杭州软土地区某桩锚支护基坑的监测分析

Monitoring and Analysis of a Foundation Pit Supported by Piles and Anchors in Soft Soil Area of Hangzhou

摘要:

以杭州地区某地下式污水处理厂为背景，结合基坑变形监测数据，探讨了旋喷扩大头锚索+排桩支护方案在软土地区的应用可行性。结论包括：桩锚支护形式在软土地区大面积基坑中能有效控制基坑的变形，减小周边环境影响，地下式污水处理厂基坑采用扩大头锚索加排桩支护方案是经济可靠的。基坑的桩身侧向位移变形曲线呈“鼓肚型”，围护桩的顶部位移较小，最大水平位移位于开挖面附近。基坑实施期间，应注意锚索在高水位、砂质土层中的施工影响，并可通过局部降水等措施减小锚索施工影响。

Abstract:

Taking an underground wastewater treatment plant (WWTP) in Hangzhou as the research background, and combined with deformation monitoring data of foundation pit, the application feasibility of the rotary jet grouting expanded head anchor cable + row pile support scheme in soft soil areas is discussed. The research conclusions are that the pile-anchor support form can effectively control the deformation of large-area foundation pits in soft soil areas and reduce the impact on the surrounding environment. The scheme of using expanded head anchor cables plus row pile support for the foundation pit of underground WWTP is economical and reliable. The lateral displacement deformation curve of the foundation pit pile presents a “bulging shape”, where the top displacement of the retaining pile is relatively small, and the maximum horizontal displacement occurs near the excavation surface. During the implementation of the foundation pit, the attention should be paid to the construction impact of anchor cables in high-water-level and sandy soil layers, and the measures such as local dewatering can be taken to reduce the construction impact.