Evolution mechanism of dry-wet cycle fracture in expansive soil under action of iron ion
In order to investigate the mechanism of dry and wet cycle fracture evolution of swelling soils under the action of Fe3+,saturated swelling soils contaminated by different concentrations of Fe2(SO4)3 solution were subjected to dry and wet cycle fracture tests,scanning electron microscopy(SEM)tests and X-ray diffraction(XRD)tests to investigate the evolution of dry and wet cycle fracture,microstructure and mineral composition of swelling soils under the action of Fe3+.The results show that under the same dry and wet times,the soil fracture area rate decreases when the Fe3+ concentration increases;when the dry and wet times increase,the soil fracture area rate of the same Fe3+ concentration increases in general;after the contamination of Fe3+ solu-tion,the intergranular pore fluctuation changes slightly,the clay mineral crystal structure is damaged and the crystal layer spacing decreases;after the dry and wet action,the intergranular pore space increases dramatically,the soil structure is damaged and the crystal damage is intensified.Comprehensive experimental results and analysis conclude that the mechanism of dry and wet cycle fracture evolution of swelling soil under the action of Fe3+ is as follows:water molecules repeatedly migrate in the soil body,deteri-orate the soil structure,form tensile stress and lead to fracture generation;Fe3+,on the other hand,reduces particle space to a cer-tain extent,enhances tensile strength,reduces tensile stress and inhibits fracture development.
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万方数据
维普
