Yi Li | Keneng Zhang | Huihua Hu | Shicheng Nie
OPEN ACCESS
Sand grain mucky soil is a type of lacustrine sedimentary soft soil of Dongting Lake with a modest layer of silty fine sand in between. It has an unique structure of thin sand layer. In order to study the microstructure particularity of sand grain mucky soil, the paper selects the other three types of Dongting Lake soil as comparison, and collects parameters of equivalent diameter, average roundness, average shape factor and directionality of structure unit body by examining the undisturbed samples and samples under different consolidation pressure of the four types of soil with the use of scanning electron microscope, as well as picture processing technology and mathematical model. At the same time, the paper analyzes relations between surface void ratio, consolidation pressure, and probability entropy and permeability coefficient. The result of the study shows: 1) the main microstructure of sand grain mucky soil is laminated structure; 2) compared with other three types of soil, as consolidation pressure increased, the growth of equivalent diameter of sand grain mucky soil is the fastest in the early stage while slowing down significantly in the later stage, the decreasing range of average roundness is the most, and changes of average shape factor and directionality are the smallest; 3) the effect of different consolidation pressure on surface void ration of sand grain mucky soil is relatively small; 4) the kH and kV of sand grain mucky soil decline as probability entropy decreased, and k-Hm curves of horizontal section and vertical section have big differences due to the modest layer of silty fine sand.
Sand grain mucky, Physical and mechanical properties, Soil microstructure types, Microscopic parameters
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