JPS62236993A - Method of shielding construction - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a shield construction method for performing shield excavation in order to stabilize the ground in unstable geology.

(Prior Art) In the shield method, shield excavation is stopped during segment assembly, breakdown repair of shield machinery, personnel rest, holidays, etc.

By the way, if the shield excavation stops and is left in a stopped state for a long time in ground where the geology is unstable and it is difficult to stabilize the face, especially waterlogged sandy ground, the shield excavation machine will break down, especially from the front face of the shield excavation machine. Fine earth and sand with groundwater flow into the inside of the shield tunnel, which loosens the ground above the tunnel, including the face valve in front of the shield machine, eventually leading to serious ground subsidence.

Figure 2 shows the planned direction of shield excavation shown by the imaginary line of shield excavation 4111, that is, the shield line! Section A along
Of B and C, this shows the case where construction area B has unstable ground as described above, and if the shield excavation that penetrates into construction area B is stopped and left for a long time, the above-mentioned problems will occur.

As a countermeasure against this, conventionally, a ground improvement area G is generally formed by injecting a filler from the ground in advance so as to cover the entire cross section of the shield along the entire length of the construction area B and hardening it.

(Problems to be Solved by the Invention) However, this construction method is often unprofitable as it becomes quite expensive when the distance of section B on unstable ground is long.

This invention was made in view of the above problems,
While ensuring safety when the shield tunneling machine is stopped,
The purpose is to reduce the amount of injection agent and the number of construction steps.

(Means for solving the problem) In order to achieve the above-mentioned purpose, in the shield construction method in which a shield excavator excavates into unstable ground, a method is adopted in which a shield excavator is used to dig from the inside of the shield excavator to the outer periphery at the stopping position of the shield excavator. The present invention is characterized in that an injection agent is supplied, and a solid body formed by the hardening of the injection agent surrounds the outer circumference of the shield excavator.

That is, the present invention has been made with the focus on the point that even if the ground has unstable geology, it is sufficient to suppress the outflow of groundwater that causes outflow of fine earth and sand at the stopping position of the shield excavator.

(Example) An example of the construction method of the present invention is shown in FIG. 1(a) below.

This will be explained using (b').

First, in Fig. 1, if the shield excavator 1 stops after entering the construction area B of unstable geological ground, the injection agent tank 10 prepared in the segment 2 and the pump P connected thereto The discharge ends of the discharge pipes 12 are branched and connected to a plurality of discharge pipes 12 . Each discharge pipe 12 penetrates the inner and outer peripheries of the shield tunneling machine 1 through small holes formed in the peripheral surface and front surface of the shield tunneling machine 1.

After the connection, by operating the pump P, the injection agent 11 stored in the injection agent mio is discharged to the outer circumference of the shield excavator 1 through the discharge pipe 12 at a low discharge pressure.

Then, the discharged injection agent 11 fills the gap between the shield excavator 1 and the ground. Furthermore, the pressurization allows sufficient penetration into the fine soil. Further, since the diffusion range of each of the seven discharge pipes 12 is limited, the arrangement interval of the discharge pipes 12 may be set so as to cover the entire circumference of the shield excavator 1 according to the range.

It is desirable to use a fast-curing agent as the injection agent 11, and it hardens immediately after being discharged and fills the voids etc., and as shown in FIG. 1(b), the shield excavation Ia1 is
A dense solid body G1 with excellent water-stopping properties is formed between the outer periphery of the segment 2 and the segment 2.

As described above, even if the shield excavator 1 is stopped for a long time,
Fine earth and sand do not fall into the shield excavator 1 from the front of the shield excavator 1 or the gap between the segment 2 and the shield excavator 1, and no water leakage occurs, and the condition is maintained as it is.

Note that even if the shield tunneling machine 1 is stopped due to a failure or the like, equipment for supplying the injection agent can be immediately prepared, so that it is possible to easily cope with an unexpected stoppage.

(Effects of the Invention) As explained in detail in the embodiments above, according to the construction method of the present invention, it is only necessary to supply the injection agent to the outer periphery of the shield excavator and solidify the outer periphery each time the shield excavator stops. Compared to the conventional method of injecting and hardening a filler into the entire unstable ground along the shield line, the number of man-hours and costs can be significantly reduced.

Furthermore, according to the present invention, even if the shield tunneling machine unexpectedly stops, it can be dealt with immediately and safety can be sufficiently ensured.

[Brief explanation of drawings]

Figures 1 (a) and (b) show this invention construction method, and Figure 1 (a)
) is a vertical cross-sectional view showing the state in which the injection agent is being supplied to the outer periphery of the shield tunneling machine, and (b) of the same figure shows the state in which a solid body has been formed on the outer periphery of the shield tunneling machine due to the hardening of the injection agent. FIG. 2 is a vertical cross-sectional view showing the state of injection of the injection agent in the conventional shield construction method.

Claims (1)

[Claims] (1) In the shield construction method in which a shield excavator excavates into unstable ground, an injection agent is supplied from the inside of the shield excavator to the outer periphery at the stop position of the shield excavator, and the injection agent hardens. A shield construction method characterized by surrounding the outer periphery of a shield excavator with a solid body.