A new understanding of limit theorem (Lower/Upper Bound Theorem) and its application to stability analysis

考虑不排水强度各向异性的影响，采用基于极限定理（上下界定理）的理论对各向异性固结黏土的承载力进行了分析。特别地，在本研究中，对极限定理进行了推广。这种理论的推广不需要假设“关联”流动规则。在此基础上，提出了一种寻找容许坍塌机制的新方法。用这种方法进行极限分析时，不需要专门的技术来寻找接近精确解的容许崩溃机制。该方法无需人工试验即可形成容许的坍塌机制。给出了不同类型剪切试验的承载力系数随Ko的变化规律。用该理论计算的承载力与试验结果吻合较好。在常规稳定性分析中引入强度各向异性和剪切速率的影响时，需要对剪切试验测得的不排水强度进行校正。利用现有理论对各种试验强度给出了强度各向异性的修正系数。

The bearing capacity of anisotropically consolidated clay is analyzed by the theory based on the limit theorem (Upper/Lower Bound Theorem) taking the effect of anisotropy of the undrained strength into account. Particularly, in this investigation, the limit theorem was generalized.This generalization of the theory does not require the assumption of 'associated' flow rule. And then A method to search such admissible collapse mechanism was newly developed in this investigation. The limit analysis using this new method does not require the special technique to search the admissible collapse mechanism which is close to the exact solution. This method can form the admissible collapse mechanism without any artificial trial.The variations of bearing capacity factors with Ko are given for various types of shear test. The bearing capacities calculated by the present theory show fairly good agreement with the experimental results. The undrained strength measured by shear tests should be corrected in connection with the strength anisotropy and the effect of shear rate when they are introduced in conventional stability analysis. The correction factors for strength anisotropy are given by using present theory for various kinds of test strength.