分层土中桩筏基础荷载分担问题的有限元分析

Analysis of the Load Ratio of Piled Raft Foundation in Layered Soil Using Finite Element Method

采用三维有限元方法建立桩筏基础模型来考虑各种影响因素对桩土分担比的影响。地表硬壳层的存在能够有效地提高筏板的分担作用。通过对不同桩距和布桩方式桩筏基础的计算,发现当桩距径比增大时,桩间土的承载作用有显著提高,但当大于7d之后则无显著变化。此外,还研究了不同桩端土的相对刚度以及应力水平下桩筏基础共同作用性状,可供工程设计人员参考,以优化设计并满足较高的经济性。

This paper discussed the effect of various factors on the load distribution between piles and raft in piled raft foundation by using 3D finite element method. The existence of a relatively hard layer just below the raft can remarkably enhance the load bearing action of raft. Through numerical calculation of piled raft foundation with several different s/d and arrangements of piles, it was found that the load bearing action of the soil surrounded by piles wouldn't stop increasing evidently until distance between piles exceeded 7d. In addition, efforts have been made on the analysis of the behavior of piled raft foundation with different relative stiffness of soil at the level of pile tip and various stress level. The results may be helpful for engineering designers as a reference to refine or optimize the design plan.