饱和黄土动态液化和静态液化机理的差异性研究

饱和黄土在不同外荷载作用下其液化机理具有显著差异.为研究饱和黄土动态液化和静态液化机理的差异性,基于室内动三轴试验和静三轴试验,研究岷县永光饱和黄土动态液化后的动应力与轴向动应变关系、动孔隙水压力比与轴向动应变关系,分析其静态液化后的偏应力与轴向应变关系、孔隙水压力比与轴向应变关系,并结合液化前、后的SEM试验结果,研...

Difference between dynamic and static liquefactionmechanisms of saturated loess

The liquefaction mechanism of saturated loess varies significantly under different external loads.To study the difference between dynamic and static liquefaction mechanisms of saturated loess,a series of dynamic and static triaxial tests were conducted.The relationship between dynamic stress and dynamic strain,dynamic pore water pressure ratio and dynamic strain of saturated loess in Yongguang Village,Minxian County after dynamic liquefaction were analyzed.The relationship between deviatoric stress and axial strain,pore water pressure ratio and axial strain of the saturated loess after static liquefaction were also discussed.Based on the SEM test results before and after liquefaction,the effects of dynamic and static liquefaction on the structural characteristics of saturated loess were studied,and the difference of the two liquefaction mechanisms was discussed.The results showed that under cyclic dynamic loading,the strength of loess skeleton gradually loses and the pore deformation develops,resulting in the rise of pore water pressure until the dynamic liquefaction with flow slip characteristics occurs.However,under monotonic static load,the overhead pores in the loess are gradually compressed,and the soil particles falling into the pores are rearranged and combined,resulting in the increase of pore water pressure until static liquefaction occurs.Compared with static liquefaction,the apparent pore area of saturated loess after dynamic liquefaction is smaller,the pore uniformity is better,the pore arrangement is more disordered,and the pore structure is more complex.The difference between the two liquefaction mechanisms is mainly manifested in different growth modes of pore water pressure caused by the difference of meso-structure change process under different loads.The results may provide a theoretical basis for the prevention and control of liquefaction in loess area.