黄土地区高层建筑箱形基础的沉降分析

高层建筑采用箱形基础,施工时基坑开挖会挖去大量土体,引起地基土回弹,同时建筑荷载较大,控制基础沉降成为工程设计的关键问题之一。文中以西安小雁塔宾馆工程为依托,通过测量基坑土的回弹变形,基坑开挖和建筑物荷载对相邻地基土的变形影响以及地基土层的沉降量,分析了高层建筑箱形基础基坑开挖到建筑施工的不同阶段,基坑范围内及相邻地基土的沉降变形特征。结果表明,深基础基坑开挖引起的回弹变形约占最终沉降量的30%,且当建筑物加荷等于挖土卸荷时仍有沉降。基坑范围内地基土的沉降量远大于相邻地基土,经分析这种差异主要来源于基础边缘土体的剪切变形。

SETTLEMENT ANALYSIS OF HIGH-RISE BUILDING BOX FOUNDATION IN LOESS AREA

The box foundation is adopted in high-rise building. Excavation of foundation pit during construction will dig a large amount of soil, causing rebound of foundation soil. At the same time, the building load is large. Controlling the foundation settlement becomes one of the key problems in engineering design. Based on the Xiaoyan Pagoda Hotel in Xi'an, this paper analyzes the settlement deformation characteristics of the scope of the foundation pit and the adjacent foundation soil in the different stages from the excavation of box foundation pit to the construction of the building by measuring the rebound deformation of the foundation pit soil, the adjacent foundation deformation caused by the excavation and the load of the building and the settlement of the foundation soil. The results show that the rebound deformation caused by the excavation of deep foundation pit accounts for about 30% of the final settlement, and there is still settlement when the loading of the building equals to the unloading of excavation. The settlement of foundation soil in the scope of foundation pit is much larger than that of adjacent foundation soil. The difference is mainly due to the shear deformation of soil at the edge of foundation.