厚层黏性土地基上某超高层建筑桩筏基础三维数值分析

Three-dimensional numerical analysis on piled raft foundation of a super high-rise building on the thick-layer clay foundation

工程位于北京市大望京地区,由一栋200m高超高层办公楼、配套裙房及纯地下室组成。采用桩筏基础,地基为北京东北区域典型厚层黏性土,本区域地层有别于北京城区的黏土层与砂卵石层交互循回沉积层,厚层黏性土地基对建筑变形影响较大。基于地基-基础-上部结构的共同作用原理,利用岩土工程数值软件PLAXIS 3D对两种沉降后浇带设置方案进行桩筏基础沉降计算分析,结合施工的便捷性和工程的经济性,选择较合适的沉降后浇带设置方案。并对所选方案进行沉降后浇带封闭前的基础沉降、基础底板内力、基底反力及桩顶反力计算分析,证实了所选方案的可靠性。

The project is located in Greater Wangjing area in Beijing and is composed of a 200 m high super high-rise office building,matching podiums and basements. Piled raft foundation is applied on the typical thick-layer clay of northeast region of Beijing. The regional strata is different from the clay and sandy pebble layer interaction cycle back to sediments of Beijing city,and such geological conditions impact the building deformation a lot. Based on the interaction principle of soilfoundation-upper structure,the piled raft foundation settlements based on two different post-pouring settlement strip schemes were calculated and analyzed by using the geotechnical engineering numerical simulation software of PLAXIS 3D.Considering with the construction convenience and economy,the better scheme was chosen. The parameters of the chosen scheme before post-pouring strip construction were analyzed and calculated,including foundation settlement,internal forces of foundation base,base reaction and the pile top forces,which verified the reliability of the chosen scheme.