某多层建筑地下车库整体筏板裂缝鉴定及原因分析

Crack inspection and reason analysis in a multi-storey building’s reinforced concrete raft foundation

地下相互贯通的7栋多层建筑,采用整体筏板基础,Ⅲ类场地,基础下存在软弱土层,仅个别主楼下进行1m厚的砂石换填压实,其余部分均采用天然地基。在主体结构完工后,主楼之间筏板出现大面积规则性裂缝,车库外墙也存在竖向八字裂缝。通过对地质情况、施工质量、地下水位、承载力验算和沉降计算进行分析排查,确定主楼与车库存在差异沉降、抗浮设计及筏板底部钢筋不满足规范要求,从而导致筏板基础出现大面积裂缝。本文研究可对近似地质条件的基础选型及相关裂缝鉴定提供参考借鉴。

The 7 Multi-story building with underground connected to each other is adopted by the whole raft foundation,Ⅲfield,and soft soil layer under the building foundation.Only few Individual buildings filled and replaced by 1 m thick slag,and the rest parts keep the original foundation.After the main structure is completed,large areas of regular cracks appear in raft among main buildings,and also there are vertical eight-character cracks in the exterior wall of the garage.According to the analysis and investigation of geological conditions,construction quality,underground water level,bearing capacity checking and settlement calculation,it is determined that there are differences in settlement between the main building and the garage,and anti-floating design and raft bottom reinforcement do not meet the specification requirements,which results in the large area of cracks in the raft foundation.This paper can provide reference to the basic type selection of similar geological conditions and the related crack appraisal.