复杂环境条件下深基坑支护设计和施工

Design and construction of a deep foundation pit support in complex environment

以某深基坑支护设计与施工为例,介绍了复杂环境条件下基坑支护方案设计和施工注意事项。该深基坑场地地质条件复杂,对防空洞和软弱粉土层不良地段,采用了封堵处理、双排桩联合锚索、钢筋混凝土角撑、桩间网喷等支护措施。锚索采用跟管钻进工艺成孔施工,解决了不良地质条件下钻进过程中卡钻、塌孔、钻不到锚索设计深度等问题。该基坑回填完工后监测结果表明:基坑位移控制良好,基坑周边道路、管线、房屋建筑最终变形量均满足设计要求。

With the project of design and construction of a deep foundation pit support as an example,the design and construction points for the foundation pit support in complex environment are introduced. The geological conditions of the deep foundation pit are complex,and such supporting measures as blocking treatment double-row pile plus anchor cable,reinforced concrete corner brace and spraying net between piles etc. are adopted for the air-raid shelter and adverse zones of soft weak silt layer. The anchor cable is drilled by following pipe drilling technology,which solves the problems of sticking,collapse and not drilling the design depth of anchor cable in the process of drilling under bad geological conditions. The monitoring results after completion of foundation pit backfilling show that the displacement of the foundation pit is well controlled,and the final deformation of the surrounding roads,pipelines and buildings all meet the design requirements.