STUDY OF DILATANCY EFFECT OF REDSTONE COARSE GRAINED SOIL BY LARGE SACLE TRIAXIAL TESTS
CHEN Xiaobin1，2
(1. Department of Civil Engineering，Central South University，Changsha，Hunan 410075，China；2. National Engineering Laboratory of High Railway Construction Technique，Central South University，Changsha，Hunan 410075，China)
Abstract：In order to study the dilatancy effect of granular soil and effects on the dilatancy tendency under different confining pressure conditions，a series of red stone granular soils tests are executed by the large scale triaxial shearing apparatus. The test results show that the confining pressure has obvious effects on the dilatancy effect of granular soil，and the different dilatancy effects are observed from the different confining pressure tests. When the confining pressure is less than 200 kPa，the ratio of volume increment to axial strain(dev/de1) is negative，which shows dilatancy tendency. When the confining pressure exceed 400 kPa，the ratio of volume increment to axial strain(dev/de1) is positive，and the red stone granular soil samples shows shearing shrinkage tendency in the tests. The red stone granular soil dilatancy tendency is also changed by the axial strain increment，with firstly quick dilatancy tendency and then slow dilatancy tendency. The coefficient K of Rowe shearing dilatancy model is obviously discrete during the shearing procedure，which reflects the deformation incompatibility between the coarse grains and fine grains in red stone granular soil. The discrete degree is minishing with the total axial strain increment. The shearing dilatancy coefficient K of Rowe is identified as 20–25 for the red stone granular soil in these test data.
