Evaluation of the Impermeability of a Curtain Formed from Alluvial Clayey Loams Based on Study of the Microstructure of the Soil and Filtration Investigations

Abstract

Results of complex investigations of the microstructure and filtration strength of alluvial clayey loams used for experimental backfilling of a curtain for the ash dump at the Ryazan’ state regional power plant are presented. It is demonstrated that clayey loams with a plasticity index of more than 0.10 dec. units can be layered in a curtain with the in situ moisture content and, moreover, should be mandatorily compacted to a state characterized by an average degree of saturation of 0.9. The permeability of the clayey loams compacted in this manner is diminished by tens of thousands of times with respect to the in situ structure. The clayey loams in the curtain are characterized by essentially homogeneous and a slightly oriented matrix microstructure, exhibit high impermeability, and take up pressure differentials of up to 400 with no internal displacement of soil particles.