三门核电二期工程泵房基坑监测与稳定性分析

Foundation Pit Monitoring and Stability Analysis on Pump Room of Sanmen Nuclear Power Phase Ⅱ Project

三门核电二期工程3号、4号机组冷却水取水泵房软土深大基坑,水文地质条件复杂、周边设施保护要求高。对设计优化的基坑(长126 m×宽112 m×深32 m)进行系统监测,并开展开挖过程中的边坡、支挡结构的位移及支护桩内力、锚杆轴力变化分析,其目的为复核设计、参数修正和信息化施工等提供依据。监测数据表明:挡墙抗滑和桩锚结构的协同支护,有效限制了边坡沉降和水平位移,基坑整体稳定;预警与报警的发布,及时为开挖方案调整和应急对策提供依据。监测及成果分析,为本优化技术应用在3号、4号常规岛等深基坑支护提供了技术支持,也可供类似深基坑设计、施工、监测技术作参考。

As for Sanmen Nuclear Power Phase II Project No.3 rd,unit 4 th,the soft soil deep foundation pit for the cooling water intake pump station,hydrogeological conditions are complex,and the demand for surrounding facilities to be protected is high.For the design optimization of the foundation pit(length 126 m×width 112 m×deep32 m),the excavation process of the slope,the displacement of the supporting structure,the internal force of the retaining pile and bolt axial force were analyzed for the purpose of the review of design,parameter modification and information construction and other basis.The monitoring data showed that the coordinated support of the retaining wall anti-slide and the pile-anchor structure effectively limited the slope subsidence and horizontal displacement,the stability of the foundation pit.The release of the warning and alarm provided the basis for the excavation scheme adjustment and the emergency countermeasures in time.The analysis of monitoring results provided technical support for the application of this optimization technique in deep foundation pit support of No.3 rd and No.4 th conventional island,and it can also be used as reference for similar deep foundation pit design,construction and monitoring technology.