中国国际丝路中心大厦地下室结构设计

竖向荷载引起的地基总沉降及差异沉降是超高层结构设计中需重点考虑的技术难点。为提高基础刚度，减小差异沉降以及提高底板抗冲切承载能力，除基础能直接支承在基岩上的情况外，国内高度500 m左右的超高层均布置有地下室翼墙。中国国际丝路中心大厦建筑高度498 m，地上101层，地下4层，是否布置翼墙成为地下室设计的重点。针对该项目建筑平面布局，布置翼墙会严重影响地下室使用功能；同时，翼墙本身工程造价大且施工复杂。为此，对比分析了翼墙布置与否的两种模型的自振周期及位移角等指标差异，研究了翼墙开洞与否以及不布置翼墙三种情况下不同桩长方案对底板差异沉降的影响，验算了不布置翼墙情况下底板抗冲切及受弯承载力，并分析了上部结构收缩徐变、底板长期刚度折减对底板影响以及底板变形对核心筒内力影响。结果表明：设置地下室翼墙对结构整体指标影响很小；不布置翼墙，通过调整外框部分桩长，可以使底板差异沉降、底板及核心筒墙承载力均满足要求。为此，该项目未布置地下室翼墙具有可行性，且经济合理。

Basement structure design of China International Silk Road Center

The total and differential settlement of foundation caused by vertical loads is one of the key points in design of super high-rise structure. In order to improve the foundation stiffness, reduce differential settlement and improve punching bearing capacity of the mat foundation, in addition to the situation that the foundation is directly supported on bedrock, domestic super high-rise buildings with a height of about 500 m are equipped with reinforced concrete fin walls in basement. The height of China International Silk Road Center is 498 m, with 101 floors above ground and 4 floors below ground. According to layout of this project, fin walls will seriously affect functionality of the basement. At the same time, the engineering cost of fin walls is large and the construction is complex. For this reason, the natural vibration period and story drifts of two models with or without fin walls were compared and analyzed. At the situation where fin walls were included while there were openings on fin walls or not, and the situation where fin walls were excluded, the influence of different pile length schemes on the differential settlement of foundation was studied. The punching and bending bearing capacity of the foundation were checked with fin walls cancelled. The influence of shrinkage and creep of the upper structure and reduction of foundation stiffness due to long-term effect on foundation, and the influence of the deformation of foundation on internal force of core walls were also analyzed. The results show that fin walls have little influence on overall performance of the structure. Without fin walls, by adjusting the length of piles of the outer frame, the settlement difference of foundation and the bearing capacity of both the foundation and core walls can meet requirements. So it is feasible and economic to cancel the basement fin walls.