RU2534862C1 - Composition for sandy soil reinforcement - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: composition for sandy soil reinforcement, comprising a filler and a binder component, and the filler comprises sand milled to fine dispersion (74-136 nm), and the binder component is used as saponite-containing material milled to microdispersed state (265-451 nm) isolated from pulp of tailing dump of industrial ore dressing of diamond field deposit, with the following ratio of components, wt %: saponite-containing material 3-6, sand - the rest.

EFFECT: improving the strength characteristics of sandy soil.

2 tbl, 3 dwg

Description

The invention relates to the field of construction of road and other bases and can be used to strengthen sandy soils.

Existing compositions for strengthening sandy soils are costly and time-consuming, which require special components.

Known composition for strengthening sandy soil [Auth. USSR No. 616354, IPC E01C 7/36, C08L 95/00, 1978]. The invention is aimed at strengthening sandy soil with a composition comprising a modifier of bitumen emulsion, sulphite-alcohol stillage, additives and water, while liquid glass is used as an additive.

The disadvantages of the composition are its multicomponent nature, the complexity of exposure in the process and insufficiently high strength characteristics of the fixed soil.

Known binder for fixing sandy soil [Auth. USSR No. 1796743, IPC E02D 3/12, C09K 17/00, 1993]. The invention is aimed at strengthening sandy soil with a binder, including a modifier from technical lignosulfonate, wood resin and water.

The disadvantages of the composition are the difficulty of holding the components in the process, the additional energy consumption that is spent on heating the wood resin, and insufficiently high strength characteristics of the fixed soil.

The closest analogue of the claimed invention is a composition for fixing sandy soil [Auth. USSR No. 1165705, IPC E02D 3/12, Е01С 3/04, 1985]. The invention is aimed at strengthening sandy soil with a composition that includes a modifier from spent petroleum products and hydroxy acids.

The disadvantages of the composition are the insufficiently high strength characteristics of the fixed soil and the additional expenditure of energy spent on heating the spent oil products.

The objective of the present invention is to increase the strength characteristics of sandy soil, namely the increase in specific adhesion without changing the angle of internal friction by more than 4%.

The problem is achieved in that the composition as a modifier contains fine sand and microdispersed saponite in the following ratio of components, wt.%:

saponite-containing material 3-6;

sand - the rest.

The following raw materials are used: river polymineral sand (the main constituent minerals: quartz, calcite, feldspars, gypsum, mica), grain sizes from 1.6 to 1.8 mm, previously washed from clay inclusions, and saponite-containing material isolated from the pulp of a tailing pond for industrial processing of ores from a diamond deposit.

The modifier is prepared as follows. Sandy soil, previously washed from clay inclusions, is dried to constant weight at a temperature of 110 ° C. The source material is ground by mechanical dispersion using a Retsch PM100 planetary ball mill (grinding time 60 minutes at 420 rpm, 80 ° C). Then, the obtained fraction is subjected to wet grinding for 5 hours in a planetary ball mill (420 rpm). A sample of saponite-containing material is dried to constant weight at a temperature of 110 ° C. The source material is ground by mechanical dispersion using a Retsch PM100 planetary ball mill (grinding time 120 minutes at 420 rpm, 80 ° C). Particle size of the samples is determined using the Delsa Nano Series Zeta Potential and Submicron Particle Size Analyzers.

For experiments, samples of ground sand with an average particle size of 102 ± 34 nm, saponite-containing material - 361 ± 96 nm are used. Their data are characterized by the specific surface area S _yd by the method of nitrogen sorption on an Autosorb-iQMP analyzer. The following specific surface values were obtained for the samples: sand - 8580 m ² / kg, saponite-containing material - 173429 m ² / kg.

According to the method based on measuring the contact angle of the surface of the sample with a water-ethanol solution and implementing the method of G.A. Zisman, the critical value of the surface tension (σ _k ) of the binary system of finely dispersed sand - microdispersed saponite is determined when the mass fraction of the latter in the composite is varied in the range 0 ÷ 2%. The upper limit of the content of saponite-containing material in the mixture is due to the fact that the uniformity of the surface of the system is violated, which is manifested in the impossibility of fixing a pseudo-equilibrium state when applying a standard water-ethanol solution. Determination of the wetting angle is carried out on the Easy Drop installation. After completion of a series of experiments consisting in the obligatory carrying out of three parallel measurements, the value ΔG _{S is} calculated by the equation ΔG _S = Δσ + σ · ln S _beats ^II / S _yd ^I. For the calculation, at least two converging experimental values of the contact angle are used. In addition, for each composite composition, the specific surface area of the system is determined. The obtained experimental results and calculated values of the isobaric-isothermal potential of the sand-saponite composite compositions are presented in table 1.

The invention is illustrated in the drawing, where Fig. 1 is a graphical view of the functional dependence ΔG _S = f (p), which shows the presence in the binary system under study of a region of the component ratio characterized by negative ΔG _S values.

Figure 2 and figure 3 presents the test reports of the modifier. In Fig.2, the ultimate shear resistance of a sample of sand fraction 0.1-0.25 mm without the addition of a modifier; figure 3 - with the addition of a modifier of 5% by weight.

Based on the foregoing, for this system, we can use the concept of thermodynamic compatibility of components, which is observed when the saponite content is in the range of 3–6%, and with a pronounced extremum with its 4% addition.

Indicators of the strength characteristics of the soil are specific adhesion and the angle of internal friction.

Examples of the invention, confirming the increase in the strength characteristics of sandy soil, are presented in table 2 - determination of specific adhesion and angle of internal friction (examples 1-6). The tests were carried out on a Shear Trac-II straight cut device.

The composition for strengthening obtained by mixing the crushed saponite-containing material and sand is added to the sandy soil in a dry state, followed by mixing.

The examples of the implementation of the invention 1-6 confirm the increase in the strength characteristics of sandy soil when using the inventive composition.

Claims (1)

A composition for strengthening sandy soil, comprising a filler and a binder component, characterized in that the filler contains sand (finely dispersed) (74-136 nm), and a saponite-containing material (265-451 nm), crushed to a microdispersed state (265-451 nm), isolated from the pulp of a tailing pond for industrial processing of ores from a diamond deposit, in the following ratio of components, wt.%:
saponite-containing material 3-6;
sand - the rest.

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