苏州地铁车站咬合桩围护结构的关键施工控制技术

以苏州地铁南施街站咬合桩围护结构应用为例,分析了咬合桩施工过程中咬合桩桩位控制、超缓凝混凝土的缓凝时间、桩内"混凝土管涌"的控制、"拔桩"的控制、分段施工节点连接控制等关键技术,开展了不同施工阶段下的基坑测斜变形观测研究。监测结果表明,围护墙体两端变形小、中间变形大,最大侧移点深度随着开挖不断下移,且最大侧向位移监测值始终在警戒值范围内,施工一直处于安全可控状态。

Key Technologies of Construction and Control for Retaining Structure of BCP in Suzhou Subway Station

Here,taking the application of BCP in the foundation excavation project of Nanshi Street Station of Suzhou subway for example,the key techniques of BCP construction are demonstrated in detail,including the precise control of BCP position,the setting time of super delaying concrete,the piping effect of the concrete in pile hole,the pile pulling operation and the sand pile connecting in segmented construction,etc.,and the observation for the lateral displacement of BCP retaining wall is made in different process.The results indicate that the lateral displacement of the retaining wall would be dominant at the center,while small at the ends,in the meanwhile,the largest height of the lateral displacement would be declined with the depth of excavation increased,and the largest displacement would still be under the trigger level,i.e.,the construction would be under safety and control.