JPH01163398A - Method of shield excavation construction - Google Patents

Abstract

PURPOSE: To inexpensively and efficiently carry out execution of work by using a skin plate as a form and by placing concrete outside the form so as to cure the concrete up to a prescribed degree of hardness, by carrying out next excavation and by repeating the placing and curing of concrete and the excavation. CONSTITUTION: A shield is propelled by a jack, after a cutting face 4 is excavated by a cutter 11 in an excavator 1. Next, with the use of a skin plate 3 as a form, concrete pieces 5A are placed outside the skin plate 3. After the concrete pieces 5A are hardened to a certain degree of hardness, a next excavation, propulsion and placing of concrete pieces 5A are carried out, and the steps are repeated. When an enlarged width part is formed through enlarged excavation by changing the length and the angle of a boom, concrete is placed in a similar manner, and then a part of the concrete in an enlarged width part is cut.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a shield propulsion method for tunnels, and more particularly to a shield propulsion method in which the skin plate of the shield is used as a formwork for lining cast-in-place concrete.

<Background Art> For example, tunnels are used to lay power and communication cables underground in urban areas.

In addition, various maintenance experiments, such as connection work of such cables,
An enlarged tunnel section is provided that is continuous with the tunnel to allow for repairs and other maintenance. This tunnel expansion work involves enlarging and excavating a normal-diameter tunnel using the shield method, and for this purpose, the dimensions of the cutter head may be changed midway through, or a vertical shaft that is separately excavated from the ground after excavating a normal-diameter tunnel is used. We are using this to carry out expansion excavation of the planned expansion area.

<Problems to be solved by the invention> However, in the conventional shield propulsion method, in order to place cast-in-place concrete following the shield propulsion,
There were problems in that a large number of formworks had to be prepared, the transporting and connecting work of the formworks was complicated, and the workability was poor. On the other hand, when changing the dimensions of the cutter head as described above in order to perform enlarged excavation, it is necessary to temporarily suspend the excavation work, which reduces work efficiency and increases the construction period and cost. In addition, the method of using a vertical shaft not only increases the construction period and cost as described above, but is also subject to various constraints such as regional conditions such as urban areas, and above-ground and underground conditions such as the presence of underground obstacles. However, it is often difficult to implement, and it is necessary to backfill the shaft after construction, leading to problems such as an increase in layer construction costs.

This invention was made by focusing on such conventional problems, and makes it possible to perform lining of cast-in-place concrete without using formwork by using a rock excavator, and
The purpose of the present invention is to obtain a shield propulsion method that allows tunnel expansion to be carried out efficiently and at low construction cost.

Means for Solving Problems> The shield propulsion method according to the present invention uses a skin plate as a formwork, and concrete is poured outside the formwork.

<Function> The shield according to the present invention is propelled by jacks following excavation of the face with the cutter of the earth excavator, and then concrete is cast in place on the outside of the skin plate. At this time, this skin plate is used as a formwork for the poured concrete, and when the concrete has hardened to a predetermined hardness, the face is excavated again, after which the jacking is carried out and the concrete is poured. By repeating this operation, a tunnel of the planned length can be obtained. In addition, if a widened section is formed by expanding excavation by changing the length and angle of the boom, concrete is also poured into the widened section in the same manner as above, and when this concrete reaches the specified hardening, By scraping away a portion of the concrete in the widening section, an enlarged tunnel can be obtained.

<Embodiment of the Invention> An embodiment of the invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a rock excavator used to carry out the method of the present invention. In the figure, 1 is the rock excavator, which has a skin plate 3 that is propelled into a tunnel in a rock 2.

A plurality of sets of jacks 4 are attached to the inside of the skin plate 3, and a cutting edge 5 is provided at the tip of the skin plate 3. In addition, the rear end (piston rod end) of this jack 4 is connected to the concrete 5A that has already been lined.
It is supported by a gripper 6 which is firmly fixed to the inner surface. Reference numeral 7 denotes a partition wall that separates the inside of the tunnel, and 8 a power unit of the excavation machine, which is attached to the partition wall 7 and connected to an arm 9 on the face side. 10 is a boom connected to the arm 9 and operated by receiving power from the power unit 8;
It has a rotatable and extendable structure. 11 is a cutter attached to the tip of the boom 10; 12 is a mud feeding pipe that supplies muddy water on the face side, that is, between the face and the bulkhead 7;
3 is a mud drain pipe that sucks muddy water and sends it to the ground, etc., 14
is the face.

Next, in order to excavate a tunnel using the rock excavator 1 having such a configuration, the rock excavator 1 is placed in the tunnel by an arbitrary method, and the mud feeding pipe 12 is connected to the face 14 side of the partition wall 7. The power unit 8 is operated while muddy water is injected through the pump. Therefore, the power of the power unit 8 is transmitted to the boom 1 via the arm 9.
0, the cutter 11 is rotated within a predetermined area by the expansion/contraction and angle change of the boom 10 to excavate the earth. The propulsion force at this time is obtained from the jack 4, which extends while receiving a reaction force from the gripper 6. Following this promotion, cast-in-place concrete 5A is successively placed outside the skin plate 3, thereby obtaining a tunnel covered with lining concrete 5A.

In this case, after the excavation work, the skin plate 3 moves forward under the thrust of the jack 4 and stops again.
When pouring the concrete 5A in such a stopped state, this is used as a formwork. Therefore, after the concrete 5A has hardened to some extent, the above-mentioned excavation, pushing, and pouring of the concrete 5A becomes possible.

Next, when the earth excavator 1 reaches the area where the tunnel is to be expanded due to the above-mentioned propulsion, the boom 10 is greatly extended to expand its operating area. As a result, as shown in FIG.
Execute excavation. At this time, if necessary, boom 10
It may also be displaced while expanding and contracting. In this way, enlarged excavation of the tunnel into the ground 2 is performed.

When this enlarged excavation has progressed to a predetermined amount, as shown in FIG. 3, the boom 10 is first retracted, and then the jack 4 is operated to extend the piston rod. Then, the skin plate 3 moves forward so that the cutting edge 5 bites into the face 14 of the earth 2.

Therefore, a space is created between this skin plate 3 and the tunnel inner wall of the enlarged excavation section, that is, on the back side of the skin plate 3. Therefore, as shown in FIG. 3, concrete 5B drawn through a hose 16 from a concrete pouring device (not shown) is poured into this space, and the skin plate 3 is sufficiently cast as a formwork. This concrete 5
It is desirable to provide injection ports for injection of B at about six locations around the skin plate 3 so that the injection can be performed uniformly and quickly over the entire area of the excavated tunnel space.

After pouring the concrete 5B, when the concrete 5B becomes self-supporting, that is, when it reaches a hardness that does not easily collapse, the power unit 8 is activated again, Boom 1 as shown in Figure 4
0 and continue enlarged excavation. When the expansion excavation of the desired area to be expanded is completed by such an operation, a part of the tunnel becomes a thick layer of concrete 5B different from the other part as shown in FIG.

Next, in a tunnel having such a thick layer of concrete 5B, after the earth excavator 1 is moved from this part, a part of the thick layer of the concrete 5B is removed using a scraper such as a pick hammer. If this is removed, an enlarged tunnel portion consisting of a notch 16 will be obtained, as shown in FIG.

As described above, according to the method of the present invention, by using the skin plate 3 propelled by jacks as a formwork to place the concrete 5A, 5B, cast-in-place lining concrete can be cast without separately preparing formwork members. Can be installed at low cost.

In addition, in the above embodiment, the reaction force for propelling the skin plate 3 by the jack 4 was explained as being obtained from the gripper 6, but instead of this, a rock anchor driven into the ground 2, etc. may be used. .

Furthermore, the notch 16 formed by scraping off the thick layer of the concrete 5B does not necessarily have to be enlarged in concentric circles, and may have a circular cross section, a rectangular cross section, a horseshoe cross section, or other irregularly shaped cross sections. Alternatively, the cutout 15 may be provided only in a portion, for example, only on the side of the tunnel.

In addition, although the case of a muddy water shield is shown here, if the face is self-supporting, the present invention naturally includes dry excavation as it is without using muddy water.

<Effects of the Invention> As explained above, according to the present invention, the earth excavator is propelled and cast-in-place concrete is quickly poured outside the skin plate of the shield using the skin plate as a formwork. This method reduces the loosening of the ground and reduces ground surface subsidence, and requires the preparation of segment I- and special formwork compared to conventional simple cast-in-place concrete placement. This has the effect of eliminating the conventional disadvantages in terms of work and cost.

Furthermore, depending on the shape of the surrounding skin plate, tunnels with various deformed cross-sectional shapes can be constructed.

Furthermore, in the area where excavation was planned to be expanded, the length and angle of the boom of the rock excavator was changed and the cutter was used to expand the excavation, so the same tunnel excavation was continued as usual. In addition to being able to continue expanding excavation while using the earth excavator, the space behind the skin plate created after advancing the skin plate after the aforementioned expanded excavation is filled with concrete, and after the concrete hardens to a specified level, this Since the recess is formed by cutting down a part of the tunnel, the concrete structure of the tunnel expansion part can be formed in parallel with the excavation work, and an expanded tunnel can be easily and quickly obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a rock excavator used to carry out the shield propulsion method of the present invention, FIGS. 2 to 4 are explanatory diagrams for explaining the shield propulsion method of the present invention step by step,
The figure is a sectional view showing the concrete filling structure in the enlarged excavation part, and FIG. 6 is a sectional view showing the enlarged part of the tunnel made by carving out concrete. 1. Earth excavator, 3. Skin plate, 4. Jacket, 5A, 5B. Concrete, 6. Gripper.
10...Boom, 11...Cutter, 12...Sludge pipe, 1
4. Face. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Scope of Claims] 1) In a simultaneous lining shield promotion method in which a face is excavated with a ground excavator and the shield is advanced while pouring concrete, the concrete is poured while using the skin plate of the shield as a formwork. A shield propulsion method characterized by pouring. 2) In the simultaneous lining shield propulsion method in which a face is excavated with a ground excavator and the shield is propelled while pouring concrete, the concrete is poured using the skin plate of the shield as a formwork,
In the area planned for expansion, the length and angle of the boom with the cutter are changed to enlarge the face, and after advancing the skin plate, the widened part on the back side of the excavated skin plate is filled with concrete. A shield propulsion construction method characterized by forming an enlarged notch by scraping off a portion of the material after it has hardened to a predetermined value.