中低压缩性地基上设置沉降后浇带的主裙楼沉降及基底反力分布特征

Settlement and contact pressure characteristics of the main building and annex with post-cast strips on medium or low compressible soil

沉降后浇带是经常采用的主裙楼连接方式,设置沉降后浇带的大底盘高层建筑共同作用分析更复杂。介绍了设置沉降后浇带的大底盘高层建筑的共同作用分析方法:按施工过程中的不同工况分别计算,然后将计算结果叠加;采用有限压缩层地基模型,并考虑回弹再压缩;考虑上部结构刚度分段形成。对于中低压缩性地基上的主裙楼结构,通过对简化模型进行计算分析,得到了不同沉降后浇带设置位置、不同后浇带浇筑时间条件下的沉降、基底反力分布特征:后浇带封闭时间越晚,主裙楼连接处在封闭后产生的差异沉降越小,但主楼最大沉降会增加;与后浇带设置在主楼外第1跨相比较,后浇带设置在主楼外第2跨时,主楼最大沉降减少,主裙楼连接处的差异沉降减小,主楼下平均地基反力降低。

Post-cast strips are widely used in the main building and annex, and the interaction analysis is more complicated. The interaction analysis method for the main building and annex with post-cast strips is introduced. Calculation should be done separately according to different working conditions during construction, and the calculation results should be added together. The limited compression layer model is used as the foundation model, and both resilience and recompression are considered. The structure stiffness is formed step by step. For the main building with annex on medium or low compressible soil, by analyzing simplified models with different locations of post-cast strips and different pouring time, the settlement and contact pressure show the feature as follow: the later post-cast strips are poured, the smaller the differential settlement between the main building and the annex is, but the settlement of the main building is larger; compared with post-cast strips at the first span outside the main building, both the maximum settlement of the main building and the differential settlement between the main building and the annex are decreased, and the average contact pressure under the main building is lower, when the post-cast strips are set at the second span outside the main building.