连续排水边界条件下饱和软土一维大变形固结解析解

Analytical solution for one-dimensional large strain consolidation of saturated soft soils with continuous drainage boundary

基于XIE等提出的饱和软土一维大变形固结的假设,通过引入连续排水边界条件研究瞬时荷载下饱和软土的一维大变形固结问题。利用变量代换、分离变量法和Laplace变换得到连续排水边界条件下饱和软土一维大变形固结解析解,通过退化解析解和有限差分数值解对比分析,对该解析解的正确性进行验证。基于所得解析解,分析土体的界面参数及荷载参数对土体一维大变形固结性状的影响。研究结果表明:界面参数α和β越大,土体的透水性越好,超孔隙水压力消散越快,地基的固结速度越快;当界面参数增大到一定程度后,连续排水边界可退化为完全排水边界;连续排水边界下以孔压定义的固结度Up随荷载参数λq的增大而减小,以沉降定义的固结度Us则随荷载参数λq的增大而增大;对比土体的界面参数和荷载参数对土体大变形固结的影响可知,界面参数对土体固结的影响更大。

Based on the assumptions of one-dimensional large strain consolidation proposed by XIE et al,the onedimensional large strain consolidation problems of saturated soft soils under instant loading were investigated by introducing the continuous drainage boundary.An analytical solution of one-dimensional large strain consolidation of saturated soft soils with continuous drainage boundary was obtained by using variable substitution,the separation variable method and Laplace transformation.The correctness of the analytical solution was verified by the comparison of degenerated analytical solution and finite difference numerical solution.Based on the analytical solution,the influences of interface parameters and loading parameters of the soils on the one-dimensional large strain consolidation behaviors of soils were analyzed.The results show that the larger the interface parameters(α and β)of the soils,the better the water permeability of the soils,the faster the dissipation of the excess pore water pressure,and the faster the consolidation speed of the soils;when the interface parameters increase to a certain extent,the continuous drainage boundary can be degraded to complete drainage boundary.The consolidation degree Updefined by the pore water pressure with the continuous drainage boundary decreases with the increase of the loading parameters λq,and the consolidation degree Usdefined by the settlement increases with the increase of the loading parameters λq values.Comparing the influence of interface parameters and loading parameters of the soils on the large strain consolidation of saturated soft soils,the interface parameters have greater influence on the consolidation of saturated soft soils.