JPH0617573B2 - Construction method of impermeable wall - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of constructing an impermeable wall.

<< Prior Art >> As is well known, there is a slurry trench method as one of the methods for constructing an impermeable wall.

In this method, a trench-shaped drill hole is formed in the ground, and a slurry-like waterproofing filler in which clay, mortar, etc. are suspended is poured into this drilling hole to construct a relatively low-strength waterproof wall. .

Such a slurry trench construction method has an advantage that a water blocking wall can be constructed economically, but has a problem described below.

<< Problems to be Solved by the Invention >> That is, in the above-described slurry trench method, it is difficult to obtain a wall body having a higher density and higher waterproofness because the slurry waterproofing filler is simply poured into the drill hole. was there.

The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a method of constructing a water-impervious wall capable of constructing a sufficiently dense and water-stopping wall body. To provide.

<< Means for Solving the Problems >> In order to achieve the above object, the present invention forms a groove-like drilling hole in the ground, and a slurry-like stopper in which clay, mortar, etc. are suspended in the drilling hole. In a method of constructing an impermeable wall filled with a water-based filler to form a wall body, a rod-shaped or plate-shaped first electrode is erected upright along the lengthwise direction in the widthwise direction of the drilling hole, In addition, a rod-shaped second electrode is erected in the excavation hole at a predetermined distance from both ends in the width direction of the excavation hole or the first electrode, and the first electrode is connected to a DC power source. The second electrode is connected to the negative electrode of the DC power source while being connected to the positive electrode.

<< Operation >> According to the method of constructing the impermeable wall having the above-mentioned configuration, the positive electrode of the DC power source is provided on each of the first and second electrodes erected in the excavation hole into which the slurry-like waterproofing filler is poured. When connected to the negative electrode, an electric field is formed between these electrodes, and due to the electroosmotic phenomenon due to this electric field, particles such as clay and cement in the waterproof packing move to the positive electrode side, and The water inside moves to the negative electrode side.

In this case, since the first electrode on the positive electrode side is located in the center of the drill hole in the width direction, the water blocking filler is dehydrated along the length direction of the drill hole in a state where only the particle component is concentrated to a high concentration. As a result, it is possible to construct a water impermeable wall that is solidified and rich in waterproofing.

<< Examples >> Hereinafter, preferred examples of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an embodiment of a method of constructing an impermeable wall according to the present invention.

In the method of constructing the impermeable wall shown in the figure, first, the trench-shaped excavation hole 10 is formed.

The excavation of the excavation hole 10 is performed while filling the excavation hole 10 with muddy water or fresh water, and the excavation hole 10 is excavated to a predetermined depth for constructing the impermeable wall.

When the drill hole 10 is formed, clay (including bentonite), mortar, or the like is added to muddy water or fresh water in the drill hole to replace it with the slurry-like water blocking filler 12.

In this case, a slurry-like waterproofing filling material 12 having a composition adjusted in advance may be poured and replaced with muddy water or the like.

Although the above steps are the same as those of the conventional slurry trench construction method, this embodiment is characterized by the steps that will be described below.

That is, the rod-shaped first electrode 14 is supported by a suitable support material at a substantially central position in the width direction of the drill hole 10 filled with the water blocking filler 12 at predetermined intervals along the flow direction. Stand upright.

Then, a plurality of second hollow-cylindrical tubular electrodes 16 are provided upright at both ends in the width direction of the excavation hole 10 at predetermined intervals along the length direction of the excavation hole 10.

These electrodes 14 and 16 are made of a good electric conductor such as iron, copper and carbon, and have an electric resistivity of 10 ⁻⁶ to
About 10 ^-2 Ωcm is desirable.

Further, the length of each of the electrodes 14 and 16 is set to the same length as the depth of the excavation hole 10.

Then, when the first and second electrodes 14 and 16 are erected at predetermined positions, the first electrode 14 is connected in series to connect to the positive electrode of the DC power supply 18, and the second electrode 16 is connected in series. It connects and connects to the negative electrode of the DC power supply 24.

Here, the voltage of the DC power supply 18 applied between the first and second electrodes 14 and 16 is approximately 10 to 200 V, although it varies depending on the distance between the electrodes 14 and 16.

As a result, an electric field corresponding to the applied voltage is generated between the first electrode 14 and the second electrode 16, and the drill hole 10
The water blocking filler 12 therein will be present in this electric field.

When the water blocking filler 12 is present in the electric field, particles such as clay and mortar (cement) in the water blocking filler 12 move to the positive electrode side, that is, the first electrode 14 side due to the electroosmosis phenomenon, and Water in the water blocking filler 12 moves to the negative electrode side, that is, the second electrode 16 side.

The water collected on the second electrode 16 side is pumped up by connecting a water absorption pump to the electrode 16 and drained to the outside.

In this case, since the first electrode 14 on the positive electrode side is located at the center of the drill hole 10 in the width direction, only the particle component of the water blocking filler 12 is concentrated to a high concentration along the length direction of the drill hole 10. Since the water is dehydrated in the state, it is possible to construct the impermeable wall that is solidified and rich in water blocking property in a short time.

2 and 3 show another embodiment of the present invention, and only the characteristic points will be described below.

In the embodiment shown in FIG. 2, the first electrode 14 is composed of a long flat iron plate and copper plate, and the second electrode 16 is erected at the same position as in the above embodiment.

Further, in the embodiment shown in FIG. 3, the first electrode 14 is composed of a plurality of relatively short flat plates, which are linearly arranged at the center position in the width direction of the excavation hole 10 with a predetermined interval d. And the second electrode 16 is erected at the center of the space d.

If the positive and negative electrodes of the DC power supply 18 are respectively connected to the electrodes 14 and 16 thus provided upright, as in the above-described embodiment,
It is possible to construct a water-impervious wall in which only the particles are converged on the first electrode 14 side and only the particles of the water blocking filler 12 are solidified.

In addition, in these Examples, although the drill hole 10 is filled with the water blocking filler 12, the first and second electrodes 14 and 16 are erected, but the water blocking filler 12 is charged. It is also possible to previously provide the first and second electrodes 14 and 16 in advance.

In addition, when a solidifying filler such as mortar is used, it is needless to say that it is erected before it is solidified.

FIG. 4 shows an example of an experiment conducted for confirming the action and effect of the present invention.

In this experimental example, a container 20 having a thickness of 30 cm was prepared, and a clay suspension (1
5%), a copper plate was erected at the center position as the first electrode 14, and two porous iron pipes were erected as the second electrodes 16 at both ends in the width direction of the container 20.

Then, a direct current 20 is applied between the first and second electrodes 14 and 16.
A voltage of V was applied and electricity was supplied for 40 hours.

As a result, around the copper plate of the first electrode 14 on the positive electrode side,
A concentrated clay cake with a thickness of 25 cm and a water content of about 120% is formed, and its water-stopping property is 10 ^-7 to 10 in ^terms of water permeability.
It was on the order of ^-8 cm / sec.

In the above experimental example, the water collected in the second electrode 16 was allowed to naturally flow from the lower side.

<< Effects of the Invention >> As described in the above embodiments, according to the method of constructing a water-impermeable wall according to the present invention, the first and second electrodes are erected in the drill hole filled with the water blocking filler. If a positive and negative DC potential is applied to each of the electrodes, only the particles in the water blocking filler will be converged on the positive electrode side of the electrode to build a highly integrated water blocking wall with high water blocking capability. it can.

[Brief description of drawings]

FIG. 1 is a plan view showing the first embodiment of the method of the present invention, FIGS. 2 and 3 are plan views showing the second embodiment and the third embodiment, and FIG. 4 is an effect of the method. It is explanatory drawing of the example of an experiment conducted in order to confirm. 10 ... Drilling hole 12 ... Water blocking filler 14 ... First electrode 16 ... Second electrode 18 ... DC power supply

Claims (3)

[Claims] 1. A method for constructing an impermeable wall in which a trench-shaped excavation hole is formed in the ground, and the excavation hole is filled with a slurry waterproofing filler in which clay, mortar, etc. are suspended to form a wall body. In, the rod-shaped or plate-shaped first electrode is provided upright along the lengthwise direction substantially at the center in the width direction of the drilled hole, and both ends in the widthwise direction of the drilled hole or the first electrode. A rod-shaped second electrode is erected in the excavation hole at a predetermined distance from the first electrode, and the first electrode is connected to the positive electrode of the DC power source, while the second electrode is connected to the negative electrode of the DC power source. A method of constructing an impermeable wall, which is characterized by connecting with 2. The impermeable wall according to claim 1, wherein the second electrode is formed in a hollow pipe shape and also serves as a drainage pipe of the slurry-like waterproofing filling material. How to build. 3. The first electrode is formed in a plate shape and is erected at a predetermined interval in the excavation hole, and the second electrode is erected at a center position of this interval. The method for constructing an impermeable wall according to claim 1 or 2, wherein: