JPS59155488A - Soil conditioning - Google Patents

Abstract

PURPOSE:To reduce the water content of soft soil and to condition it into good- quality one with increased strength by water absorption and gelation, by mixing a highly water-absorptive resin with a high water-content soft soil. CONSTITUTION:A highly water-absorptive resin such as potassium acylate, if necessary, contg. dry particulates is mixed with soft soil of a high water content, to reduce said content by absorbing and gelling water contained in the soil with the resin. For conditioning soft soil on the surface layer of earth on site, the soft soil is scraped if necessary and a small amt. of the highly water-absorptive resin is spread on its surface, mixed by a bulldozer, etc. and evenly rolled by a roller, etc. In the case of sludge, etc., it is sucked into kneader by a squeezing pump, etc., in which it is mixed with said resin, and then carried out by a belt conveyer, truck, etc., according to request.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a construction method for improving soft soil encountered in civil engineering and construction work.

In recent years, dredging, securing work scaffolding and traffability of earth-moving machinery at landfills and industrial waste disposal sites, and
There is an increasing trend in the number of improvements being made to sludge deposited on canals and the seabed, as well as soft soil in earthen structures.

As a construction method for improving these soft soils, methods of chemically solidifying the soft soil using cement, quicklime, etc. have been widely used.

However, although the improvement method using cement is extremely effective for improving sandy soil, it is not very effective for soils with high water content and specific viscosity, or organic soils, and increasing the amount added more than necessary is economically disadvantageous. There was one problem, such as: In addition, although the improvement method using quicklime is effective for improving not only soils such as high water content specific viscosity soils and organic soils, but also sandy soils,
There were problems such as slow reaction rate, difficulty in handling, and high cost.

The present invention has been made in view of the above-mentioned problems, and its purpose is to improve the soft soil encountered in earthworks in an extremely short period of time that is advantageous in terms of economy and handling, regardless of the type of soil. The goal is to provide new construction methods that can be used.

According to the present invention, a highly water-absorbing tree made by adding dry powder to soft soil having a high water content ratio as required, the inventors have previously developed a highly water-absorbing tree that is completely non-toxic and absorbs several hundred times more water. A super absorbent resin that absorbs and swells thousands of times and turns into a gel, does not dissolve in water, and does not release water even when a single pressure is applied. It has been found to be extremely effective when used for improvement.

A good example of the superabsorbent resin according to the present invention is potassium acrylate, and other examples include starch grafted with acrylic acid, acrylonitrile hydrolyzate, polyvinyl alcohol/maleic acid copolymer, and vinyl alcohol/acrylic acid. There are salt copolymers, etc.

When these granular super-absorbent resins are added to and mixed with a powder having a high water content ratio, water is confined in a very short time in the fine mesh space surrounded by the polymer forming the resin. That is, it is absorbed and gelled. Therefore, the soft, defective top 4'J is converted into a good quality with increased strength due to a decrease in the top 3' water ratio.

Therefore, in order to improve the soft surface layer of the ground at the site, the soft soil is either left as it is or is scraped up, and a small amount of the above-mentioned super absorbent resin is added and sprayed on the surface, and then a bulldozer or a soft ground improvement tool is used. Mix using a mud truck, etc. In this way, the soft soil that has been dehydrated with the resin is improved. When this improved soft soil is compacted using a roller or the like, the desired purpose can be obtained.

In addition, in order to improve slurry-like soft soil such as sludge or sludge, the soft soil is sucked up using a squeeze pump, Mono pump, moisture jet pump, etc., and introduced into a kneading machine. Add and mix super absorbent resin. In this way, the soft soil that has been dehydrated with the resin is improved. This improved soft soil is then transported out using a bell conveyor, trunk, etc. depending on the desired use.

By the way, due to its characteristics, the powdery superabsorbent resin easily absorbs moisture in the air and sticks to each other. Therefore, if these resins are pre-impregnated with dry granules such as dry clay or dry sand as necessary, it will be difficult to handle during construction.

As described in detail, the present invention involves adding and mixing a small amount of super absorbent resin to weak soil with a high water content ratio, which is encountered in civil engineering and construction earthworks, to absorb moisture in the soil and turn it into a gel. Therefore, it is economical because soft soil can be converted into improved soil with reduced JJF water ratio and increased strength in a very short period of time.2.It is extremely advantageous in terms of shortening the construction period and handling. be.

Examples will be shown below to clarify the effects of the present invention described above.

(Example) The following table shows Kanto loam, which is a soft soil (water content ratio / 3%), and powdered potassium acrylate salt, which is a super water-absorbent resin (product name:
Arasorb) was added and mixed, and the slump value was determined by the slump test (J Engineering SA, /10/) of the sample soil immediately after mixing, and the cone index q was determined by a portapul cone penetrometer of the same test soil after the slump test, c.

According to this, by adding and mixing an extremely small amount of superabsorbent resin, the water in the sample soil is absorbed and gelled in a short period of time, and the apparent water ratio decreases and the slump value decreases. It was confirmed that fluidity was lost and strength increased.

Claims (1)

[Claims] If necessary, a super absorbent resin containing dry powder is added and mixed into soft soil with a high water content ratio, and the water in the soil is absorbed and gelled by the super absorbent resin. A soil improvement method characterized by lowering the moisture content of soft soil.