抄録
It is well established that the main mechanism for the occurrence of liquefaction under seismic loading conditions is the generation of excess pore water pressure. The growth of the excess pore water pressure of saturated sand is dependent on several factors. Changing the inclination and magnitude of the major principal stress with respect to the depositional direction in most cases will increase the collapse potential and brittleness as well as reduce the shear strength and shear stiffness. An experimental program was carried out to study the variation of pore water pressure of cross-anisotropic deposits under anisotropic cyclic loading. A total of 30 undrained cyclic tests were performed at a constant mean confining stress, σ0m, constant intermediate principal stress ratios, as indicated by b= (σ2-σ3)/(σ1-σ3), and principal stress directions, α. The experiments were performed on hollow cylinder specimens prepared by moist under compaction technique; with a height of 20cm, outer diameter of 10cm, and a wall thickness of 2cm. The applicability of an empirical model for predicting pore water pressure generation in clean sand during anisotropic cyclic loading has been studied. Results showed that inclination of the major principal stress with respect to the depositional direction had no significant effect on the residual pore water pressure. The residual pore water pressure was increased by increasing b parameter and confining stress. Moreover, increases of confining stress increased the effects of stress anisotropy on the excess pore water.
