基坑支护利用主体结构柱构成体系进行换(拆)撑的应用

The system of main structure column is used to replace(dismantle)braces in foundation pit support

地下室根据后浇带分布采取分区施工,导致某些拆撑部位底板完成但主体楼板(待拆撑梁下)未完成,只依靠底板进行应力传递无法控制桩顶水平变形,此时可考虑利用主体结构柱构成体系进行换(拆)撑的方法,从设计思路、计算和监测等方面进行了系统分析,得出以下结论:1)在实际施工过程中,地下室会根据后浇带的分布采取分区施工,导致某些拆撑部位底板完成但主体楼板(待拆撑梁下)未完成,不能常规利用楼板换(拆)撑,可考虑利用主体结构柱构成体系进行换(拆)撑的方法。2)利用主体结构柱构成体系刚度有限,需结合待换(拆)撑区域的应力大小及周边变形要求合理利用主体结构柱数量,保证应力转移所需的体系刚度。3)一般情况下,利用主体结构柱重新构成的体系刚度小于整体楼板刚度,计算模型中可适当减小支撑刚度(取整体楼板刚度75%),通过该实例,该计算模型可应用于实际工程并取得了较好的效果。

according to the distribution of the post-cast zone,the subarea construction of the basement leads to the completion of the bottom plate of some supporting parts but not the main floor(under the supporting beam to be dismantled),and the horizontal deformation of the pile top can not be controlled only by the stress transfer of the bottom plate,at this time,the method of replacing(disassembling)the braces by the system of the main structural columns is considered,and the systematic analysis is carried out from the aspects of the design idea,calculation and monitoring,etc.,the basement will be divided into sections according to the distribution of the post-cast bands,which results in the completion of the bottom slab in some parts of the bracing,but the main floor slab(under the bracing beam to be dismantled)is not completed,and the floor slab can not be routinely used to replace(dismantle)the bracing,the method of replacing(disassembling)the braces by the system composed of the columns of the main structure can be considered.(2)the system stiffness of the main structure column is limited,so it is necessary to make rational use of the number of the main structure column to ensure the system stiffness for stress transfer.(3)in general,the stiffness of the system reconstituted by the columns of the main structure is less than that of the whole floor,and the bracing stiffness can be reduced appropriately in the calculation model(taking the whole floor stiffness as 75%),the calculation model can be applied to practical engineering and has achieved good results.