JP3324012B2 - How to build an artificial water-impermeable layer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing an artificial water-impermeable layer using a water-permeable layer.

[0002]

2. Description of the Related Art In a conventional digging work or the like, digging is performed by making a digging wall penetrate into a hardly permeable layer underground to reduce the infiltration of groundwater. However, when the soft permeable layer does not exist at an appropriate depth, a number of borings are carried out from the ground inside the retaining wall, and a chemical solution is injected therefrom to construct an artificially permeable layer.

[0003]

Problems to be Solved by the Invention The above-mentioned conventional method for constructing an artificial water-impermeable layer has the following problems.

<A> As the excavated surface becomes wider, the number of drilling holes for chemical injection increases, and much time and cost are required for the operation.

<B> When the water-impermeable layer is formed at a large depth, the boring length per one becomes long, and it takes a lot of time and cost to construct the water-impermeable layer.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a method for constructing an artificial water-impermeable layer which can quickly and economically construct a water-impermeable layer. To provide.

[0007]

According to the present invention, a retaining wall is constructed at a depth reaching a permeable layer, and an injection pipe having a length reaching the permeable layer penetrates along the retaining wall. At the same time, at a position distant from the injection pipe, penetrate a recovery pipe of a length reaching the permeable layer, while discharging the chemical solution from the injection pipe to the permeable layer,
A method for constructing an artificial water-impermeable layer, characterized in that a suction is performed by a recovery pipe to penetrate a chemical solution, and a water-permeable layer in which the injection pipe and the recovery pipe are located is formed as a poor water-permeable layer.

[0008]

Embodiment 1 An embodiment of the present invention will be described below with reference to the drawings.

<A> Construction of the retaining wall (FIG. 1) The retaining wall 1 is constructed by a known method surrounding the area to be excavated. In this case, the lower part of the retaining wall 1 is made to penetrate into a permeable layer 4 having excellent water permeability such as a gravel layer.

<B> Installation of Chemical Injection Pipe (FIG. 1) The chemical injection pipe 2 penetrates the ground 5 to be excavated near the retaining wall 1. The chemical injection pipe 2 is a tube having a length reaching the permeable layer 4 and having a discharge hole 21 for discharging a chemical liquid at a lower part thereof, and an upper part connected to the discharge pump P1 to supply the chemical liquid 6 in the tank. The liquid can be discharged in the permeable layer 4.

<C> Installation of chemical recovery pipe (FIG. 1) The chemical recovery pipe 3 penetrates into the ground 5 to be excavated away from the retaining wall 1. The collection pipe 3 is provided with a water permeable layer 4 like the injection pipe 2.
, And the upper part thereof is a suction pump P
2 is connected. The operation of penetrating the injection pipe 2 and the recovery pipe 3 may be performed in parallel.

<D> Construction of an artificially impervious water-permeable layer (FIGS. 1, 2,
3) The operation of both pumps P1 and P2 is started, and the chemical solution 6 is discharged from the tip of the injection pipe 2 into the permeable layer 4. Simply discharging the chemical solution 6 from the injection pipe 2 limits the permeation range of the chemical solution 6. In the present embodiment, since the negative pressure is suctioned by the recovery pipe 3 provided at a position distant from the discharge position of the chemical liquid 6, the chemical liquid 6 discharged from the injection pipe 2 moves in the water-permeable layer 4 toward the recovery pipe 3. Then, a part of the chemical solution 6 is collected by the collection pipe 3 together with the groundwater. As a result, the water-permeable layer 4 located between the injection pipe 2 and the recovery pipe 3 is formed as a continuous artificial water-impermeable layer 7. still,
When the depth to the permeable layer 4 is large, the pump is
In some cases, suction may be provided at the lower end of the head.

<E> Excavation (FIG. 3) The artificially impervious layer 7 closes the bottom of the retaining wall 1 to prevent groundwater outside the retaining wall 1 from entering the inside of the retaining wall 1. Block. As a result, the retaining wall 1
Excavation can be carried out.

[0014]

[Embodiment 2] When constructing a retaining wall, a chemical injection pipe may be attached in advance to a reinforcing steel cage, a steel pipe sheet pile or the like of a continuous underground wall, which is one of the constituent members of the retaining wall. In this embodiment, it is not necessary to penetrate an independent injection tube, so that the operation can be simplified.

[0015]

[Embodiment 3] When the installation distance between the chemical injection pipe 2 and the chemical recovery pipe 3 is large, the permeable layer 4 is placed between the injection pipe 2 and the recovery pipe 3.
An auxiliary pipe (not shown) having a length to reach
The discharged chemical solution 6 is sucked by the auxiliary pipe, and firstly the chemical liquid 6 penetrates into the permeable layer 4 between the injection pipe 2 and the auxiliary pipe. Next, when the chemical solution 6 is discharged through the auxiliary pipe, the chemical liquid 6 is sucked by the recovery pipe 3, and the chemical liquid 6 penetrates into the permeable layer 4 between the auxiliary pipe and the recovery pipe 3. By performing the above operation, a poorly permeable layer can be easily constructed even when the installation distance between the chemical injection pipe 2 and the chemical recovery pipe 3 is large.

[0016]

As described above, the present invention has the following effects.

<A> In the method for constructing an artificial water-impermeable layer according to the present invention, since the amount of boring used when constructing the artificial water-impermeable layer is reduced, the work of constructing the water-impermeable layer is quickened and the cost is greatly increased. Can be reduced.

<B> The method for constructing an artificially impervious layer according to the present invention can be applied to work on site having a deep and wide excavation part.
Since less boring is used, the construction work of the impervious layer can be accelerated and the cost can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an artificial water-impermeable layer according to the present invention before construction.

FIG. 2 is a cross-sectional view of the construction of the artificially impervious layer.

FIG. 3 is an explanatory view at the time of excavation.

Continuation of the front page (56) References JP-A-61-60919 (JP, A) JP-A-49-111411 (JP, A) JP-B-35-7425 (JP, B1) (58) Fields investigated (Int .Cl. ⁷ , DB name) E02D 3/12 101 E02D 19/12 E02D 31/02

Claims (1)

(57) [Claims] 1. A ridge wall is constructed at a depth reaching a permeable layer, and an injection pipe having a length reaching the permeable layer penetrates along the ridge wall and at a position away from the injection pipe. Into the permeable layer through the collecting pipe, and while discharging the chemical solution from the injection pipe to the permeable layer, sucking the recovery pipe to penetrate the chemical solution, Forming an artificial water-impermeable layer, wherein the layer is formed as a water-impermeable layer.