JPH0467560B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a shoring construction method for driving a tunnel while assembling supporting members in ground with low supporting capacity, and in particular, relates to a shoring construction method in which a tunnel is propelled while assembling supporting members. This relates to a construction method that rationally prevents the collapse of support members in ground with low supporting capacity by dispersing the support members.

[Prior Art] Generally, in the construction method of constructing a tunnel by assembling shoring, the earth pressure acting on the entire surface of the covered soil must be supported by receiving plates of shoring members installed at intervals of about 1 m. Therefore, with this construction method, if the ground is hard, there is little concern that the supporting members will cave in, but when building on soft ground, there is a risk that the supporting members will cave in due to insufficient supporting force.

For this reason, a shoring method as shown in FIG. 7, for example, has been known in the past in order to disperse the earth pressure transmitted through the shoring members. This involves continuously excavating shallow grooves 10 in the longitudinal direction of the tunnel near both sides of the tunnel bottom, and filling the grooves with ready-mixed concrete 11.
This method involves laying the ground, erecting supporting steel there, and then hardening the foundation with concrete 11.

[Problems to be solved by the invention] However, the above construction method requires the work of excavating a trench at the bottom of the tunnel, and since it takes time for the concrete poured into the trench to harden, it is difficult to continuously stand the supporting members. The construction was difficult, and the tunnel propulsion work could not be carried out smoothly. In addition, when ultimately excavating a tunnel with a horseshoe-shaped cross section, the tunnel with a semicircular cross section as shown in Figure 7 is excavated forward, and then the lower tunnel is excavated backwards, so the concrete must be destroyed and removed. However, the work was not easy and it was impossible to quickly advance the tunnel.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a shoring method that eliminates the drawbacks of the above-mentioned prior art, rationally prevents the support members from collapsing, enables work in a narrow space, and allows rapid tunnel propulsion work. It is something to do.

[Means for Solving the Problems] In order to achieve the above object, the structure of the present invention will be explained. The present invention has the following features: a tunnel is excavated, and a support member is installed on the bottom of the tunnel in the longitudinal direction of the tunnel. Holes are sequentially drilled slightly laterally at appropriate intervals, the drilled holes are filled with injection material, reinforcing material is inserted, a support plate is laid over the hole, and the support plate is used as the base. Support members are erected. Further, this support plate may be provided with appropriate holes. This makes it easier to increase the number of hits when the ground subsides.

[Actions and Effects of the Invention] The present invention achieves the following effects by the means described above.

Drilling holes in the tunnel bottom one after another is easier than the conventional process of digging a continuous trench and pouring concrete.

The injection material injected between the hole and the reinforcing material hardens quickly.

The ground will be further strengthened by inserting reinforcing materials.

When excavating a tunnel backwards to the lower part of the tunnel, there is no need to remove reinforcing material or injection material, making subsequent work easier than with conventional construction methods.

If the core is left in order to make the face self-supporting, the work space for erecting the support will become narrower, but even in such a case the work can be done without any restrictions.

When excavating the lower part of a tunnel, the remaining reinforcing material acts as an earth retainer on the side, allowing work to be carried out safely.

If the amount of settlement is expected to be large, reinforcement can be performed by using a perforated plate.

[Example] Hereinafter, an example of the present invention will be described based on the drawings.

1 to 5 show step by step an embodiment of the shoring method of the present invention, and FIG. 6 is an enlarged view of the main part of FIG. 4.

FIG. 1 is a longitudinal cross-sectional view showing a situation in which a tunnel with a semicircular cross section is to be excavated in a rock mass with a small supporting capacity. Because the rock is soft, there is no need to carry out any work such as blasting, and excavation can be carried out by hand or a power shovel, but the face is difficult to stand on its own.
For example, a presser such as the nuclear remnant 12 is required. In addition, sufficient shoring is required, so it is necessary to strengthen the ground as shown below.

FIG. 2 is a longitudinal cross-sectional view showing a state in which holes are being sequentially drilled in the tunnel bottom surface in the longitudinal direction of the tunnel by the drilling machine 7. The diameter, depth, and spacing of the hole 1 are determined by the size and position of the supporting member 5, which is selected according to the scale of the tunnel and the strength of the ground. For example, the diameter of the hole 1 is 60 mm, and the depth is 60 mm. It is about 1500mm. It is preferable that the hole 1 is formed obliquely outward (for example, at an angle of about 15 degrees) as shown in FIG. 4b.

FIG. 3 is a longitudinal sectional view showing a state in which a pouring material 3 such as mortar is injected into the hole 1, a reinforcing material 2 is inserted into the hole 1, a support plate 4 is laid, and a shoring 5 is erected. It is. The reinforcing material 2 is a reinforcing bar, and the injection material 3 is a mixture of concrete, resin, etc. in addition to mortar. Additionally, if the amount of settlement of the shoring is expected to be large, use a support plate with holes.

FIG. 4a is a vertical cross-sectional view showing the progress of this work, with the support plate 4 as a base and an arch-shaped support member 5 erected thereon, and FIG. 4b is a cross-sectional view thereof. be. In this embodiment, the holes 1 are provided in two rows in the longitudinal direction of the tunnel. Since the ground under the support plate 4 is reinforced by the reinforcing material 2 and the injection material 3, there is no fear that the support member 5 will cave in, and the support member 5 is erected in a stable state, so that the area around the tunnel is Earth pressure is reasonably distributed. This state is shown enlarged in FIG.

FIG. 5a is a longitudinal cross-sectional view showing a state in which a tunnel with a semicircular cross section is advanced and then the tunnel is advanced and propelled at the bottom so that the cross section finally becomes a horseshoe shape. Figure b is its cross-sectional view. When excavating a tunnel for backward movement, since a plurality of holes 1a are further drilled diagonally outward, there is no need to remove the reinforcing material 2 when excavating a tunnel for backward movement. In addition, the remaining reinforcing material 2 plays the role of retaining earth during excavation of the lower part, making the excavation work safer. The ground reinforcement method for the backward tunnel may be the same as the above method.

[Effects of the Invention] As explained above, according to the present invention, the following effects can be achieved.

The work of sequentially digging holes in the bottom of a tunnel is easier and requires less labor than the conventional work of digging continuous trenches.

Because the injection material only needs to be injected between the hole and the reinforcing material, it hardens more quickly than with conventional construction methods, allowing for quick work to proceed to the next step.

As for ground reinforcement, the presence of reinforcing materials makes it possible to form a strong ground, and as a result, the support plate can be made smaller, making it easier to work around the area.

There is no need to remove reinforcing materials or injection materials, and there is no need for conventional work such as destroying the entire area of concrete within the trench.

Therefore, tunnel excavation work can be carried out more quickly than with conventional methods.

When excavating the lower part of a tunnel, the reinforcing material left behind acts as a side earth retainer, increasing the safety of the lower part of the tunnel.

If the amount of subsidence is expected to increase, additional strikes can be applied, making reinforcement possible.

Overall cost is lower.

As described above, according to the present invention, it is possible to shorten the construction period, make the work easier and safer, and moreover, it is possible to perform stable shoring safely.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the first step of the present invention, FIG. 2 is a longitudinal sectional view showing the second step of the invention, FIG. 3 is a longitudinal sectional view showing the third step of the invention, and FIG. Figure a is a vertical sectional view showing the fourth step of the present invention, Figure 4 b is a cross sectional view thereof, Figure 5 a is a vertical sectional view showing the fifth step of the present invention, and Figure 5 b is a cross sectional view thereof. FIG. 6 is an enlarged view showing the state in which the shoring structure is erected according to the present invention.
FIG. 7 is an explanatory diagram of the prior art. 1... hole, 2... reinforcing material, 3... injection material, 4...
...Support plate, 5...Support member.

Claims (1)

[Claims] 1. Excavate a tunnel, then drill holes in the longitudinal direction of the tunnel at appropriate intervals near where the supporting members will be erected on the bottom of the tunnel, fill the dug holes with injection material, and then insert reinforcing materials. , a shoring construction method characterized by laying a support plate above the hole and erecting a support member using the support plate as a base.