考虑结构应力粘土一维非线性固结分析.docVIP

考虑结构应力粘土一维非线性固结分析 　　摘 要：考虑结构性粘土的结构应力比以及施工荷载分级加载情况，建立了考虑结构应力比的天然饱和软粘土一维非线性固结控制方程，采用Crank-Nicolson有限差分格式对固结方程进行了求解，并与不考虑结构应力比的一维线性和非线性固结结果进行了比较分析，最后针对不同η/c比值分析了天然饱和软粘土的一维非线性固结性状。研究表明，非线性参数η/c对固结速率有较大影响，η/c值越小孔压消散越快，固结速率越大。在固结初始阶段不考虑结构应力比的线性与非线性固结计算结果比较接近，随着固结的发展，不考虑结构应力比的非线性固结由于未考虑粘土天然结构应力的存在高估了土体非线性的影响，而考虑结构应力比的非线性固结计算结果更接近于天然粘土的固结性状。 　　关键词：粘土；结构应力比；一维非线性固结；数值模拟 　　中图分类号：TU443 文献标志码：A 文章编号：1674-4764（2012）02-0039-07 　　 　　One-Dimensional Nonlinear Consolidation Analysis of Clay Considering Structural Stress 　　LIU Yang, GONG Zhi, WANG Zhe 　　(Civil and Environmental Engineering Institute, University of Science and Technology Beijing, Beijing 100083, P. R. China) 　　Abstract:One-dimensional nonlinear consolidation equations have been established taking into account the effect of structure stress ratio of natural clay and stepped time-dependent construction loading. Crank-Nicolson formula is adopted to solve these equations using the finite difference method. Numerical results are compared to those of linear and nonlinear consolidation taking no account of structure stress. Finally, effects of nonlinear parameter η/c on consolidation are analyzed, which indicates that consolidation rate increases with the decrease of η/c. Numerical results of considering structure stress or not are similar initially. With the development of consolidation, the nonlinear results of not considering the structure stress overestimate the effect of nonlinearity. 　　Key words:clay; structure stress ratio; one-dimensional nonlinear consolidation; numerical simulation 　　 　　一维非线性固结理论的研究始于20世纪60年代，早期如Davis和Raymond［1］基于线性的e-lgp关系，假设渗透系数kv与体积压缩系???mv是同步的，得出了固结系数cv为恒定量的固结方程，并且获得了解析解。Mesri［2］等和Barden［3］等根据试验得出e-lgp和e-lgkv经验关系，将其应用于饱和软土一维固结研究中。谢康和等［4-5］建立了逐步加荷条件下单层和双层地基一维非线性固结的解析解，并在以往研究的基础上推导了考虑了应力历史这一因素的一维非线性固结方程，其假定荷载为单级均布连续荷载，采用经验关系的e-lgp和e-lgkv非线性关系，未考虑天然土的结构性的影响。曹宇春等［6］建立了任意施工荷载下天然结构性粘土的一维非线性固结方程，但仍沿用e-lgp和e-lgkv的非线性关系。吴建等［7］同时考虑了固结过程中材料和几