JPH0814103B2 - Electrochemical soil stabilization method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrochemical soil stabilization treatment method.

[0002]

2. Description of the Related Art Generally, the liquefaction phenomenon in soft sand or soft cohesive ground means that loose ground water with shallow groundwater is subjected to repeated shearing forces due to earthquakes, etc. It is a phenomenon that these particles come off and float in the interstitial water and eject as muddy water to the ground.

As measures for preventing liquefaction in this soft sand ground or soft cohesive ground, there are measures for preventing the occurrence of liquefaction and measures for assuming the occurrence of liquefaction. The former one is a replacement. There are various construction methods such as construction method, stabilization treatment method, compaction construction method, gravel drain construction method, groundwater level lowering construction method, embankment construction method and the like, and the latter method includes sheet pile construction method, pile foundation construction method and solid foundation construction method.

However, the replacement method, the embankment method, and the stabilizing method, which are measures for preventing the occurrence of liquefaction, require a long time and are economically expensive. In addition, the compaction method cannot be used for the foundation of existing structures because it is greatly affected by noise and vibration, and the gravel drain method has the problem that the ground around the piles will sink after the occurrence of liquefaction and the groundwater level lowering method. There was a problem that each had a great influence on the surrounding ground. Furthermore, the pile foundation method has a problem in that the horizontal resistance is evaluated and maintained, and the solid foundation method is effective only for light structures.

Therefore, in recent years, a soft sand ground or a soft cohesive ground can be economically improved without generating noise and vibration, and as a liquefaction prevention method applicable to the foundation of an existing structure, a so-called electric A method called the migration method has been developed.

As shown in FIG. 7, the positive and negative electrodes 10 and 20 are connected to a soft sand ground or a soft cohesive ground 30.
They are vertically embedded in each other, and a direct current is passed between these electrodes to cause a positive sticky or cohesive electrolyte to migrate from the anode 10 side to the cathode 20 side, or to the cathode 20 side. In order to increase the viscous resistance or the consolidation strength of the soil particles, the negative or sticky or sticky electrolytic substance is migrated to the anode 10 side and adhered to the soil particles.

[0007]

However, the above-mentioned liquefaction prevention construction method has a positive or negative adhesion between the positive and negative electrodes vertically embedded in the soft sand or soft cohesive ground. In order to migrate electrophoretic or solid electrolytes, these electrolytes can only migrate in a narrow range, that is, in point units, and when this is attempted to migrate in a wide range, that is, in plane units, the result in FIG. As shown, many positive and negative electrodes had to be buried.

The present invention has been made in view of the above problems, and an object thereof is to improve soft sand ground or soft cohesive ground in a wide area at one time to prevent liquefaction from occurring. Is.

[0009]

To achieve the above object, the first invention in the electrochemical soil stabilization treatment method of the present invention is a box for an anode and a cathode provided with a perforated plate in a soft sand ground. The body is buried at appropriate intervals with the porous plates facing each other, and a positively charged electrolytic substance is put in the box body of the anode, and a positive current is applied between these two electrodes to carry out the positively charged electrolysis. To migrate the substance to the box side of the cathode to adhere to the soil particles,

A second aspect of the present invention is that a box body of an anode and a cathode provided with a perforated plate in a soft sand ground is embedded at appropriate intervals with the perforated plates facing each other, and the box of the cathode is negative. By placing a charged electrolytic substance and applying a direct current between these electrodes, the negative charged electrolytic substance is caused to migrate to the box side of the anode and adhere to the soil particles. And

In a third aspect of the invention, a box body of an anode and a cathode provided with a perforated plate in a soft sand ground is embedded at appropriate intervals with the perforated plates facing each other, and the box body of the anode is positive. Electrolyte having a positive polarity, and a negatively charged electrolytic substance in the negative electrode box body, respectively, by applying a direct current between these two electrodes, the positively charged electrolytic substance to the negative electrode box side, A negative electrolyte is migrated to the box side of the anode to adhere to the soil particles.

In a fourth aspect of the present invention, a box body of an anode and a cathode provided with a perforated plate in a soft cohesive ground is embedded at appropriate intervals with the perforated plates facing each other, and the box body of the anode is provided. By putting a solution containing a surfactant and passing a direct current between these two electrodes, the solution containing the surfactant is migrated together with the interstitial water between the soil particles into the box of the cathode, and the solution is collected. It is a configuration characterized by dehydrating from the box,

In a fifth aspect of the present invention, a box body of an anode and a cathode provided with a perforated plate in a soft cohesive ground is embedded in the box body of the anode with the perforated plates facing each other at appropriate intervals. By injecting a solution containing an electrolyte and passing a direct current between these two electrodes, the solution containing the electrolyte is migrated together with the interstitial water between the soil particles into the box of the cathode, and collected from the box of the cathode. That is, the structure is characterized by dehydration.

[0014]

According to the above construction, the positive or negative electrolytic substance in the box of the anode and the cathode in which the perforated plates are embedded in the soft sand ground with the porous plates facing each other is provided between the two electrodes. By flowing the direct current flowing to the anode box side or the cathode box side respectively, it adheres to a wide range of soil particles at one time and adheres between the soil particles, and the viscosity of the sand ground is efficiently spread over a wide range. Increase resistance or consolidation strength.

Further, the solution containing the surface-active agent injected into the box on the anode side significantly reduces the surface tension of the water in the soft and viscous ground, which causes friction when the water moves in the ground. Since the resistance is reduced and pore water easily separates from the skeleton of soil particles, a large amount of water is dehydrated in a short period of time. Further, as the surface tension is reduced, the tensile force due to the meniscus generated between the skeletons of the soil particles is reduced, the occurrence of cracks is reduced, and the amount of shrinkage of the entire ground is increased.

In addition, since the solution containing the electrolyte injected into the box on the anode side separates the adsorbed moisture on the surface of the soil particles by the action of the electrolyte, it is possible to increase the dehydration amount of the ground and the dehydration period. To shorten.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the electrochemical soil stabilization treatment method of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of the first invention in the electrochemical soil stabilization treatment method of the present invention.

For liquefaction in the soft sand ground M, the resistivity FL to liquefaction is calculated by FL = R / L (where R is the dynamic shear strength ratio and L is the shear stress ratio during earthquake). When the value of this resistivity is 1.0 or more, it is determined that the ground is not liquefied, and when it is 1.0 or less, the ground is liquefied.

In this embodiment, a liquefiable soft sand ground M having an average particle diameter (D50) of soil of 0.6 mm≤D50≤2.0 mm and a resistivity FL of 0.806 is used. Anode plates 1 and 2 made of metal or carbon fiber are embedded in the soft sand ground M with the porous plates 3 facing each other at intervals of 0.5 to 2.0 m (FIG. 1).

The boxes 1 and 2 have a length over the entire length in the horizontal direction or the entire length in the vertical direction of the soft sand ground M, and the perforated plates 3 are opposed to each other as shown in the vertical sectional view of FIG. Buried in multiple rows along the horizontal or vertical direction. Further, as shown in FIG. 6, this embedding can be performed by alternately embedding the anode box 1 and the cathode box 2 having the porous plates 3 on both sides. As the electrolytic substance 4, sodium bicarbonate, sodium aluminate,
Iron hydroxide, aluminum oxide, etc. can be used.

Then, the anode box 1 is filled with a sticky electrolytic substance 4 containing a positive clay mineral, and the space between the anode box 1 and the cathode box 2 is 0. 1-5
When a direct current of V / cm is continuously applied for about 5 to 6 hours to 5 to 6 days, the positive sticky electrolytic substance 4 in the anode box 1 is passed through the holes 3a of the porous plate 3 to the cathode box. By migrating to the 2 side and adhering to the soil particles and adhering the sand particles to each other, it is possible to increase the viscous resistance of the sand ground M, which is soft per surface unit, that is, over a wide range at once.

As described above, as shown in Table 1 below, the electrolytic substance 4 containing the clay mineral was mixed in the liquefied ground having a resistivity FL value of 0.806 to be liquefied and electrophoresed. The average particle size (R2) of soil increases over a wide range, and the FL value for liquefaction is 0.806 to 1.9.
Since it is 17, the liquefaction of the soft sand ground M can be prevented.

The same results as in Table 1 above can be obtained by filling the solid electrolytic substance 4 containing calcium or the like in addition to the sticky electrolytic substance 4 described above.

[0024]

[Table 1]

In Table 1 above, FL is the liquefaction resistivity, R is the dynamic shear strength ratio, L is the earthquake shear stress ratio, and R1 is a function of the N value and the effective loading pressure σ'v. The first term of the dynamic shear strength ratio R represented is R2, the second term of the dynamic shear strength ratio R represented by the function of the average particle diameter D50, and the third R3 is the function of the fine particle content ratio FC. The third term of the dynamic shear strength ratio R, r
d is the reduction factor of the shear stress ratio during an earthquake in the depth direction, ks is the design horizontal seismic intensity on the ground surface used for liquefaction determination, σv is the total loading pressure, σ′v is the effective loading pressure, and N is the standard penetration test. The N value, D50, obtained from the above, is the average particle size of soil.

In the second invention of the present invention, the box body 2 for the cathode in the same soft sand ground M as the first invention is also used.
Contains a sticky electrolytic substance 4 containing a negative clay mineral, or a solidifying electrolytic substance 4 containing calcium or the like, or an aqueous solution obtained by dissolving a cement-based solidifying material, or a metallic substance. It is possible to obtain the same results as in Table 1 by filling the anode box body 1 side with an aqueous solution and performing electrophoresis (FIG. 3).

Furthermore, the third invention of the present invention is also the same as the above-mentioned first invention, but is the same as the first invention.
Electrolytic substance 4 containing clay minerals that are positive for
, And the negative electrode box body 2 is filled with a viscous electrolytic substance 4 containing a clay mineral having a negative polarity. The same results as in Table 1 can be obtained by subjecting the charged electrolytic substance 4 to electrophoresis on the side of the anode box 1 respectively (FIG. 4).

The fourth aspect of the invention is to embed anode and cathode boxes 1 and 2 in a soft cohesive soil M having a water content of 62% as shown in FIG. [Mimus Yushi Kagaku Co., Ltd. "Mimas L" (containing 16% surfactant)]
A solution prepared in a ratio of 10 g to 20 g of water was placed and left for several days, and when a current was applied between the electrodes for 28 hours, the solution of the surfactant migrated together with the interstitial water into the cathode container 2 and was collected. The water content of the soft cohesive ground decreased from 62% to 36.5% by pumping water from the cathode tube.

In the fifth invention, the water content is 62 as in the above.
Anode and cathode boxes 1, 2 in a soft cohesive ground M of 2%
Embedded in the box body 1 of the anode, an aqueous solution of 1 g of alum (potassium aluminum sulfate) and 99 g of water was placed as an electrolyte and left for several days, and then the electrodes were energized for 28 hours to form a gap between the electrolyte solutions. The water content of the soft viscous ground M is 62% to 37.7 by being electrophoresed together with water into the cathode tube body 2 and being absorbed by the pump.
Fell to%.

[0030]

As described above, according to the present invention, the soft sand ground or the soft viscous ground ground can be uniformly and economically spread over a wide area at a time without causing noise or vibration. It can be improved to prevent the occurrence of liquefaction.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state where an anode box and a cathode box are embedded.

FIG. 2 is a vertical cross-sectional view in which a positive electrolytic material is put in a box of an anode.

FIG. 3 is a vertical cross-sectional view in which a negative electrolyte is put in a cathode box.

FIG. 4 is a vertical cross-sectional view in which an anode box is filled with a positive electrolyte and a cathode box is filled with a negative electrolyte.

FIG. 5 is a cross-sectional view showing a state in which an anode box body and a cathode box body are embedded.

FIG. 6 is a cross-sectional view showing a state in which an anode box body and a cathode box body having porous plates on both sides are alternately embedded.

FIG. 7 is a plan view showing a conventional example in which a container for an anode and a container for a cathode are vertically embedded.

[Explanation of symbols]

 M Soft sand ground 1 Anode box 2 Cathode box 4 Electrolyte

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuzuru Murasawa 1-36-22 Minamiono, Ichikawa City, Chiba Prefecture (72) Inventor Takeshi Konishi 3-5-3-101 Makuhari Nishi, Chiba City, Chiba Prefecture (72) Inventor Futoshi Kubota 5-15-7 Inage Higashi, Chiba City, Chiba Prefecture Mitsui Fudosan Construction Co., Ltd. Inage Dormitory (56) Reference JP-A-64-52906 (JP, A)

Claims (5)

[Claims] 1. An electrolysis positively charged in a box body of the anode, in which a box body of an anode and a cathode having a perforated plate in a soft sand ground is embedded at appropriate intervals with the porous plates facing each other. An electrochemical soil stabilization treatment method characterized in that a substance is put in and a direct current is passed between both electrodes to cause the positively charged electrolytic substance to migrate to the box side of the cathode and adhere to the soil particles. 2. An electrolysis system in which a box body of an anode and a cathode provided with a perforated plate in a soft sand ground is embedded at appropriate intervals with the perforated plates facing each other, and the box body of the cathode is negatively charged. An electrochemical soil stabilization treatment method characterized in that a substance is put in and a direct current is passed between these electrodes to cause the negatively charged electrolytic substance to migrate to the box side of the anode and adhere to the soil particles. 3. An electrolysis positively charged in the anode box body by burying anode and cathode box bodies each having a perforated plate in a soft sand ground with the porous plates facing each other at appropriate intervals. A negative electrode electrolyte was put in the cathode box body, and a positive current was passed between these electrodes to cause the positive electrolyte material to move to the cathode box side and negative side. An electrochemical soil stabilization treatment method characterized in that electrolytic substances are migrated to the box side of the anode and attached to soil particles. 4. A box body of an anode and a cathode provided with a perforated plate in a soft cohesive ground is embedded at appropriate intervals with the perforated plates facing each other, and a surfactant is placed in the box body of the anode. The solution containing the surfactant is put into the cathode box by pouring a direct current between these electrodes, and the solution containing the surfactant is migrating to the cathode box together with the interstitial water between the soil particles, and dehydrated from the cathode box. An electrochemical soil stabilization treatment method characterized by: 5. A box body of an anode and a cathode provided with a perforated plate in a soft cohesive ground is embedded at appropriate intervals with the perforated plates facing each other, and an electrolyte is contained in the box body of the anode. By injecting the solution and passing a direct current between these electrodes, the solution containing the electrolyte is allowed to migrate to the cathode box together with the interstitial water between the soil particles, and is then dehydrated from the cathode box. Characteristic electrochemical soil stabilization treatment method.