复合地基承载特性的弹塑性分析

对桩及承台采用线弹性有限元模型,对承台下桩周土采用弹塑性有限元模型,对群桩以外的土体采用线弹性无限元模型,在桩土接触面上设置接触面单元,利用三维弹塑性有限元对桩%D土%D承台相互作用进行了分析。得出了如下结论 :承台下桩顶反力总体表现出角桩最大,边桩次之,中桩最小的分布规律,随着作用在承台上的荷载增大,桩顶反力趋于均匀分布,承台下桩侧摩阻力是由桩端向桩顶逐渐发展的,承台对桩上部侧摩擦阻力存在“削弱作用”。为了验证本文方法的可行性,对承台下有九桩的情况进行了静载试验,将试验结果与本文计算结果进行了比较。

ELASTIC-PLASTIC ANALYSIS ON BEARING LOAD CHARACTERISTICS ON COMPOSITE

Using linear elastic finite element model for piles and pile cap, elastic-plastic finite element model for piles-surrounding soil under pile cap, linear elastic infinite element model for soil around pile group, and mounting interface element on the pile-soil interfaces, 3-D elastic-plastic finite element method is used to analyzing the pile-soil-cap interaction. It is found that under pile cap, the distribution law of the pile-top load is behaves as follow: the load exerted to the corner piles is largest to the side piles next, and to the middle pile lowest. The pile-top loads are uniformly distributed along with increasing load exerted on the pile cap, the skin friction of piles gradually develops from the pile-end towards the pile-top. The pile cap has a weakening effect on the skin friction of piles upside. To verify the results, a static load test on a nine pile group under pile cap performed. It is found that the obtained results from the proposed are matched for the results of the experimental test.