条形浅基础下无重土地基承载力研究

Research of Weightless Subsoil Bearing Capacity under Stripe Shallow Foundation

目的研究基础刚度对无重度均质地基的破坏机理和极限承载力的影响.方法采用关联流动的Mohr-Coulomb内切圆屈服准则,通过增量加载的有限元方法,全程模拟了地基由初始的线弹性状态逐渐过渡到塑性流动的极限破坏状态的过程.对照国内外模型试验成果.对3种基础类型下地基的计算结果进行对比分析.结果得到了各种屈服准则下的Nc,柔性基础、刚性基础下地基的Nc及等效塑性应变曲线、临塑状态水平位移曲线及位移矢量图.结论采用关联流动的Mohr-Coulomb内切圆屈服准则可以得到较为准确的条形浅基础的地基承载力;柔性基础与刚性基础的Nc的差别随着内摩擦角增大而增大;第一条裂缝出现的位置及特征均存在较大区别.

In order to study the influence of stiffness on the mechanism of failure and ultimate bearing capacity of weightless and homogeneous subsoil. Mohr-Couiomb inscribed circle yield criterion and associated flow rule are adopted. The overall process of subsoil from elasticity to plasticity gradually is modeled by elastoplastic FEM through load increment method. Computed results of three sort of foundation mentioned above are compared and integrated with some important results of model test, some significant conclusions can be obtained. The relativly accurate subsoil bearing capacity of stripe shallow foundation can be calculated by adopting Mohr- Coulomb inscribed circle yield criterion and associated flow rule. The difference of Nc between flexible foundation model and rigid foundation model increases with the angle of frictional resistance accretion.Both the location and the character of the first crack are qiute different.