of the shield machine 1, backfill injection is performed as shown in FIG. As the pouring material, mortar or the like having properties equal to or higher than that of the cast concrete 11 can be used. The injection pressure should always be maintained above the earth's earth pressure + water pressure. If this pressure is reduced, the adhesive force will be reduced mainly in the vicinity of the joint and the water-stopping property and strength will be reduced.

If the shield machine 1 breaks down and the propelling becomes impossible after the concrete 11 has been cast, the concrete 11 will harden before pressurizing, but even in this case, backfilling is performed in parallel during the propelling. For example, the gap between the concrete 11 and the natural ground can be filled with the backfill injection material to prevent the natural ground from collapsing.

After the completion of the predetermined propulsion, as shown in FIG. 9, curing is performed for a certain period of time, and the concrete 11 near the gable form 4 can be demolded, and then the next step is performed.

When the shield machine 1 has meandered, it is possible to fit the planned finish line by covering the inner formwork 12 with a liner or by using an atypical formwork. The lining at this time can be dealt with by making the thickness in consideration of meandering and increasing the width of the end form 4 attached to the propulsion jack 2.

〔The invention's effect〕

 This invention can obtain the following effects.

Concrete can be pressurized and propelled only by the propulsion jack, and the size of the shield machine as a whole is not large.

A contraction member is attached to the gable form, the concrete is pressed only by the amount of contraction of the contraction member, excessive stress does not act on the reinforcing bar, and the reinforcing bar is not deformed.

The gable formwork that forms the ring is not integrated, and the corresponding gable formwork can be pushed out or pulled back for each propulsion jack, so that only some jacks are pulled back and the shield machine is retracted. It can be installed without.

Since the rebars are attached to the inner formwork, the rebars can be assembled at the same time simply by assembling the inner formwork, and the construction period can be shortened.

By injecting the backfill material between the ground and the concrete through the backfill injection pipe that is arranged on the outer periphery of the shield machine and the tip opens to the tail side, it is possible to secure the waterproofness and strength of the lining. Even if the shield is stopped from propelling due to some trouble and the strength of the lining concrete has developed, and then re-propulsion, this back-filling can minimize the effect on the lining concrete or the ground. . In addition, even if it meanders, it can be easily corrected by adjusting it with a liner or the like.

[Brief description of drawings]

1 is a sectional view of a shield machine according to the present invention, FIG. 2 is an enlarged view of a II portion of FIG. 1, FIG. 3 is a perspective view of a gable form, and FIG.
Fig. 9 to Fig. 9 are sectional views of the construction sequence, Fig. 10 is a sectional view of the inner formwork, and Fig. 11 is a plan view thereof. 1 ... Shield machine, 2 ... Propulsion jack, 3 ... Rod, 4 ...
Gable form, 5 ... Shrinking member, 6 ... Bolt, 7 ... Mounting plate, 8 ...
Recess, 9 ... Hole, 10 ... Back-filling injection pipe, 11 ... Concrete, 12
… Inner formwork, 13… Reinforcing cage, 14… Nuts

Claims (2)

[Claims] 1. A gable form which is movable in a tunnel propulsion direction is provided corresponding to each rod of each propulsion jack of a shield machine having a plurality of propulsion jacks on its inner peripheral surface, and the end of said propulsion jack together with the rod of the propulsion jack. Pulling back the formwork, arranging an inner formwork with reinforcing bars attached behind the gable formwork, placing concrete between the inner formwork and the ground, and driving the propulsion jack of the shield machine to each gable form A contraction member attached to the rear side of the frame in the tunnel propulsion direction is brought into pressure contact with the inner formwork, and the contraction member contracts to press the concrete with the gable formwork, while taking a reaction force to the inner formwork to advance the shield machine. At the same time, the method for constructing a tunnel is characterized in that the backfill material is injected between the ground and the concrete by a backfill injection pipe which is arranged on the outer periphery of the shield machine and whose tip is open to the tail side. 2. A plurality of propulsion jacks are provided on the inner peripheral surface, and a gable form which is movable in the tunnel propelling direction is arranged corresponding to the rods of each of the propulsion jacks. A shield machine in which a contraction member is attached to the rear side surface in the propulsion direction, and a back-filling injection pipe whose tip opens to the tail side is arranged on the outer circumference.