变刚度调平布桩模式下筏底地基土承载性状研究  

Bearing capacity behaviors of subsoil under optimal design mode of pile foundation stiffness to reduce differential settlement

作　　者：王涛[1] 

机构地区：[1]中国建筑科学研究院地基基础研究所,北京100013

出　　处：《岩土工程学报》2011年第7期1014-1021,共8页Chinese Journal of Geotechnical Engineering

基　　金：建设部科技项目(97-07-02);十一.五国家科技支撑计划课题(2006BAJ27B02)

摘　　要：针对桩基变刚度调平设计方法进行了现场大型模型试验和具体工程实测跟踪分析,测量了变刚度调平布桩模式下筏底地基土反力,对比模型试验和工程实测结果分析了不同荷载级别下桩土荷载传递特性和桩土荷载分担比规律。按变刚度调平原则进行设计的桩筏基础,主楼荷载向两侧裙房传递的范围约为裙房1.25跨左右,荷载扩散强度随裙房层数增多而增大。筏板边缘与中心点处土反力比值在1.89~1.23之间。相当于工作荷载时,筏板下地基土约分担总荷载的37.5%,并随荷载增大而提高。这说明变刚度调平设计将核心筒外围设计为复合桩基既合理又能有效地发挥桩和承台的承载作用,减小用桩量,还可最大限度减小差异沉降。Field model tests and engineering application case are performed on a pile foundation under the optimal design mode of pile foundation stiffness to reduce differential settlement.Raft-soil contact pressures are measured.Based on the analysis of the measured data,the load transfer mechanism and stress ratio of pile to soil under different load levels are summarized.For the pile raft foundation,the range of load transfering to the podium at both sides of the main building is about 1.25 times the span of the podium.The intensity of spreading the load increases with the increase of the number of podium layers.Raft-soil contact pressure ratio between the edge of the raft and the center of raft is 1.89~1.23.The soil under the raft distribution load ratio is 37.5% under the working load level.The ratio increases with the increasing load level.It shows that it is reasonable that the outside of the core tube is designed as a composite pile.The bearing capacities of the piles and the cap are effectively increased.The number of the piles is reduced,and the differential settlement is minimized.

关 键 词：桩基础 地基土反力 承台效应系数 变刚度调平设计 

分 类 号：TU44[建筑科学—岩土工程]