上硬下软型地基强度和变形特性研究

Strength and Stability Analysis of the Double-Layer Subgrade with Rigid Upper and Soft Lower

通过对工程实例的有限元分析,研究了有软弱下卧层的双层体系地基的应力和变形特性.计算结果表明,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.为区域性多层建筑基础设计中更好的把握软土强度和变形特性提供一种有效的分析方法,对特定条件下的地基评价具有理论和现实意义.

In this paper, the stress and deformation properties of a double-layer subgrade with a soft under layer are studied in terms of FEM. The results indicate that the plastic zone of subgrade appears in the upper layer soil of the interface, and then, it expands to the interface and Both upper and lower layer with the increase of load, as the lower layer soil is soft, the plastic zone expands rapidly. Finally, when the plastic zone reaches the foundation bottom, the subgrade reaches its ultimate bearing capacity. According to the foundation design for the regional multi-storey buildings, this research provides an effective analytical method for a better understanding to the soft soil strength and deformation characteristics. The results serve the engineering design as references.