JPH0686799B2 - Construction method for cast-in-place lining shield and pressurizing device therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is to construct a reinforced concrete lining by arranging rebar on a tunnel shaft excavated in the ground by a shield machine and placing fresh concrete. It is related to the cast-in-place lining shield construction method.
It is intended to provide a tunnel structure having stress-bearing materials continuously arranged in the tunnel axis direction and having sufficient safety even under bad ground conditions such as landfill.

[Conventional technology]

Conventionally, the shield tunnel lining was constructed using steel or reinforced concrete segments, but it has the disadvantages of high segment manufacturing costs and time-consuming segment assembly and backfill injection work. It was
From such a point of view, recently, a cast-in-place lining shield construction method has been proposed which uses cast-in-place reinforced concrete as an alternative to the segment to reduce the construction cost and shorten the construction period.

[Problems to be solved by the invention]

In the above-mentioned cast-in-place lining shield construction method, the tail void generated in the tail portion of the shield machine is surely filled with fresh concrete, and
In order to ensure the quality of the lining concrete, the fresh concrete immediately after being placed is pressed, so it is an important issue whether or not the reinforcing bar is arranged at a predetermined position. Therefore, for example, JP-A-63-1
There are techniques such as those disclosed in 4997 or Japanese Patent Laid-Open No. 63-147096. However, in the former case, the assembled rebar moves to the rear of the shield tunnel together with the concrete under pressure, so a sufficient joint length cannot be obtained for the axial rebar of the tunnel and that of the existing axial rebar of the tunnel. There was a problem that it was difficult to construct a reliable joint because concrete adhered to the joint. Further, in the latter case, there is a problem that the thickness of the pressure plate must be increased in order to obtain a sufficient joint length for the axial reinforcing bar in the tunnel. The present invention has been made in view of the above problems,
The purpose is to prevent concrete from adhering to the joints of the reinforcing rods in the axial direction of the tunnel, and by ensuring a sufficient joint length, a stress-bearing material that is continuous in the axial direction of the tunnel is arranged for high safety. To provide a tunnel structure.

[Means for solving problems]

According to the present invention, a pressure plate provided at the rear end of a press jack and having a predetermined number of reinforcing bar insertion holes, a seal member disposed on the inner circumference of the pressing plate and made of an elastic member, and a reinforcing bar insertion of the pressing plate. A conical hollow waterproof body formed so that one end can be inserted into the hole and the other end cannot be inserted, and an outer diameter that allows close insertion into the hollow portion of the hollow waterproof body, By using a pressurizing device in combination with a sleeve pipe that can be inserted and whose one end is closed, a fixed length portion on the face side is covered with a sleeve pipe fitted with a hollow water blocking body, and the open end of the sleeve pipe is covered. The tunnel axial rebar sealed with a waterproof sealing material is installed at a predetermined position of the concrete placing planned part together with the tunnel circumferential main rebar and the inner formwork, and the tunnel axial rebar projects from the existing concrete part. tunnel After successfully bonded to the direction reinforcing bars,
The pressing plate is installed at a predetermined position while penetrating all the tunnel axial direction reinforcing bars into the reinforcing bar insertion holes of the pressing plate,
Tail portion of the shield machine, placing fresh concrete in the space formed by the inner formwork and the concrete portion, press the fresh concrete with a press jack via a pressure plate, after the pressurization the cleave pipe and The problem was solved by removing the hollow water stop body and constructing a tunnel lining.

[Action]

In the present invention, a fixed length portion on the face of the tunnel axial direction rebar to be arranged in a concrete pouring planned portion is covered with a sleeve pipe and slid into a rebar insertion hole provided in a pressure plate through a hollow water blocking body. Since it has a structure that allows it to move freely and has water stopping property, it is possible to join the tunnel axial reinforcing bars continuously while ensuring a predetermined lap length without concrete adhering to the tunnel axial reinforcing bars. Can be done.
Moreover, since the opening / closing opening provided in the inner formwork can be used to securely join the tunnel axial direction rebar with the tunnel axial direction rebar protruding from the existing concrete part, it was temporarily fixed to the inner formwork. A strong rebar cage can be formed by combining with the main rebar in the circumferential direction, and the rebar cage can be securely installed at a predetermined position without moving even when placing and pressing fresh concrete.

〔Example〕

A pressurizing plate 3 provided at the rear end of the press jack 1 and having a reinforcing bar insertion hole 2, a resilient shield tail seal member 4 provided at the inner circumference of the pressing plate 3, and a close insertion hole for the reinforcing bar inserting hole 2. 2 fits the sleeve pipe 6 having a diameter that can be closely inserted into 2 and having one end closed, and the tapered hole-shaped portion 7 formed to have a larger diameter than the front portion by cutting the rear end portion of the reinforcing-bar insertion hole 2 in a tapered shape. The pressure device A is formed by combining the hollow rubber cone 8 having a substantially conical shape. Next, an example of the construction sequence will be described. A tunnel circumferential main rebar 10 temporarily fixed to the inner formwork 9 through the inner formwork 9 and an assembling jig at a predetermined position of a concrete pouring planned portion. While assembling, a fixed length part of the end face of the tunnel axial direction reinforcing bar 11 is covered with the sleeve pipe 6, the hollow rubber cone 8 is fitted into the sleeve pipe 6, and the open end 6a of the sleeve pipe 6 is stopped. After sealing with the water-based sealing material 19, the tunnel axial reinforcing bar 11 is assembled and installed at a predetermined position. Then
The opening / closing opening provided in the inner frame 9 is used to continuously join the tunnel axial reinforcing bar 11 to the tunnel axial reinforcing bar 11a protruding from the existing concrete portion 14 with a required overlapping length. Thereafter, the press jacks 1 are extended to allow all the sleeve pipes 6 to penetrate through the reinforcing bar insertion holes 2 of the pressure plate 3, while the hollow rubber cones 8 are loosely pushed into the tapered hole-shaped portions 7 of the reinforcing bar insertion holes 2 to press the pressing plate 3 in a predetermined manner. Set to the position. Fresh concrete 16 is placed in a space 15 formed by the pressure plate 3, the shield tail 13, the inner formwork 9 and the existing concrete 14, and the press jack 1 is extended to press the fresh concrete 16. At this time, when the press jack 1 is extended and the fresh concrete 16 is pressed, the hollow rubber cone 8 is strongly pressed into the tapered hole portion 7 of the reinforcing bar insertion hole 2 to prevent mortar leakage. The shield machine 18 extends the shield jack 17 to
To move forward as a reaction force. After the pressurization for a predetermined time is completed, the pressurizing plate 3 is pulled back to the face of the face and the sleeve pipe 6 and the hollow rubber cone 8 are removed. The cast-in-place lining shield is completed by repeating the above steps. In addition, the sleeve pipe 6 fitted with the hollow rubber cone 8 is previously fitted to the tunnel axial direction reinforcing bar 11, the reinforcing bar cage is formed together with the tunnel circumferential direction main reinforcing bar 10 and temporarily fixed to the inner formwork 9. You can leave it.

〔effect〕

According to the method and apparatus for constructing a cast-in-place lining shield of the present invention, it is possible to reliably and continuously join the reinforcing bars in the axial direction of the tunnel and prevent concrete from adhering to the joint portion. Further, since the rebar cage does not move even during the concrete pouring / pressurizing work, the rebar can be arranged at a predetermined position of the tunnel lining. Therefore, it is possible to provide a tunnel structure by the cast-in-place lining shield method, which has sufficient safety even under poor ground conditions such as landfill ground, which was conventionally considered difficult to construct.

[Brief description of drawings]

Fig. 1 is a schematic drawing of the construction of cast-in-place lining shield, Fig. 2 is a sectional view of the completed tunnel, Fig. 3 is a detailed view of the concrete joint, Fig. 4 is a front view of the pressure plate, and Fig. 5 is the pressure plate. Fig. 6 is a detailed view of Fig. 6 is a perspective view of a hollow rubber cone, Fig. 7
abcde is an explanatory diagram of the construction order.

Claims (4)

[Claims] 1. In a cast-in-place lining shield construction method in which a tunnel wall formed by a shield excavator is lined with cast-in-place reinforced concrete, a fixed length portion on the face of the face is covered with a sleeve pipe fitted with a hollow rubber cone. The tunnel axial rebar with the open end of the sleeve pipe sealed with a waterproofing sealant is installed at a predetermined position in the concrete placing planned part together with the tunnel circumferential main rebar and the inner formwork, and the tunnel axial rebar is installed on the existing concrete. After continuously joining the tunnel axial direction reinforcing bars protruding from the portion, the pressing plate is installed at a predetermined position while penetrating all the tunnel axial direction reinforcing bars into the reinforcing bar insertion holes of the pressing plate, and the pressing plate and the shield are installed. Place fresh concrete in the space formed by the tail part, inner formwork and concrete part of the machine. Construction method of cast-in-place lining shield, characterized in that to construct the fresh concrete was pressurized by a press jack via the pressure plate, and removed the sleeve pipe and the hollow Gomukon after completion pressure tunnel lining. 2. A press plate provided at the rear end of the press jack and having a predetermined number of reinforcing bar insertion holes, a seal member disposed on the inner circumference of the press plate and made of an elastic member, and the press plate. A conical hollow rubber cone formed so that one end can be inserted into the rebar insertion hole and the other end cannot be inserted, and an outer diameter that allows close insertion into the hollow portion of the hollow rubber cone, A pressurizing device for a cast-in-place lining shield, which is combined with a sleeve pipe which can be inserted and whose one end is closed. 3. In a cast-in-place lining shield construction method in which a tunnel wall formed by a shield excavator is lined with cast-in-place reinforced concrete, a fixed length portion on the face of the face is covered with a sleeve pipe through which a hollow water blocking body is inserted. The tunnel axial rebar with the open end of the sleeve pipe sealed with a waterproofing sealant is installed at a predetermined position in the concrete placing planned part together with the tunnel circumferential main rebar and the inner formwork, and the tunnel axial rebar is installed on the existing concrete. After continuously joining the tunnel axial direction reinforcing bars protruding from the portion, the pressing plate is installed at a predetermined position while penetrating all the tunnel axial direction reinforcing bars into the reinforcing bar insertion holes of the pressing plate, and the pressing plate and the shield are installed. Placing fresh concrete in the space formed by the tail part of the machine, the inner formwork and the concrete part, Construction method of cast-in-place lining shield, characterized in that pressurizes the threshold concrete by press jack via the pressure plate, and removed the sleeve pipe and the hollow water stop body after completion pressure build a tunnel lining. 4. A press plate provided at the rear end of the press jack and having a predetermined number of reinforcing bar insertion holes, a seal member arranged on the inner periphery of the press plate and made of an elastic member, and the press plate. A conical hollow water blocking body formed so that one end can be inserted into the rebar insertion hole and the other end cannot be inserted, and an outer diameter that allows close insertion into the hollow portion of the hollow water blocking body, A pressurizing device for a cast-in-place lining shield, which is characterized by being combined with a sleeve pipe capable of being interpolated and having one end closed.