JPS60223518A - Improvement work of weak and viscous ground - Google Patents

Abstract

PURPOSE:To complete drainage in a short time by eliminating the needs for burden of banking soil by a method in which many columns of a high-water absorptive high molecular material are erected in the weak and viscous ground in such a way as to cause the columns to swell by water absorption of the viscous soil among them. CONSTITUTION:Many column holes 2 are provided at intervals in the weak and viscous ground 1, and filled with a high water absorptive high molecular material 3, together with the surface soil 6 as needed. Since the high molecular material 3 (e.g., polyvinyl alcohol, polyethylene oxide, etc.) has high water absorbability, the water in the viscous soil 5 among the columns 4 is absorbed by the material 3 and the surrounding viscous soil 5 is compressed by the swelling of the material 3 itself. The water in the soil 5 can thus be squeezed out to enable the material 3 to absorb more water.

Description

[Detailed Description of the Invention] Industrial Application Field This invention is a method for improving soft and viscous soil that contains a large amount of moisture, and for making the ground firm by absorbing the moisture in the ground into pillars made of highly absorbent polymeric material. It is related to.

Conventional technology Conventionally, as an improvement method for soft and cohesive soil, the water contained in the soft and cohesive soil is drained out using drains to make the cohesive soil more dense and thereby strengthen the soil. Two methods are known: the sand drain method, in which the soil is embanked on the ground, and a load is applied to squeeze water out of the clay soil into the drain, and the paper drain method, in which paper is used instead of sand piles. However, these methods require a long period of 2 to 3 months to drain the clay soil,
The drawback was that it required heavy embankments filled with sand and paper, making construction difficult.

Purpose of the Invention The present invention has been developed in consideration of the drawbacks of the conventional construction method described above.The first object of the invention is to develop a soft and viscous soil base that does not require loading by embankment and can complete drainage in an extremely short period of time. The purpose of the second invention is to provide an improved construction method for soft and viscous soil, which is easy to construct and can provide a greater supporting capacity as the ground, in addition to the purpose of the first invention. It is to provide.

Structure of the Invention The structure of the present invention to achieve the above object is that, in the first invention, a large number of pillars (4) of super absorbent polymer material are erected at intervals in a soft and viscous ground. The second invention comprises an improved construction method for soft and cohesive soil in which the pillars absorb water from the cohesive soil between them and swell; A pipe is passed through the glued hole, concrete or sand is pressed into the bottom of the pillar through the glossy pipe, and the pillar is pushed up, replacing it with a concrete pillar or sand pillar.
It consists of an improved construction method for soft and viscous soil.

Example' Preferred embodiments of the invention will be described with reference to the drawings.

In FIG. 1, a large number of postholes (2) are provided at intervals in a soft and viscous ground (1), and the postholes (2) are filled with a superabsorbent polymeric material (3). This super absorbent polymer material (
For 3), in addition to the powder or granular material, bagged powder or granular material, sheet-like material, or solidified columnar material may be used. In this case, the solidified material may be press-fitted together with the guide without drilling holes in advance, and then installed by pulling out the guide. Since the polymeric material (3) is highly water absorbent, it absorbs moisture in the clay soil (5) surrounding the pillars (4) of the highly absorbent polymeric material, resulting in highly absorbent water as shown in Figure 2. Polymer material (3)
) As it swells, it compresses the surrounding viscosity (5), so water in the clay soil (5) is squeezed out, making the superabsorbent polymer material (3) even more likely to absorb water. The water that has been completely absorbed becomes a pillar (
4) The water in the clay soil (5) is retained and absorbed by the clay soil (5).In this way, the water in the clay soil (5) is absorbed by the column (4) made of super absorbent polymer material. Since the water content of the clay soil (5) itself can be reduced, the strength of the clay soil (5) can be improved and the soft and sticky soil slab (1) can be improved. 4) The K-absorbed water may be left as it is, or cement or lime may be mixed into it.The strength of the obtained soil (1) and the time required for it are determined by It can be controlled by the pitch and thickness of (4). (6) is used as necessary for topsoil (Sandmanto, etc.).

The superabsorbent polymer material mentioned above is one that has the function of causing moisture to move from the soft and viscous soil to the superabsorbent polymer material when the soft and viscous soil is brought into contact with the superabsorbent polymer material. Yes, natural or synthetic organic polymer compounds or modified products thereof, such as polyvinyl alcohol 0, ethylene oxide, sodium polyacrylate, potassium polyacrylate, polyacrylamide, carboxymethyl cellulose, vinyl alcohol-acrylic acid-1
-) IJum copolymer, vinyl alcohol-potassium acrylate copolymer, vinyl/lz:l-acrylamide copolymer, or crosslinked products of these polymers with dichloroacetic acid, epichlorohydrin, or other crosslinking agent, or Examples of these polymers include those in which hydrophilic groups are partially substituted. In addition, partial hydrolysates such as polyacrylonitrile and polyacrylic acid esters, sulfonated products of polystyrene, starch, acrylonitrile,
Graft copolymers such as methacrylate, etc., as well as superabsorbent polymer materials of these materials, with the addition of inorganic swelling materials such as bentonite, and inorganic adsorption materials such as modified slag are also included, especially vinyl. Alcohol-potassium acrylate copolymer, vinyl alcohol-maleate ester copolymer, acrylate grafted starch, vinyl alcohol-sodium acrylate copolymer, crosslinked polyacrylate, and modified polyvinyl alcohol are preferred. The properties of vinyl alcohol-acrylic acid potassium salt, which is one of them, are as follows.

Figure 3 shows the initial water absorption capacity for distilled water.
It has a water absorption capacity that is 900 times the weight of the resin.

゛Figure 4 shows a 1% saline solution, and its water absorption capacity is 90 times that of distilled water. decreases to Figure 5 shows the water retention effect.
Even when pressurized to 00G, there is almost no change in its water absorption capacity, and it has excellent water retention.

The following tests were conducted on a case where this resin was installed as a resin column in clayey soil.

A cylindrical acrylic resin container with an inner diameter of 60 wn and a height of 60 m is filled with terrestrial and marine clay, and a cylindrical vinyl alcohol/acrylic acid potassium salt with a diameter of 20 mn and a height of 60 ymn is placed in the center as a high absorption a. The entire specimen was made with the material inserted, and its moisture content and shear strength were tested. The results are shown in Tables 1 and 2.

Figure 6 shows a column of glue-like super absorbent polymer material that has absorbed water (4
) instead of a concrete column or sand column, use a pipe 76 such as a tremie pipe (when force is inserted, the super absorbent polymer material (3) that has absorbed water is glued, so the pipe (force cannot be inserted easily). When the concrete (8) or sand is pressed into the column (4) from the tip of the force that has reached the bottom of the column (4), the column (4) made of the glued super absorbent polymer material becomes an anti-friction material. As the concrete or sand is pressed in, the column (4) slides up through the clay soil (5') that has become hard due to absorption of water, and the column (4) made of super absorbent polymer material is replaced with a concrete column or sand column as shown in FIG. 7, so the soft and viscous ground (1) becomes even stronger due to the supporting capacity of the concrete column (9) or sand column.

Effects of the Invention Since the present invention has the above-mentioned configuration, the first invention can shorten the construction period because there is no need for loading by embankment unlike in conventional drain construction methods, and drainage can be completed in a very short period of about one week. In addition to being able to significantly shrink the ground, it also creates a foundation that can withstand soil structures and building foundations.Also, since the material is highly water-absorbent, it is easier to use super-absorbent polymer materials than sand piles or paper strips. It has the ability to absorb water from cohesive soil with a volume much larger than the volume of the pillars, so the amount of superabsorbent polymer material per unit volume is small, saving material costs. Since it is unnecessary and uses factory-manufactured materials, construction can be done cleanly and easily.

In addition to the effects of the first invention, the second invention also has the following advantages:
The pillars made of the superabsorbent polymer material of the first invention absorb water and have a glue-like shape, so they do not have any supporting force, but since they are replaced with concrete pillars or sand pillars, a large supporting force can be obtained, and even more Not only does it provide a foundation that can be used for large-scale earth structures and building foundations, but since the pillars made of super absorbent polymer material are glue-shaped, pipes can be inserted into the pillars to form concrete pillars or This has the effect of facilitating the construction of sand pillars.

[Brief explanation of the drawing]

FIGS. 1 and 2 show an example of the first invention, and FIGS. 3 to 5 are graphs showing the performance of superabsorbent polymer materials, and FIGS. 7th
The figures show embodiments of the second invention, and are longitudinal explanatory views. (1)... Soft viscous ground, (3)... Super absorbent polymer material, (4)... Pillar of super absorbent polymer material, (5
)・Cohesive soil, (7)・Pipe, (8)・Concrete, (9)・Concrete pillar. Representative Patent Attorney Kiyoshi Sakai Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 16 Soft and cohesive soil (a large number of pillars (4) made of super absorbent polymer material are erected at intervals in 11, and the pillars (4) are made of cohesive soil (5) between them. An improvement method for soft and viscous ground that absorbs water and swells. 2. A large number of pillars (4) made of super absorbent polymer material are erected at intervals in the soft and viscous ground (1). After the pillars (4) absorb water from the clay soil (5) between them and swell, a force is passed through the pillars (4) which have absorbed water and become glued, and a pipe (force Conc' through the bottom of said pillar (4)
J-) (8) Or, a method for improving a soft and viscous soil base by press-fitting sand to push up the column (4) and replacing it with a concrete column (9) or a sand column.