基于上限理论的软土基坑抗隆起稳定分析方法

多块体上限法是当前岩土工程稳定性问题求解的一种严格、高效、简便且实用的方法。依据多块体上限法求解岩土工程稳定性问题的一般模式，通过对软黏土基坑抗隆起稳定性问题的适当简化，从而提出了基于极限分析上限理论的黏土基坑抗隆起稳定分析新方法。为适应国内外深基坑工程实践的现状，分别给出了土体强度指标为固结不排水剪及不固结不排水剪时的上限法理论方程中内能耗散项的计算方法。给出了所提出新方法求解实现的详细过程，并编制了该方法的计算程序，从而使所提出的方法能够直接应用于国内外的工程实践。详细分析总结了支护墙体刚度、支护墙体入土深度、基坑开挖深度、土体强度等影响因素对抗隆起稳定性的影响及规律，最后通过具体工程实例的计算及对比说明了该方法的合理性及实用性。

Basal stability analysis for excavations in soft clay based on upper bound method

The multi-block upper bound method is a good choice for the stability analysis problems in the geotechnical engineering.It is simple,highly effective and of rigorous theoretical basis.According to the usage process of the multi-block upper bound method,some simplifications are made for the basal stability analysis of braced cuts in clay.After the simplifications,a new method based on the upper bound method is proposed for the basal stability analysis,and the detailed calculation process is discussed.Considering different soil strength indices used in practice,the calculation methods for consolidated-undrained strength and unconsolidated-undrained strength are put forward respectively,and they can be used in practice at home and abroad.Several calculations are presented to analyze the effects of some important factors on the basal stability safety.Finally,a real excavation case is calculated and comparisons are made with the methods recommended in the codes to examine the proposed method.