K0固结条件下砂土的循环剪切特性试验研究

利用土工静力-动力液压三轴-扭转多功能剪切仪，针对福建标准砂Dr = 30 %，在K0固结条件下，进行不同围压下的循环三轴试验，探讨了K0固结过程和K0固结条件下砂土的孔隙水压力特性与强度特性，并与原有均等固结条件和非均等固结条件下的循环三轴试验进行对比分析。通过分析和比较表明，砂土的K0固结试验过程可以分为两个阶段，第1个阶段是初期的缓慢变形阶段，第2个阶段是后期的稳定发展阶段，围压对静止土压力系数K0的测定有一定影响。不同固结过程对砂土动孔隙水压力的发展有很大的影响，K0固结条件下试样出现明显的剪胀现象。另外，K0固结条件下砂土动强度高于非均等固结条件（Kc = 1.67）下砂土动强度，低于非均等固结条件（Kc =2.94）下砂土动强度。

Experimental studies of cyclic shear characteristic of sand under K0 consolidation condition

Using the soil static and dynamic universal triaxial and torsional shear apparatus, a series of cyclic triaxial shear tests under different confining pressures are performed for saturated Fujian standard sands with a relative density of 30 % under K0-consolidation condition. And compared with the cyclic triaxial tests under both isotropic and anisotropic consolidation conditions, the procedure of K0 consolidation and the cyclic shear characteristic of sand under different consolidation conditions are discussed. The procedure of K0 consolidation includes two stages: the gradual deformation stage and the steady deformation stage. The measure of the coefficient of earth pressure at rest K0 is affected lightly by different confining pressures. And the development of the pore-water pressure under different consolidation conditions is different. The dynamic strength of sand under K0 consolidation condition is higher than the dynamic strength under anisotropic consolidation conditions (Kc=1.67) and lower than the dynamic strength under anisotropic consolidation condition (Kc =2.94).