V-M荷载作用下双层黏土地基破坏包络线研究

Failure envelopes for eccentrically loaded surface strip footings on undrained two-layered clays

地基破坏包络线的研究是复合加载模式下地基承载力设计的关键。根据建立的数值计算模型,用Abaqus商业软件分析了V-M荷载作用下,位于双层黏土地基上条形基础的破坏包络线随上层土厚度比、土层强度比的变化规律,以及地基破坏模式随荷载偏心率的变化趋势。用有效面积概念将传统竖向极限承载力换算为V-M荷载平面的破坏包络线,与数值计算结果进行对比。结果表明,公式换算方法适用于均质黏土地基,而对双层黏土地基偏于保守。

The predicting of failure envelopes of foundations under combined loading is a key issue for bearing capacity design. In this paper, based on the assumption that the contact between the footings and clay is unable to sustain tension, a two-dimensional finite element model for strip footings on two-layered clays is established. Parameter studies are performed using Abaqus software in vertical （V） and moment （M） loading space, and gain the failure loci and some of its features. The failure loci scaled from the traditional bearing capacity formula using an effective method is compared with FEM result. The FEM result may form the basis of bearing capacity design. The scaling method only pertains to homogeneous foundation, but underestimates the bearing capacity of two-layered clay foundation.