柔性和刚性浅基础的地基承载能力分析

Analysis of bearing capacity of subsoil under flexible and rigid shallow foundations

为了研究刚性和柔性加载面下地基的破坏机制和极限承载力,着重对比分析了不考虑土体自重条件下柔性基础、基底完全光滑或完全粗糙的刚性基础的地基,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。通过对这3种基础类型下地基的计算结果的对比分析,并结合国内外模型试验成果,得到如下结论:柔性和刚性浅基础地基在不考虑土体自重的条件下有相近的地基极限承载力,但基底水平面上竖向应力和位移的发展规律、临塑荷载及滑动面有着明显的区别。

In order to study the failure mechanism and ultimate bearing capacity of weightless subsoil under rigid and flexible foundations, comparative studies are conducted for flexible foundation, rigid rough foundation and rigid smooth foundation in the case that the effect of soil dead-weight was negligible. Mohr-Coulomb inside-tangent circle yield criterion under associated flow rule was adopted. The ultimate failure state of subsoil from linear elasticity to plasticity gradually was modeled by incremental elastoplastic FEM. Some conclusions are drawn from computational results of three kinds of foundations mentioned above and model test results in the literature. It is shown that the weightless subsoil under rigid and flexible foundations have similar ultimate beating capacity; while development trends of vertical stress and displacement, critical edge pressures and slip surfaces are obviously different.