某软土深基坑设计及监测对比分析

Design and Monitoring Analysis of a Soft Soil Deep Foundation Pit

软土地区基坑开挖风险大,同时在地铁安保区内还必须严格控制基坑开挖对邻近地铁隧道的影响,因此在软土条件下位于地铁安保区内的基坑支护设计对变形控制要求极高。通过介绍深圳填海地区、地铁安保区内某软土深基坑支护设计方案,基于理正单元计算、三维有限元计算对设计方案进行分析验证,并将计算结果与第三方实际监测结果进行对比分析,分析表明咬合桩+钢筋砼支撑支护结构形式应用于地质条件较差的软土深基坑工程中具有较高的可靠度;将第三方实施监测数据运用到三维有限元模拟分析中进行反演分析能辅助设计预测支护结构及邻近地铁隧道的变形,从而更有针对性地调整支护措施。

It has a high risk to excavate foundation pits in soft soil areas,and the impact of foundation pit excavation on adjacent subway tunnels must be strictly controlled in the subway security area.Therefore,the deformation control on designing of foundation pit support in subway security areas under soft soil conditions is highly demanded.The support design scheme of a deep foundation pit in Shenzhen’s reclamation area and subway security zone is introduced in detail.The design scheme is analyzed and verified by rational element calculation and three-dimensional finite element calculation,and the calculation results are also compared with the monitoring data.The analysis shows that the form of occlusal piles+reinforced concrete support structure has high reliability in the application of deep foundation pits in soft soil.The monitoring data is applied to three-dimensional finite element to conduct inversion analysis,which can assist in the design and predict the deformation of the supporting structure and the adjacent subway tunnel,so as to adjust the supporting measures in engineering projects.