SU1076533A1 - Method of isolating subsoil water in watered soil - Google Patents

Abstract

A METHOD FOR INSULATING GROUND WATER ON IRRIGATED LANDS, which involves injecting a silica-containing reagent into the ground, characterized in that, in order to create an impervious screen at a predetermined depth, the groundwater level is lowered to this depth, after which silicon or a fluorine is injected into the ground, then the flutter or fluorine is lowered to this depth, then the groundwater is injected with silicon silicate or fluorine and then fluorine is lowered into the depth, then the groundwater is pumped into the soil or fluorite, or fluorine, then flutter flutter or fluorine will be pumped to the depth of the groundwater, after which the silicon water or fluoride will be pumped into the ground and then fluorine will be lowered to this depth.

Description

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The invention relates to the consolidation of soils and can be used in the technical melioration of soils on irrigated lands, for example, to combat the rise of groundwater levels and the secondary salinization of soils. A known method of fixing flooded non-bonded soils by pumping water-soluble fixative solutions in them, the soil mass is previously dried before the injection of solutions 1. The closest to the technical drying and the effect achieved is to fix water-saturated sandy soil, including with the aim of creating an anti-seepage screen for isolating groundwater by successively injecting an aqueous solution of sodium silicate and carbon dioxide into the soil through the same injection torus 2. A disadvantage of the known methods is the impossibility of creating an impervious screen at a predetermined depth. The purpose of the invention is to create an impervious screen at a given depth. The goal is achieved by the method of isolating groundwater on irrigated lands, including the injection of silica-containing reagent into the ground, previously reduced the level of groundwater to the depth of creating an impervious screen, after which silicon-oxide or silicon fluoride is injected into the ground. The dryness of the proposed method consists in the fact that after lowering the level of groundwater reagents are injected into the ground, interacting with water and forming poorly soluble compounds in the soil. Thus, the formation of an impervious screen is possible precisely at a predetermined depth from the surface of the earth, which is determined by the curve of the deformational funnel from a decrease in the level of groundwater. Silicon hydride or silicon fluoride can be used as reactants interacting with water. Silicon hydrides — compounds of silicon and hydrogen — are obtained by reacting diluted acids with magnesium silicide or as waste from the production of aerosil (white soot). Only saturated silicates of the general formula Si, H2M H-2 are isolated, and are obtained up to SigHj octosilane. The first of this series — SiH4 monosilane and SijHj disilane — are in a gaseous state at room temperature, and the rest are volatile liquids. The silicones are oxidized in air and decompose with water, for example, SijHg + 3HF-f 10H2. Both during oxidation and decomposition of water by silicon, a large amount of SiO is formed in the form of fine dispersions. Silicon dioxide, accumulating in the soil, almost completely clogs its pores, thereby creating a waterproof screen. Silicon fluoride acts in the same way, which reacts with water and calcium, magnesium and sodium salts dissolved in it to form poorly soluble compounds — sodium fluorosilicate, calcium silicates and magnesium. Due to the fact that silicon fluoride interacts with salts, it is advisable to use it when it is necessary to isolate the ground water of high salinity. Silicon fluoride can be obtained from the waste of chemical and metallurgical plants, where it is contained in an amount of up to 15-200/0. Silicon hydride and silicon fluoride are introduced into the soil in any quantities (depending on the required thickness of the formation) both in pure form and in any ratios at natural ambient temperature and pressure not higher than 1-10-10Pa. At the same time, 1.5-2 gram molecules of silicon dioxide are formed per gram molecule of the reagent. The method was tested in laboratory and field conditions. Under laboratory conditions, the effect of these reagents on changes in the porosity and permeability of water-saturated sandstones has been studied. In the first case, a mixture of monosilane and disilane in a ratio of 4: 1 in an amount of 10 m. This mixture is passed through columns of sandstone core 50 cm in height for 1 h. The results of measurements of open porosity (by volume method) before and after the experiment are presented in Table. 1. As can be seen from the data table. 1, watered sandstone samples almost completely lead to porosity (at values of 1-3%, the rock is almost waterproof). Similar laboratory tests were also carried out with silicon fluoride. As a reagent use wastes of production of the Kalush chemical-metallurgical plant of the following composition,%: silicon fluoride 12; silanes 4; chloroalkanes 5; fluoroalkanes 1; nitrogen 77 and argon 1. The results of core permeability tests before and after the experiments are given in table. , 2. The proposed method, as can be seen from the table. 2, reduces the permeability of the rock when pumping silicon fluoride by 10–20 times into it, and for the case of high salinity of groundwater, permeability is almost absent. The method has also been tested in the field. All conditions in the well. Well depth 5.2 m. Ground water is opened at a depth of 1.3 m. The whole section

wells composed of medium and fine-grained sands. After water lowering to the level of 4.8 m, 15 m of a mixture of m, it and disilane in the ratio 4: 1 is pumped into the well. Then, at a distance of 3 and 5 m from the injection well, pits 1 and 2 pass, in which the thickness, impervious screen, porosity and permeability of the rocks composing it are determined.

The results of these tests are presented in Table. 3

From tab. 3 it can be seen that, at a distance of 7 m from the well, an anti-filtration screen with a thickness of 0.3–0.7 m, almost devoid of porosity, was created, and near the injection well it was almost waterproof. At the same time, this screen strictly rises to a lower level of groundwater.

Thus, with an optimal choice of the distance between the injection wells, the proposed method allows the creation of an impervious screen in the soil at a predetermined depth

from the surface, isolating groundwater and preventing it from rising above a critical level, which, in turn, reduces the likelihood of secondary soil salinization on irrigated lands.

Table 1

Sandstone Vodoprovna

Mineralization

Breed

1.4

11.5

Permeability, millidarcy

Table 3

Claims (1)

METHOD FOR INSULATING GROUND WATER ON IRRIGATED LANDS, including the injection of a siliceous reagent into the soil, characterized in that, in order to create an anti-filter screen at a given depth, the groundwater level is first reduced to this depth, after which silica hydrogen or silicon fluoride is injected into the soil. 05 joint venture