JPH0583719B2 - - Google Patents

Description

[Detailed description of the invention]

[0001]

TECHNICAL FIELD The present invention relates to a press pressure holding method for continuously holding the press pressure applied to concrete after removing the pressure due to jacking via a press ring in the cast-in-place running shield method.

[0002]

[Prior Art] The cast-in-place lining shield construction method involves placing lining between the inner circumferential surface of a skin plate that constitutes the outer shell of the shield excavator and a formwork installed inside the skin plate at the same time as the shield excavator excavates. This is a construction method in which the lining is formed by high-pressure pressing of concrete, and compared to conventional construction methods, there is no need for a backfill injection process, there is no ground collapse in the tail void area, and the high-pressure pressing creates a high-strength and uniform lining. A lining structure can be obtained.

[0003] In this construction method, the advancement of the shield excavator and the high-pressure pressing of concrete are performed using a jack provided on the inner circumference of the skin plate, and the thrust is received by a press ring provided at the tip of the concrete placement surface. ing.

[0004] Therefore, the skin plate moves forward due to the reaction force of the jack, and the placed concrete is compressed through the press ring, but after that, the jack is reduced and the press pressure is removed. Then, the formwork and press ring are set again in front of it, and the concrete pouring, advancement of the shield excavator, and high-pressure pressing work are repeated again.

[0005]

[Problems to be Solved by the Invention] However, after the advance of the shield excavator for one step and the high-pressure pressing work are completed, the concrete that has been placed in the state where the pressing pressure has been removed, that is, the outer periphery of the concrete lining and the skin plate. The length of the joint with the inner circumferential surface of the skin plate is shortened by the amount that the skin plate has moved forward, and since the press pressure has been removed, there is a slight gap at the joint between the skin plate and the concrete lining. Easy to occur. If the ground is permeable and the groundwater level is high, there was a risk that groundwater could flow into the shield pit through these gaps, causing unexpected accidents and work stagnation.

[0006] This invention was made in view of the above problems, and maintains the press pressure applied to the concrete even after the pressure is removed by the press ring, thereby improving the water sealing property between the skin plate and the concrete lining. An object of the present invention is to provide a method for maintaining press pressure of a concrete lining, which can improve safety and workability when assembling formwork and press rings.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the method for maintaining press pressure of concrete lining in the cast-in-place lining shield construction method of the present invention includes forming the concrete contact surface side of the press ring to protrude in an arc shape, and , when applying pressure with the press ring, a press pressure holding plate made of an elastic body having a width wider than the gap between the skin plate and the formwork is interposed between the press ring and the tip surface of the poured concrete, and the press pressure is increased. Pressure is applied to the concrete while elastically deforming the retaining plate into an arc shape according to the shape of the press ring, and when the press ring is removed, both edges of the press pressure retaining plate are locked to the skin plate and the formwork to form an arc shape. The concrete is fixed in a curved shape to maintain the press pressure applied to the concrete.

[0008]

[Embodiment] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Figures 1a, b, and c are cross-sectional views showing the construction order of the cast-in-place lining shield construction method to which the present invention is applied.

[0009] In the figure, a shield tunneling machine 1 is provided with a plurality of jacks 3 extending rearward on the inner periphery of a cylindrical skin plate 2.

[0010] A formwork 4 having a length corresponding to the stroke length of the jack 3 is assembled into a cylindrical shape on the inner periphery of the rear part of the skin plate 2.
A press ring 5 is located between the frame 4 and the mold 4, facing the jack 3.

[0011] In this cast-in-place lining shield construction method, as shown in Figure a, concrete C is cast between the most advanced formwork 4 and the skin plate 2 through a concrete casting pipe 6.

[0012] After pouring the concrete C, the face is excavated by the shield excavator 1, and the excavated soil is discharged through the conveyors 8 and 9 provided in the shield excavator 1 and the existing shield pit 7 behind it. When the jack 3 is extended, the shield excavator 1 moves forward by the stroke of the jack 3 due to the reaction force of the jack 3, as shown in FIG.

[0013] At the same time, the concrete C is pressed under high pressure by the jack 3 through the press ring 5, filling the tail void on the rear side of the skin plate 2 and forming a high-strength and uniform concrete lining C'.

[0014] Next, as shown in Figure c, the jack 3 is reduced and the concrete lining is placed.
Skin plate 2 between C' and jack 3
By arranging reinforcing bars 10 on the inner periphery of the reinforcing bars 10, assembling a new formwork 4 inside the reinforcing bars 10, and installing a press ring 5, preparations for pouring concrete C for lining in the next step are completed.

[0015] By repeating steps a to c in the figure, the shield tunneling machine is sequentially operated.

[0016] In this embodiment, as shown in FIGS. 2 and 3, an arc-shaped protrusion 5a is formed on the contact surface side of the press ring 5 used in the above construction method against the concrete C. There is. Also, when pressurizing, press ring 5 and concrete C
A press pressure holding plate 20 is interposed between the casting tip surface and the casting tip surface.

[0017] As shown in FIG. 4, this press pressure holding plate 20 is made up of a ring plate 21 with rubber seal plates 23 attached to the front and rear surfaces of the central portion. Further, each ring plate 21 is made of a material relatively rich in toughness and elasticity, such as a thin steel plate or a thin stainless steel plate. Further, the width of the press pressure holding plate 20, ie, the width t2 of the ring plate 21, is set wider than the gap t1 between the formwork 4 and the skin plate 2.

[0018] Therefore, prior to the pressurizing process shown in FIGS.
When the press ring 5 is moved by driving the press ring 5, the press pressure holding plate 20 is curved according to the arc shape of the protrusion 5a as shown in FIG.
slip between.

[0019] In this state, pressing and digging are completed, and as shown in FIG. 3, when the press ring 5 is separated from the casting surface to release the pressing pressure by the jack 3, the retaining plate 20 remains in the curved shape and is connected to the skin plate 2. It will be clamped and fixed between the formworks 4. In other words, the retaining plate 20 retains its original width t2 due to its elastic restoring force.
trying to return to As a result, each ring plate 21, 2
The curved state is fixed by applying a force that causes the inner and outer circumferential edge portions of 2 to fit into the skin plate 2 and the formwork 4.

[0020] Therefore, after the press pressure is removed, the concrete C presses the retaining plate 20 in an attempt to be released, as shown by the arrow in FIG. 3, but the retaining plate 20 maintains its curved shape and resists this, and the concrete C This will maintain the press pressure applied to the

[0021]

[Effects of the Invention] As explained in detail in the embodiments above, according to the present invention, the press pressure applied to the concrete can be maintained even after the pressure is removed through the press ring, so the formwork and the press ring can be assembled. Sufficient water-tightness can be ensured during work, etc., and safety and workability can be improved. Also,
In this invention, since there is no loosening of the tip of concrete, the concrete lining can be made more homogeneous.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the construction sequence of the cast-in-place lining shield construction method to which the present invention is applied.

FIG. 2 is a partial cross-sectional view showing the press pressure holding method of the present invention.

FIG. 3 is a partial cross-sectional view showing the press pressure holding method of the present invention.

FIG. 4 is a perspective view showing a part of the press pressure holding plate.

[Explanation of symbols]

1...Shield excavator 2...Skin plate 3...Jyatsuki 4...Formwork 5...Press ring 5a... Arc-shaped protrusion 20...Press pressure holding plate C...Concrete C′...Concrete lining.

Claims (1)

[Claims] Claim 1. A cast-in-place lining shield construction method in which concrete placed between the skin plate of the shield excavator and the formwork is pressed at high pressure by jacks through a press ring at the same time as the shield excavator excavates. , the concrete contact surface side of the press ring is formed to protrude in an arc shape, and when press ring is pressurized, a press pressure holding plate made of an elastic body wider than the gap between the skin plate and the formwork is attached to the press ring. and the top surface of the poured concrete, pressurizes the concrete while elastically deforming the press pressure holding plate into an arc shape according to the shape of the press ring, and maintains the press pressure when the press ring is removed. A cast-in-place lining characterized in that both edges of the board are fixed in an arcuate curved shape by being locked to a skin plate and a formwork, thereby preserving the press pressure applied to the concrete. Method for maintaining press pressure of concrete lining in shield construction method.