JPS63107696A - Method of tunnel construction - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a method of constructing a tunnel while pouring concrete using the shield method.

[Prior Art] Recently, the number of tunnel construction projects using the shield method is increasing, and as described later, it can be roughly divided into two methods: those that use segments for the lining of shield tunnels, and those that do not.

The first method is to push the shield body into the ground, excavate the face with a cutter head, assemble the segment at the shield tail from t≧, and after completing the assembly and excavation of the segment, attach the shield propulsion jack to the segment. Propels the shield body while taking the reaction force. In this method, a tunnel is excavated in this way, and when the excavation is completed, a shield tunnel is constructed by rolling concrete lining inside the segment.

In the second method, after the shield body is advanced by a propulsion jack, a formwork is installed on the tail part of the shield body, and then concrete is poured between the tail part and the formwork. Then, the shield body is propelled using this concrete as a reaction force, and by repeating this operation, the lining concrete is directly cast without using lining segments to complete the shield tunnel.

[Problem to be Solved by the Invention J] When segments are used as the main lining material as in the first method, it is difficult to reduce costs because the segments, which are secondary products, are very expensive. In addition, two types of segments are mainly used: steel and concrete, but if concrete is poured inside the segment as a secondary lining, the inner surface of the segment will become extremely uneven, and the lining will be made of concrete due to binding etc. There are disadvantages such as the occurrence of many cracks. Furthermore, the segments expand as the temperature of the lining concrete rises, and contract as the temperature drops, resulting in concentration of stress points at the joints of the segments, which may cause cracks in the lining concrete.

On the other hand, the method of creating a shield tunnel by directly pouring concrete without using segments was inefficient because the strength of the concrete was slow to develop, reducing the shield propulsion speed. In addition, with this method, the lining concrete to be placed may become embedded in the crevices of the ground, requiring a large amount of concrete to be poured, or may wash away in front of the shield body.

Since the reaction force for shield propulsion is applied directly to the concrete lining, cracks may occur in the concrete lining if uneven pressure is applied at curves, etc.

[Object of the invention] The present invention has the following features:1. Solving the problems of the conventional technology as mentioned above,
While repeatedly reusing expensive segments without burying them, a ground hardening material or backfilling material is injected into the back of the segments connected to the rear of the shield body, and then a point where the shield propulsion reaction force is not transmitted. The purpose of this study is to propose a method for constructing a shield tunnel by directly placing concrete inside the hardened ground that is exposed after segment demolition.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a series of temporary segments at the rear of the shield body, and then injects a ground hardening material or a backfilling injection material behind the temporary segments. After injecting at least one of the above, the shield is excavated while taking a propulsive reaction force to the temporary segment, and then dismantled from the rearmost temporary segment at a point behind the shield where it is hardly affected by the propulsive reaction force, While moving the temporary segment to the front shield tail and reassembling it, lining concrete is sequentially poured inside the ground that will be exposed after dismantling the temporary segment, in other words, the ground that has been hardened with hardening material or backfilling injection material. It was designed to be set up.

To explain the present invention in more detail, a temporary segment is used to propel the shield body to maintain the earth pressure around the outer periphery of the excavation hole and at the same time function as a propulsion reaction force receiver. or harden the ground behind the segment, such as by injecting cement mortar or concrete or an equivalent hardening material or backfill injection material. Disassemble the last temporary segment using the rear geothermal heat, which is not affected by the shield propulsion reaction force, move that segment to the inside of the shield tail of the front panel, and reassemble it. The tunnel will be formed by sequentially pouring concrete lining. In this case, when the temporary segment is dismantled, the inside of the ground exposed after the dismantling is reinforced with shoring sheet piles until it is lined with 11 concrete, using a shoring device that is movable in the excavation direction. It is said that

[Example] Next, the tunnel construction method of the present invention will be specifically explained with reference to the attached drawings.

In FIG. 1, reference numeral 1 denotes a shield main body. First, the shield main body 1 is pushed into the ground by a conventional method, and after initial propulsion, a temporary segment 3 is attached to the shield tail part 2.
Assemble. Next, a backfilling material or hardening material 4 such as poorly mixed concrete, cement mortar, or cement milk is filled into the back of the temporary segment 3 assembled at the tail portion 2 through the injection pipe 4B, and the outer peripheral surface of the excavated ground is harden.

Next, the shield main body 1 is advanced while taking a reaction force to the temporary segment at the rear. In other words, the temporary segment 3 assembled on the tail part 2 of the shield body is used as a reaction force,
A shield propulsion jack 5 is directly pressed against this to obtain propulsion force. Next, the hypothetical segments 3 are reassembled into the propelled shield tail portion 2, and the ground hardening material or backfilling material is injected into the back of the segments. Then, while applying a propulsive reaction force to the connected segments,
The shield body 1 is advanced by the propulsion jack 5.

By repeating such operations, the shield is sequentially moved forward, and during this time the face is excavated with the cutter head 13 in front of the shield. The excavated earth and sand is loaded onto a loading cart 30 by an earth and sand discharge device consisting of an earth unloading screw conveyor 6, a loading belt conveyor 7, and the like, and is carried out of the mine.

On the other hand, at a rear point of the shield which is not affected by the propulsion reaction force of the shield main body, it is disassembled starting from the rearmost temporary segment 3B, and the temporary segment is moved to the front shield tail portion 2 by the transport device 8 and reassembled. The ground exposed as a result of dismantling the temporary segment 3B is self-supporting and stable with cast-in-place hardened material 4, but in order to prevent unexpected dangers such as the ground collapsing, support that can move forward in the excavation direction is required. The device 10 reinforces the hardened ground surface with the in-situ hardening material.

The structure of this shoring device will be described below. Reference numeral 21 is a main body of the shoring device, which integrally includes a shoring sheet pile 22.

The device main body 21 also has a supporting device propulsion jack 23 and a frame jack 24 (see FIG. 2). Next, the concrete lining work using this shoring @10 was carried out in step 3a.
This will be explained with reference to FIGS. 3C to 3C.

In FIG. 3a, the temporary segment 3B is dismantled at the temporary segment disassembly 1fi25 and used as a temporary segment of the front shield. At the same time as the temporary segment 3B is dismantled, the shoring sheet pile 22 of the shoring device is inserted to prevent the hardened ground from collapsing. At this time, reinforcing bars 26 and formwork 27 are being assembled at the rear of the shoring device, and the front temporary segment is dismantled while lining concrete is forced and poured from the concrete pipe 28.

Next, as shown in Fig. 31), after the lining concrete 9 is placed, the supporting device 21 is advanced by the supporting device propelling jack 23 using the formwork 27 as a reaction force receiver.

Reinforcing bars 26 are arranged at the rear where the supporting device 21 is propelled.

Subsequently, as shown in FIG. 3C, after the reinforcing bars 26 are assembled, the formwork 27 is slid or assembled. After assembling the formwork in this way and arranging reinforcing bars between it and the ground, lining concrete 9 is poured. A rich mix of concrete is used as the concrete material, and after the lining concrete has hardened, the formwork 27 is advanced and demolded.

If temporary segments are to be dismantled and removed during construction of lining concrete, the lining concrete should be placed within the permissible limits of the primary concrete while checking the stress condition of the ground.

In addition, when constructing the concrete lining, the lining work can be carried out safely by taking a method such as dismantling and removing the temporary segments one span at a time and constructing the concrete lining.

FIG. 4 shows a modification of the method of the present invention, in which an R stirring blade device 14 and a hardening material injection port 15 are provided on the outside of the cutter head portion 13, and at the same time as the shield body 1 is propelled. While injecting a hardening material such as cement milk or cement mortar from the injection port 15, the cutter head 1
This is an example in which the earth around the outer periphery of the shield is hardened by mixing it with the soil of the ground using the stirring element @14 provided in 3.

In the shield tail portion 2, a temporary segment 3 is assembled in the same manner as in the case shown in FIG. 1, and the shield main body 1 is propelled while taking a propulsive reaction force to this temporary segment.

In the example shown in FIG. 5, the stirring blade device 1 is installed outside the shield tail portion 2
6 and a hardening material injection port 17 are provided, and the hardening material is injected while stirring the ground.

[Effects of the Invention] As described in detail above, the present invention provides temporary segments that are connected to the rear of the shield main body, and then one or both of the ground hardening material and the backfill injection material is injected into the back of the temporary segments. After that, the shield is excavated while taking the propulsion reaction force into the temporary segment, and then, at the rear point of the shield where it is hardly affected by the propulsion reaction force, it is dismantled starting from the rearmost temporary segment, and the temporary segment is dismantled from the front. While moving to the shield tail part and reassembling it, lining concrete is successively placed inside the ground that has been hardened with hardening material or backfilling injection material.

According to such a method of the present invention, (1) the temporary segment is reused and is not buried, so it is extremely economical. ■When propelling the shield body, a reaction force is applied directly to the segments, so construction can be performed without problems such as insufficient reaction force during propulsion.

■Also, since the shield body can absorb the reaction force in the segments, it is easy to construct curves. (2) In the shield tail portion, the gap between the segment and the segment is filled with a ground hardening material or a backfilling injection material, so the gap between the ground and the segment is reduced, and subsidence of the ground surface is reduced. ■Concrete placed outside the segment is used only to prevent ground collapse during concrete lining construction, so the properties of concrete can be utilized to the limit. (2) Concrete, etc. placed outside the segment need only have an effect sufficient to prevent landslides.

■Even if water leaks due to cracks in the concrete placed outside the segment, water leakage can be prevented by applying pressurized air, and internal pressure is applied, making it safer. ■The segments are dismantled and lining concrete is poured in a location that will not be affected by the propulsion of the shield body, so the amount of concrete poured is small, and the concrete structure of the shield tunnel is in a healthy condition without cracks. achieved. ■Concrete lining work can be performed without being affected by shield propulsion work.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view skeletally showing a tunnel constructed by the construction method of the present invention, Fig. 2 is a side view showing the structure of the supporting device used in the present invention, Figs. 4 and 5 are partial sectional views showing modified examples of implementing the present invention. 1...Shield body, 2...Shield tail part, 3
...Temporary segment, 4...Hardening material, 5...Shield propulsion jack, 6...Earth removal screw conveyor, 7
...belt conveyor, 8...conveying device, 10...
Supporting device, 13... Cutter head section, 14.16...
- Stirring blade device, 15. 17... Inlet, 21... Supporting device main body, 22... Supporting sheet pile, 23... Supporting device propulsion jack, 24... End frame jack, 26... Rebar, 27...formwork. Applicant: Sato Kogyo Co., Ltd. Representative: Ashi 1) Direct! fji 4th
Figure 5b Shield mystery jack

Claims (1)

[Claims] 1. Temporary segments are provided in succession at the rear part of the shield body,
Next, after injecting at least one of a ground hardening material or a backfilling injection material behind the temporary segment, shield excavation is performed on the temporary segment while taking a propulsion reaction force, and then the influence of the propulsion reaction force is almost eliminated. The last temporary segment is dismantled at the rear of the shield where it will not be exposed, and while the temporary segment is moved to the front shield tail and reassembled, a concrete lining is placed on the inside of the hardened ground that is exposed after the temporary segment is dismantled. A tunnel construction method characterized by sequentially pouring. 2. A patent that uses a shoring device that is movable in the excavation direction to reinforce the inside of the hardened ground that is exposed after the temporary segment is dismantled until it is lined with concrete with shoring sheet piles. A tunnel construction method according to claim 1.