上硬下软双层地基有限元分析

在工程建设中经常遇见上层坚硬下层软弱的双层地基,本文利用大型有限元分析软件ANSYS对这一类的地基进行了弹性和弹塑性分析.从有限元的计算结果可以看出,地基中塑性区首先出现在交界面处的上层土中,随着荷载的增加,塑性区向交界面处上下土层均有扩展,由于下层土较软,塑性区扩展较快,最后当塑性区到达基础底面时,地基达到极限承载力,计算开始不收敛.本文揭示了该类地基在荷载作用下,地基中塑性区的产生和发展规律,可供工程设计人员参考.

Analysis of the Double-layer Sub-grade with Rigid Upper Layer and Soft Lower Layer by FEM

The double layer subgrade with rigid upper layer and soft lower layer is common in engineering construction. In this paper, the elastic and elasto-plastic analysis on such subgrade by ANSYS was carried out. According to the calculation results of FEM, the plastic zone of subgrade would appear in the upper layer soil of interface, then, it would be expanded up and down with increase of the load. As for the lower layer soil is relatively soft, the plastic zone is expanding rapidly. Finally, as the plastic zone reaches the bottom and the subgrade in the state of ultimate bearing capacity, the calculation starts to be non-convergent. The results can serve as reference to the engineering designers.