JPH06257134A - Method for improving soft ground - Google Patents

Abstract

PURPOSE:To solidify the ground all over a wide range. CONSTITUTION:A first pipe 1 formed with multiple drilled holes is inserted into the ground, and plural second pipes 10 respectively formed with multiple drilled holes are inserted into the ground along a first circle 9 around of the first pipe 1 with a nearly equal space. Under the condition that the first pipe 1 is made to function as a positive electrode and the second pipes 10 are made to function as a negative electrode and the direct current voltage is applied between the first pipe 1 and the second pipes 10, the first pipe 1 is filled with the mixture liquid of sodium silicate and calcium chloride to solidify the ground all over a range of the first circle 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for improving soft ground, which is used for constructing a building and, if the land is soft ground, improving the land to hard ground without replacing the soil.

[0002]

2. Description of the Related Art When constructing a building, if the land is soft ground, it is necessary to improve the land to hard ground.

As an example of a conventional method for improving such soft ground, Japanese Patent No. 1534576 (Japanese Patent Publication No. 1-18208) invented by the present inventor.
There is a method of improving soft ground. In this method, a large-diameter outer pipe with a large number of holes is driven into the ground to be improved, then an inner pipe with a large number of holes is driven into the center of the outer pipe, and then these outer pipes are driven. A direct current voltage is applied between the inner tube and the inner tube, and the chemical solution is injected into the phenomenon portion in the electroosmosis phenomenon caused by the application of the direct current voltage, and the reaction is performed to solidify the ground to be improved.

[0004]

However, this method is
The range where the ground can be solidified in one operation is the narrow part inside the outer pipe, so when improving the soft ground in a wide area, the outer pipe and the inner pipe must be improved over a very large number of times. It had to be driven into the ground, which required a great deal of effort.

Further, it is necessary to prepare two types of pipes, an outer pipe having a large diameter and an inner pipe, and in particular, since the outer pipe having a large diameter has a large volume, it is difficult to transport it to the construction site.

An object of the present invention is to provide a method for improving soft ground, which is capable of remedying the above-mentioned conventional drawbacks and solidifying a wide range of ground very easily.

[0007]

According to the method for improving soft ground of the present invention, a first pipe having a large number of holes is inserted into the ground, and a plurality of second pipes having a large number of holes are formed. Are inserted into the ground at substantially equal intervals along a first circle having the first tube as a center of gravity, and the first tube serves as an anode and the second tube serves as a cathode. The method is characterized in that a mixed solution of sodium silicate and calcium chloride is injected into the first tube while a direct current voltage is applied between the first tube and the second tube, and a large number of holes are formed. The first pipe is inserted into the ground, and a plurality of second pipes having a large number of holes are formed in the ground at substantially equal intervals along a first circle whose center is the first pipe. The first tube is inserted into the first tube and the second tube is used as a cathode, and a DC voltage is applied between the first tube and the second tube. A second circle having a radius larger than that of the first circle having a plurality of third tubes, into which a mixed solution of lithium and calcium chloride is injected, and then a plurality of holes are formed Insert into the ground at approximately equal intervals along the
With the third tube as an anode and a DC voltage applied between the second tube and the third tube, a mixed solution of sodium silicate and calcium chloride is applied to the second tube. It is also characterized by injecting.

[0008]

According to the invention of claim 1, the ground in the area surrounded by the first circle is solidified by the application of the DC voltage and the injection of the mixed solution.

According to the second aspect of the present invention, the ground in the area surrounded by the first circle is solidified by the first application of the DC voltage and the injection of the mixed solution, and the second DC voltage is applied and the injection of the mixed solution is performed. The ground in the area surrounded by the second circle and the first circle solidifies.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view showing a state in which a pipe is inserted into the ground according to the invention of claim 1, and FIG. 2 is a sectional view taken along the line II-II of FIG. 1 for carrying out the invention of claim 1. First, the first pipe 1 is inserted into the ground by selecting the vicinity of the center of the soft ground to be improved and hardened.

The first tube 1 is composed of one upper tube 2, an appropriate number of middle tubes 3 and one lower tube 4 as shown in the enlarged vertical sectional view of FIG. .

It is convenient to use steel gas pipes each having an outer diameter of about 60 mm for the upper pipe 2, the middle pipe 3, and the lower pipe 4, and a large number of holes are provided around the middle pipe 3 and the lower pipe 4. 5, the upper pipe 2 and the middle pipe 3 are engraved with male threads 6 at the lower ends, and the upper ends of the middle pipe 3 and the lower pipe 4 are engraved with female screws 7 with which the male screws 6 can be screwed. Further, a drilling blade 8 is fixed to the lower end of the lower pipe 4.

The male screw 6 of the upper pipe 2 and the middle pipe 3 as described above
2 are sequentially screwed into the male threads 6 of the middle pipe 3 and the lower pipe 4, so that one upper pipe 2, a proper number of middle pipes 3 and one lower pipe 4 are connected as shown in FIG. Combined, the first tube 1
Make up. The length of the first pipe 1 is selected such that the number of the middle pipes 3 to be joined is approximately the same as the depth of the soft ground to be improved and hardened.

When inserting the first pipe 1 into the ground, a small and lightweight boring machine conventionally used for soil investigation is installed near the center of the soft ground selected as described above. The first pipe 1 is rotated to reach a predetermined depth while drilling the soft ground by the excavating blade 8 at the lower end of the lower pipe 4.

After inserting the first tube 1 into the ground in this way, assume a first circle 9 having the first tube 1 as the center of gravity, as shown in FIG. The radius of the first circle 9 is set to an appropriate size of about 0.8 to 1 meter according to the permeability coefficient of the ground, and the radius of the first circle 9 is set to be approximately equal to the radius. Insert the second tube 10 into the ground. Second tube 1
0 is also a combination of one upper pipe 2, an appropriate number of middle pipes 3 and one lower pipe 4, just like the first pipe 1, and the circumference of the middle pipe 3 and the lower pipe 4. Since a large number of holes 5 are formed in the hole, the same operation is repeated for the work of inserting it into the ground.

After inserting the first pipe 1 and the second pipe 10 into the ground as shown in FIGS. 1 and 2, the central first pipe 1 is connected to the anode of the DC power source. Then, all the surrounding second tubes 10 are connected to the cathode of the DC power supply, and a low DC voltage of about 15 to 25 volts is applied between the first tube 1 and the second tube 10. . Then, while continuously applying the DC voltage, a mixed solution of sodium silicate and calcium chloride is injected into the central first tube 1 from the upper end. When injecting the mixed liquid into the first pipe 1 from the upper end, the utility model registration No. 1858484 (Jpn.
It is preferable to use the chemical injection device used for improving soft ground (No. 6).

The mixed liquid of sodium silicate and calcium chloride injected into the first tube 1 in the state where a low DC voltage is applied exits from the hole 5 of the first tube 1 and goes to the second tube 10. And penetrate the ground. This permeation is performed in the electroosmotic phenomenon by applying a DC voltage, and a chemical reaction and an ionic reaction are caused by the gelatinization time (gel time),
The area surrounded by the second pipe 10 indicated by the diagonal lines in FIGS. 4 and 5 is set as the solidified improved ground 11.

Next, an embodiment of the invention of claim 2 will be described.

When carrying out the invention of claim 2, first, the invention of claim 1 described above is carried out, and as shown in the plan view of FIG. 6, the first pipe 1 is inserted into the ground. The improved ground 1 in which the area surrounded by the second pipe 10 is solidified.
Set to 1.

Next, the first tube 1 is assumed to be the center of the circle, and a second circle 12 having a larger radius than the first circle 9 assumed in the invention of claim 1 is assumed. The radius of the second circle 12 is preferably about twice the radius of the first circle 9. And the second circle 1
The third pipes 13 are inserted into the ground along the line 2 at approximately equal intervals with a distance of about the radius of the first circle 9. Third tube 1
Similarly to the first pipe 1, 3 is a combination of one upper pipe 2, a proper number of middle pipes 3 and one lower pipe 4 shown in FIG. A number of holes 5 around the lower tube 4
Has been drilled, and the same operation is repeated for the work of inserting into the ground.

Next, all of the second tubes 10 are connected to the anode of the DC power source, all the third tubes 13 are connected to the cathode of the DC power source, and the second tube 10 and the third tube 13 are connected. To 15-25
Apply a DC voltage as low as a volt. Then, while continuously applying the DC voltage, a mixed solution of sodium silicate and calcium chloride is injected from the upper ends of all the second tubes 10.

The mixed solution of sodium silicate and calcium chloride injected into the second tube 10 in a state of being applied with a low DC voltage is discharged from the hole 5 of the second tube 10 to the third tube 13. The improved ground 1 which has penetrated into the ground toward the outer periphery of the improved ground 11 which has already been solidified as shown in FIG.
4 is formed.

By applying the above-described invention of claim 2 to the adjacent ground successively, a wide range of soft ground can be improved as shown in FIG.

[0025]

According to the invention of claim 1, the soft ground in a wide area can be improved by using one kind of pipe, and the pipe can easily be transferred to the construction site. Inserting a pipe into the tube also has the effect of making it easier to work without noise or vibration.

In addition to the above effects, the invention of claim 2 can improve the soft ground of a wider area, and the second tube that has been used as a cathode once can be used as an anode as it is.
It has the effect of requiring less work to insert a pipe into the ground.

[Brief description of drawings]

FIG. 1 is a plan view showing a state in which a pipe is inserted into the ground according to the invention of claim 1.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is an enlarged vertical sectional view of a tube.

FIG. 4 is a plan view showing a range in which the ground is improved by the invention of claim 1.

5 is a cross-sectional view of FIG.

FIG. 6 is a plan view when carrying out the invention of claim 2;

FIG. 7 is a plan view showing a range in which the ground is improved by the invention of claim 2;

FIG. 8 is a plan view of another embodiment of the invention of claim 2;

[Explanation of symbols]

 1 1st tube 5 hole 9 1st circle 10 2nd tube 12 2nd circle 13 3rd tube

Claims (2)

[Claims] 1. A first pipe having a large number of holes formed therein is inserted into the ground, and a plurality of second pipes having a large number of holes formed therein are first cylinders having the first pipe as a center of gravity. They were inserted into the ground at substantially equal intervals along a circle, and a DC voltage was applied between the first tube and the second tube using the first tube as an anode and the second tube as a cathode. A method for improving soft ground, comprising injecting a mixed solution of sodium silicate and calcium chloride into the first pipe in the state. 2. A first pipe having a large number of holes formed therein is inserted into the ground, and a plurality of second pipes having a large number of holes formed therein are first pipes having the first pipe as a center of gravity. They were inserted into the ground at substantially equal intervals along a circle, and a DC voltage was applied between the first tube and the second tube using the first tube as an anode and the second tube as a cathode. In this state, a mixed solution of sodium silicate and calcium chloride is injected into the first tube, and then a plurality of third tubes having a large number of holes are used as the first tube with the first tube as the center of the circle. The second tube as an anode and the third tube as a cathode, and the second tube and the third tube are inserted into the ground at substantially equal intervals along a second circle having a larger radius. A method for improving soft ground, comprising injecting a mixed solution of sodium silicate and calcium chloride into the second tube while applying a DC voltage between them.