关键词: 花岗岩残积土, 常规三轴试验, 固结不排水试验, 抗剪强度

Abstract: For weathered granite residual soil obtained from Youxi county of Fujian Province, the remodeled soil samples with three dry densities of 1.73, 1.64 and 1.56 g/cm3 were prepared separately. 12 conventional triaxial consolidated undrained shear tests were carried out in the 3 dry density groups with confining pressures of 100, 200, 300 and 400kPa, respectively. The results show that: 1) the deviational stressaxial strain curves under different dry density conditions show a strain hardening trend. When the dry density remains unchanged, the deviational stresses increase with the increasing of confining pressure and dry density. The greater the confining pressure is, the steeper the deviational stress rising presents as axial strain developing, and the deviational stress increasing trend gradually approaches stable as the axial strain further increasing. 2) Pore pressure increases non-linearly with the increase of axial strain at firstly, and then decreases slightly or remains stable after reaching the peak value; Under the same confining pressure level with the higher the dry density being, soil sample presents the smaller peak pore pressure. 3) Under the condition of the same dry density, as the confining pressure increases the stress ratio q/p，of soil sample decreases, and the decreasing range gradually converges with the increasing of confining pressure. The final stress ratio under low confining pressure is slightly higher than that under high confining pressure level. The stress ratio q/p, increases with the increasing of dry density under constant confining pressure condition. When the axial strain reaches about 30%, the stress ratio basically reaches a stable state. 4) The shear strength of soil is closely related to dry density. The internal friction angle and cohesion of soil under CU condition increase with the increasing of dry density, and the effective internal friction angle and effective cohesion also increase with the increasing of dry density. Under the condition of the same dry density, the effective cohesion is slightly greater than the cohesion under CU status, and the effective internal friction angle is slightly greater than the internal friction under CU condition.

Key words: Weathered Granite Residual Soil, Conventional Triaxial Test, Consolidated Undrained Test, Shearing Strength