JPH0691107A - Selective-coagulation liquid stabilizer used in underground continuous wall - Google Patents

Abstract

PURPOSE:To provide a liq. stabilizer used in digging and constructing an underground continuous wall, which is selectively coagulated and capable of selectively coagulating and precipitating only the sediment and slime in the dug ditch wall. CONSTITUTION:This liq. stabilizer is used when an underground continuous wall is dug and constructed to selectively coagulate and precipitate the sediment and slime. The stabilizer consists of an anionic emulsion-type polymer, a low- viscosity polymer and a swelling clay.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a selective cohesive stabilizing solution used for underground continuous walls, and more specifically, it selectively selects excavated sediment and slime used for excavation and construction of underground continuous walls. The present invention relates to a stabilizing solution that causes aggregation / precipitation.

[0002]

2. Description of the Related Art Stabilizers used for underground continuous walls are basically used for stabilizing excavation trench walls. However, the functions required for stabilizing liquid are not only the stability of excavation trench walls, but also the function as a replacement fluid for concrete, the function of holding excavated soil particles and transporting them to the ground, and the amount of excavated soil and slime mixed in the stable liquid. The function of accelerating sedimentation is required.

Conventionally, the function of accelerating the settling of slime is not considered important, and the sediment content mixed in the stabilizing solution is removed from the stabilizing solution by gravity's natural settling or mechanical separation means using a decanter or the like. It was However, when excavating silty ground, these methods are not sufficient, and the sediment is always mixed in the stabilizing liquid. At present, the method of substituting the entire amount with the liquid is adopted.

[0004]

By the way, in the conventionally used stabilizing solution having an aggregating action, there is a tendency that even bentonite and the like, which are necessary as a constituent component of the stabilizing solution, are aggregated. That is, the present situation is that the stabilizing solution itself does not have selective aggregation properties.

The present invention aggregates excavated earth and slime components used in excavation and construction of underground continuous walls as described above.
This is done in view of the current situation and problems of the stabilizing solution to be precipitated, and the purpose is to make the stabilizing solution itself have selective cohesiveness so that only the excavated sediment and slime are selectively aggregated and Provides a stabilizing solution that can be precipitated,
Moreover, in order to ensure the function as a replacement fluid for concrete and the like, it is to provide a selective cohesive stabilizing solution for use in continuous underground walls that does not need to be replaced with a good quality stabilizing solution.
That is, the stabilizing solution of the present invention realizes to have the same function as that of the stabilizing solution in which the total amount of the stabilizing solution is replaced by the conventional method by performing the primary slime treatment.

[0006]

Means and Actions for Solving the Problems
As a result of intensive research on solving the above-mentioned problems, a stabilizing solution capable of selectively aggregating and precipitating excavated sediment by using an anionic emulsion-type polymer as an aggregating agent and further adjusting the mixing ratio to an appropriate level was obtained. I found what I could get.

The present invention is based on the above findings and ideas, and the gist thereof is a stabilizing solution for aggregating and precipitating sediment and slime used for excavation and construction of underground continuous walls. It is a selective coagulant stabilizing liquid used for underground continuous walls, which is characterized by blending an emulsion type polymer, a low viscosity polymer and a swelling clay.

The selective flocculating stabilizer according to the present invention is a mixture of an anionic emulsion type polymer, a low viscosity polymer and swelling clay. It is composed of an acrylamide / Na acrylate copolymer, manufactured by Ternite Co., Ltd., and is referred to as a trade name "Supercoat" (hereinafter referred to as "S" in the present invention) and has a milky white appearance. Liquid with a specific gravity of 1.01 to 1.02 and a pH of 8.2
It is about 8.6. And it is preferable to mix this S in a ratio of 0.05 to 0.5% in the selective coagulant stabilizing solution according to the present invention. This is because if S is added in an amount of more than 0.5%, the viscosity is drastically increased, and the smooth sedimentation of sediment and slime in the stabilizing solution is significantly impaired.

Further, a low-viscosity polymer is blended as another component constituting the selective coagulant stabilizing solution according to the present invention. An example thereof is "TP-30" manufactured by Ternite Co., Ltd.
It is preferred to use the "L" equivalent. The blending ratio is preferably 0.05 to 1%. This is because if it is mixed in excess of 1%, the viscosity will increase sharply and the smooth sedimentation of earth and sand and slime in the stabilizing solution will be significantly impaired. Further, swelling clay is required as another compounding ingredient, and a typical example thereof is bentonite. And the blending ratio is preferably 0.5 to 5%.
This is because if the content exceeds 5%, the viscosity increases sharply and the smooth sedimentation of the sediment and slime in the stabilizing solution is significantly impaired.

Next, the results of testing the selective cohesiveness of the selective cohesiveness stabilizing liquid according to the present invention will be described. A standard solution, which is a conventional stabilizing solution, and a selective flocculating stabilizing solution according to the present invention are prepared in the following mixing ratios. Standard liquid Bentonite (Gunma 300 #) 1% and low-viscosity polymer 0.2% Inventive liquid Standard liquid containing 0.2% of the above S Next, each of these liquids and clay was added to each liquid. (SCP
When the relationship between the position (depth) in the graduated cylinder and the change in liquid specific gravity was examined for each of the mixture of -A) at a ratio of 5%, the results shown in Fig. 1 were obtained.

As is clear from the results shown in FIG.
In the reference liquid and the liquid of the present invention in which S is added to the reference liquid, the specific gravity does not change with depth. In other words, it indicates that no aggregation / precipitation occurred (in Fig. 1, the results for the standard solution only)
(White circle) is almost unclear on the graph because it almost matches the result (black circle) of the solution of the present invention). And when clay is mixed with the reference liquid (white triangle), the specific gravity gradually increases according to the depth, which indicates that the clay particles are naturally settling due to their gravity. On the other hand, when clay is mixed with the liquid of the present invention (black triangle), the specific gravity is rapidly increased according to the depth. This indicates that the clay particles were selectively aggregated and settled by the action of the aggregating agent.
It should be noted that when the sediment content is aggregated by the treatment with the selective coagulant stabilizing solution according to the present invention, and the sediment content is sedimented in the standard solution which is a conventional stabilizing solution, when observed by a microscope, respectively, the former aggregates. Became floc, and the latter was particles in which the particles were dispersed in a stabilizing solution.

[0012]

EXAMPLES The present invention will be described below based on examples. As the selective coagulant stabilizing solution according to the present invention, a stabilizing solution having the composition shown in Table 1 was used, and for comparison, the above-mentioned reference solution which is a conventional stabilizing solution was used, and confirmation of selective cohesiveness was carried out by a working process. Did.

[Table 1] Stabilizer formulation

Table 2 shows an overview of the soil quality of Funabashi City, Chiba Prefecture, where the construction work was carried out. An MHL excavator (bucket type) was used for excavation.

[Table 2] Outline of soil quality

FIG. 2 shows the relationship between the settling time of slime (including excavated earth and sand) measured in the excavation trench and the slime deposition rate. As is clear from this figure, when the selective coagulant stabilizer according to the present invention is used, the sedimentation speed is higher than that of the conventional stabilizer because the slime component becomes floc. Further, when the precipitate at this time was observed with a microscope, it was aggregated and had a floc shape.

Next, Table 3 shows the general property test results of the selective coagulant stabilizing solution according to the present invention during excavation. The test liquid in this case was collected immediately after the excavation was completed. As is clear from Table 3, the stabilizing solution of the present invention showed the same tendency as that of the conventional stabilizing solution, and no special management method was required.

[0016]

[Table 3] Results of stable liquid management test

Further, the stabilizing liquid used for the underground continuous wall is
It should not adversely affect the bond strength between the reinforcing bar and concrete. Therefore, Table 4 shows the results of testing the adhesive strengths of the stabilizer of the present invention and the conventional stabilizer. As is clear from Table 4, it can be confirmed that even when the stabilizer of the present invention is used, the adhesive strength characteristic is equal to or higher than that when the conventional stabilizer is used.

[0018]

[Table 4] Adhesive strength test results

[0019]

EFFECTS OF THE INVENTION According to the selective coagulant stabilizer used for underground continuous walls according to the present invention, an anionic emulsion-type polymer is used as a coagulant, and a low-viscosity polymer and swelling clay are appropriately added. By mixing in a ratio, the stabilizing solution itself has a selective cohesive property, and only the sediment and slime components can be selectively aggregated and precipitated in the excavation trench. And, in order to secure the function as a replacement fluid for concrete like the conventional stabilizing solution, it is not necessary to replace it with a high-quality stabilizing solution, and it is possible to provide a selective cohesive stabilizing solution to be used for underground continuous walls. it can. Furthermore, the selective coagulant stabilizing solution according to the present invention flocculates the sediment and the slime in the form of flocs, so the lost mud (a phenomenon in which the stabilizing solution flows out into the ground to be excavated, which has been a problem in the construction of underground continuous walls in the past )
Against this, the floc-like aggregated sand and slime components exert a clogging effect. Therefore, when excavating the ground where the mud is expected to be lost using the conventional stabilizing solution, the stabilizing solution used was blended with the mud-preventing material, but the present invention does not require this mud-preventing material. It also has the effect of doing.

[Brief description of drawings]

FIG. 1 is a position (depth) in a measuring cylinder.
3 is a graph showing the relationship between the change in liquid specific gravity and

FIG. 2 is a graph showing the relation between the sedimentation time of slime and the deposition rate.

Front page continued (72) Inventor Fujio Domon 261-1 Momoka, Hino-shi, Tokyo 261-1 (72) Inventor Iwa Sato 687 Naganuma, Hachioji, Tokyo (72) Inventor Masahiro Miura 3-7-6 Sekima, Sakado-shi, Saitama (72) Inventor Shinya Matsushita 1-38 Kurumada-cho, Showa-ku, Nagoya-shi, Aichi

Claims (3)

[Claims] 1. A stabilizing solution for aggregating and precipitating sediment and slime used for excavation and construction of an underground continuous wall, which comprises an anionic emulsion type polymer, a low viscosity polymer and a swelling clay. The selective coagulant stabilizing liquid used for underground continuous walls characterized by the above. 2. The anionic emulsion-type polymer is 0.1.
The selective cohesive stabilizing liquid for use in the underground continuous wall according to claim 1, which is blended in a proportion of 05 to 0.5%. 3. The swellable clay is bentonite,
The selective cohesiveness stabilizing liquid for use in an underground continuous wall according to claim 1, which is blended in a ratio of 0.5 to 5%.