考虑起始水力坡降的软土一维非线性固结分析

Analysis of one-dimensional nonlinear consolidation for soft soils with threshold gradient

建立了考虑起始水力坡降的软土非线性固结控制方程,利用有限差分法求取其数值解答,通过与达西定律下的解析解相对比验证了数值计算的可靠性.在此基础上,分析了不同参数对固结性状的影响,研究结果表明:起始水力坡降越大,渗流前锋至土层底面所需要的时间越长,超静孔隙水压力的消散速率越慢;cc/ck值越大,渗流前锋移动速率越慢,土层的固结速率也就越慢;渗流前锋的移动速率随着荷载的增大及土层厚度的减薄而加快;cc/ck=0.5时,土层固结速率随着荷载的增大、土层减薄而逐渐加快;cc/ck=1.5时,土层固结速率随着荷载的增大、土层减薄而逐渐减慢.

With the considerations of threshold gradient and nonlinearity,the governing equation was established,and the numerical solutions was solved by finite difference method and verified by comparing with analytical solutions from Darcy＇s law.The influence of parameters on consolidation behavior was discussed.The results show that the time of seepage boundary moving to the bottom surface of soil layer is increased with the increasing of threshold gradient,while the dissipation rate of excess pore water pressure slows down.With the increasing of cc/ ckvalue,the moving rate of seepage boundary and the rate of consolidation both slow down.The moving rate of boundary speeds up with the increasing of the external loading or decreasing of soil layer thickness.The consolidation rate of soil layer speeds up with the increasing of external loading or with the decreasing of soil layer thickness for cc/ ckof 0.5.The consolidation rate of soil layer slows down with the increasing of external loading or with the decreasing of soil layer thickness for cc/ ckof 1.5.