基于三种强度准则下地基承载力的计算

现行地基承载力计算公式未考虑中主应力的影响,也未考虑侧压力系数K0的影响。基于平面强度理论,推导出SMP、Lade、M-C三大强度准则的统一表达式,进而推导出基于统一表达式的考虑K0变化的塑性界面方程,详细对比了三大准则在考虑K0及不考虑K0时塑性界面的特性。研究了内摩擦角、黏聚力及超固结度对于临塑、临界荷载的影响。结果表明:现规范采用的方法计算的临界荷载与同时考虑中主应力和K0变化的SMP准则得到的结果仅在内摩擦角较小时计算结果类似。临界荷载和临塑荷载随着内摩擦角或黏聚力的增大而增大。超固结度对于临塑荷载的影响很小,但对于临界荷载影响较大,且随着内摩擦角的增大而增大。

THE CALCULATION OF THE BEARING CAPACITY OF FOUNDATION BASED ON THREE STRENGTH CRITERIA

Based on the plane strength theory,the unified equation of the Mohr-Coulomb,SMP,and Lade-Duncan was derived,and the new plastic interface equation taking auount of coefficient of lateral pressure also was derived by the unified formula.The difference of plastic interface of the three failure criteria was researched.Also the effects of internal friction angle,cohesion and over consolidation ratio on the plastic load and the critical load were researched.The results of plastic and critical load by using the M-C failure criterion were similar with the results by using SMP failure criterion which considered the impact of the K0 and intermediate principal stress only if the internal friction angle was small.The results showed plastic and critical load would increase by increasing the internal friction angle or cohesion.Similarly,The results of the plastic load by considering the over consolidation ratio or not were almost consistent,but the OCR had a great influence on the critical load.