分层土中桩筏土共同作用近似三维分析  

Pile-soil-cap Interaction Analysis based on Three-dimensionally Elastic Theory in Layered Soils

作　　者：洪鑫 

机构地区：[1]江苏中大建设集团有限公司,江苏昆山215300

出　　处：《地下空间与工程学报》2016年第5期1239-1246,1314,共9页Chinese Journal of Underground Space and Engineering

摘　　要：基于变分原理,利用Mindlin位移解,通过将桩沿桩与土接触面、筏板沿与土接触面进行三维剖分,建立了在分层土中能够考虑桩筏土相互作用的三维分析方法,利用该方法能够考虑筏板侧壁摩阻效应、分层土、长短桩、不等直径桩的影响。与现有的方法相比,该方法能够更好地模拟桩身摩阻力沿桩身横截面的分布,从而使筏板下群桩之间被夸大的效应减小,桩顶荷载的分布更趋于实际。通过对一组案例进行分析,结果表明:(1)筏板侧壁摩阻效应仅对筏板的板底边缘应力分布影响较大,中部影响较小,对沉降的影响却较小;(2)分层土的位置对桩筏承载的影响较大,尤其是筏板底和桩端所在土层的影响尤为明显。An approximate three dimensional semi-analytical method is proposed in this paper to obtain the loadsettlement relationship of the pile groups,cap and soil interaction in layered soils,using the Mindlin＇s settlement equation and the static force equilibrium equation based on variational principle,both the pile-soil and the cap-soil interfaces are discretized. The proposed method can consider the effects of cap shaft,layered soils,long-short piles group and unequal diameter piles group. Comprised with the present methods,more agreeable results which can model the distribution of pile shaft stress along the cross section of pile and decrease pile group effect are obtained,consequently the distribution of pile head load is more agreeable with the facts than the existed methods. By calculating a case,the results show that the influence of the stress of cap bottom in the edge of cap is more obvious than the stress of cap bottom in the center of cap if the effect of cap shaft stress is considered,while the influence of settlement is less; the position of layered soils has more effects on the behavior of pile-soil-cap interaction,especially the position of some soil at cap bottom or pile group base.

关 键 词：桩筏土共同作用 变分法 MINDLIN位移解 三维弹性分析 分层土 

分 类 号：TU470[建筑科学—结构工程]