JPS6127524B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a chemical injection method.

In the general chemical injection method, before excavating a tunnel or the like, the chemical is injected into the area to be excavated to stop water, and then excavation is attempted without being hindered by spring water.

Therefore, as shown in FIG. 1, it is desirable to inject as widely as possible from the face S into the planned excavation area P.

However, as shown in Figure 2, for example, there is no need to inject the chemical into the stratum Q immediately inside the face S, while it is necessary to inject into the deeper part P'.
In some cases, it may be necessary to perform water stop treatment before the injection face reaches the inner part P'.

Furthermore, since the hydraulic conductivity of the stratum Q immediately inside the face S and the deep stratum P' are significantly different, it may be necessary to inject the chemical only into the deep stratum P' separately from other parts. Alternatively, if the area around the face is a weak stratum and the pressure of the spring water in the back is high, high-pressure injection is required into the deep stratum P′, and the injected liquid is likely to leak around the mouth or around the face. Even in such a case, it would be extremely convenient if it could be injected only into the deep stratum P'.

The present invention was developed in response to this situation, and provides a construction method that allows injection only to the deeper parts of the exposed parts of the earth, such as faces and strata, without injecting directly inside the exposed parts. The purpose is to provide.

Another object of the present invention is to provide a construction method that can perform injection into the target deep part without causing leakage to the face.

Next, an example will be described.

<1> Installation of a protection pipe (Fig. 3) To explain the case in a tunnel, a protection pipe 2 is installed at the face 1.

If face 1 is in poor condition, concrete wall 3
The collapse of face 1 may be prevented by pouring.

The protective pipe 2 is a strong pipe that is press-fitted into a hole drilled with a relatively large-diameter drilling machine.
There is no need to install it in a long section, but in a shallow section from face 1.

<2> Drilling holes (Fig. 3) Drill small-diameter holes 5 deeper than the protection pipe 2 in a long section using a small-diameter rock drill 4.

The small diameter here means that the diameter is smaller than the large diameter hole of the protection pipe 2 portion, and does not generally mean that the diameter is particularly smaller than the injection hole.

<3> Insertion of a non-metallic pipe (Fig. 4) A non-metallic pipe 6, such as a hard vinyl chloride pipe or a polyethylene pipe, is inserted into the small-diameter hole 5 after drilling.

This pipe 6 only needs to be easily destroyed as will be described later, and it is not necessary that the pipe itself can withstand the internal pressure during injection.

The tip of the non-metallic pipe 6 is the leading edge of the small diameter hole 5,
In other words, in Fig. 2, it is located in the deep stratum P'.

<4> Attaching the T-shaped pipe (FIG. 5) One end of the T-shaped pipe 7 is fixed to the outside of the protective pipe 2.

Then, one layer of the non-metallic pipe 6 is connected to the T-shaped pipe 7.
An injection material valve 8 is attached to the exposed end of the nonmetallic pipe 6, and a temporary filling material valve 9 is attached to the outlet on the orthogonal side.

The injection material here is a material that is injected at high pressure into the crack in the deep stratum P' to stop water, and stopping water is the original purpose of the injection work.

On the other hand, the temporary filling material is a material for temporarily filling the space around the non-metallic pipe 6, etc., and is only used to completely perform the original injection work.

<5> Injection of temporary filler A filler, for example, a high-strength, short-gelling-time injection material such as a high concentration suspension type water glass injection material LW, is injected at low pressure through the temporary filling material valve 9.

This temporary filling material 10 is filled into the protective pipe 2 and along the outer periphery of the nonmetallic pipe 6 towards the deep part of the small diameter hole 5, but by controlling the flow rate, it reaches around the tip of the nonmetallic pipe 6. before finishing filling.

The spring water deep in the small diameter hole 5 is drained into the tunnel through a non-metallic pipe 6 and an open injection material valve 8.

<6> Injection of injection material The earth injection material 11 is injected through the non-metallic pipe 6 whose periphery is firmly solidified with the temporary filler 10.

This injection material 11 is sufficiently injected into the crack in the stratum P' at the tip of the small diameter hole 5, but since the hole is filled with the temporary filler 10, it may return along the small diameter hole 5 or leak from the face. There's nothing to do.

<1> Excavation A tunnel will be excavated after treatment with the injection material 11, but the only injection pipe remaining underground is the non-metallic pipe 6, which can be easily destroyed, so it will not interfere with the excavation work. .

<8> Other embodiments (Fig. 6) In the above, the injection material 11 was filled after the temporary filling material 10 was filled.
Although the method of injecting has been described, there are cases where the temporary filler 10 precedes the bottom of the small diameter hole 5, such as horizontal injection or downward injection.

At that time, the ground injection material 11 with a long gel time is injected at a low speed (5 to 10/min) to prevent the tip of the non-metallic pipe 6 from clogging, and the temporary filling material 10 is
Just fill it while keeping the balance.

Since the present invention is as described above, the following effects can be expected.

<B> This is a construction method that uses the filling material that fills the injection hole and the original ground injection material that is injected into the target ground.

Therefore, even if high-pressure injection into the ground is performed, the conventional drawbacks such as leakage from the face due to the injection material returning to the direction of the face where there is less resistance can be completely prevented.

<B> Inject the ground injection material only into the desired location,
It is possible to perform processing such that injection is not performed before this point.

Therefore, the stratum in the foreground is impermeable (a stratum that does not require water-stopping treatment) and is weak, and the stratum further back is a permeable stratum that has high-pressure spring water (a stratum that requires water-stopping treatment). In certain cases, injection can be carried out only into deep geological formations.

<C> Even if the injection pipe is a non-metallic pipe, the surrounding area is hardened with filler before use, so it will not break during injection.

<D> Non-metallic pipes are cheap and easy to destroy, so there is no need to throw them away and collect them, and they do not become an obstacle when excavating the ground after treatment.

<e> Since the injection tube is disposable, ideal injection can be performed by applying sufficient pressure so that the injection tube cannot be recovered at the end of injection and minimizing the flow rate.

In the conventional method, it was not possible to perform the final injection sufficiently in consideration of recovery of the injection tube.

<F> Since it is a simple construction method similar to the single pipe rod construction method, construction is not complicated and no special construction equipment is required.

[Brief explanation of the drawing]

Figure 1: Explanatory diagram of general drug injection conditions, Figure 2
Figure: An explanatory diagram of an example of the injection method intended for this method, Figures 3 to 5: An explanatory diagram of the order of the construction method of this construction method, Figure 6: An explanatory diagram of another example, P': In the back Geological stratum, 2: protection pipe, 6: nonmetallic pipe, 10: temporary filling material, 11: injection material.

Claims (1)

[Scope of Claims] 1. A construction method in which a chemical solution is injected only into the deep strata and prevented from being injected into shallower layers, in which a non-metallic material is injected into a hole drilled to the depth where the injection is to be performed, up to the tip of the hole. A non-metallic pipe is inserted, and the gap between the hole and the pipe is filled with filler material, leaving the tip of the pipe in place. After solidification, the filler is injected from the tip of the non-metallic pipe into the ground in the deep strata. A chemical injection method characterized by injecting materials.