Method for improving expansive soil by means of coal ash

Abstract

The invention relates to a method for improving expansive soil by means of coal ash. According to the method, the coal ash is added into the expansive soil, wherein the mass of the coal ash added intothe expansive soil is 20% of that of the expansive soil; the coal ash is an additive for effectively improving the expansive soil, the coal ash is mixed with the expansive soil, an ion exchange effect and pozzolanic reaction exist, and the swell-shrink effect of the expansive soil can be reduced; after the coal ash and the expansive soil are mixed, the coal ash can interact with a soil body undera certain water content condition, the ion exchange effect (high-valence cations in the coal ash replace low-valence cations in the expansive soil) is generated, the plasticity index, the activity index, the swell-shrink characteristic and the like of the expansive soil can be effectively decreased or reduced, and aggregate, containing the fine-grained components, in the soil is made to have relatively-coarse-grained components; the high-valence ions capable of being used for having the ion exchange effect in the coal ash, namely Ca2<+>, Al3<+>, Fe3<+> and the like, can promote flocculation of clay particles; and the coal ash contains a certain amount of amorphous SiO2 and Al2O3, and pozzolanic reaction can occur when the coal ash interacts with the soil.

Description

technical field [0001] The invention relates to the field of geotechnical engineering, in particular to a method for improving expansive soil with fly ash. Background technique [0002] Expansive soil is a geological body with many cracks and significant expansion and contraction formed in the natural geological process. Expansive soils are widely distributed in my country, and their clay components are mainly composed of strongly hydrophilic minerals montmorillonite and illite. The property of expansive soil to absorb water, expand, lose water, shrink and deform repeatedly, and its chaotically distributed cracks inside have serious damage to engineering buildings, especially light buildings, roadbeds, cutting slopes, etc., and the deformation of buildings Destructive effects have long-term potential hazards. Excessive deformation is due to the change in the volume of the expansive soil foundation due to the change in water content, which causes damage to the structures on...

AI Technical Summary

Problems solved by technology

[0005] Aiming at the deficiencies of the prior art, the present invention provides a method for improving expansive soil with fly ash that changes the strong hydrophilicity of expansive soil minerals, improves its physical and mechanical properties, and fundamentally solves the engineering problems of expansive soils.

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