Investigation on mechanical properties of structured soils subjected to axially loading-unloading under undrained conditions
HE Miao1，2，LIU Enlong1，2，CHEN Yajun3，TANG Yong1，2
(1. State Key Laboratory of Hydraulics and Mountain River Engineering，Sichuan University，Chengdu，Sichuan 610065，China；2. College of Water Resource and Hydropower，Sichuan University，Chengdu，Sichuan 610065，China；3. PowerChina Kunming Engineering Corporation Limited，Kunming，Yunnan 650000，China)
Abstract：To study the mechanical properties of structured soils under undrained conditions，the triaxial compression tests on reconstituted soils and two kinds of structured soils with initial stress-induced anisotropy and isotropy were carried out under axially loading-unloading-reloading. The soils were tested under consolidation- undrained(CU) conditions at the confining pressures of 25，50，100，200 and 400 kPa，and the results of tests are analyzed with the binary-medium theory. It is found that the structured soils have stronger structures at lower consolidation stress. Meanwhile，Eave does not change significantly in different stress cycles. When the confining pressures are higher，the structures of soils are weakened，and their characteristics are similar to those of reconstituted soils. Because of the structure weakening and positive pore pressure，Eave decreases with the increase of εa. With the increase of the axial strain，the breakage rate of the bonded components and the soil particle spacing of friction components increase. In the meantime，the tendency of the volume contraction becomes more apparent when unloading.
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2017, Vol. 36 
