针对深大基坑距离周边既有建筑极近、临近施工地铁线,存在支护要求高、施工难度大等特点,根据工程地质勘察及相关试验成果,提出了深大基坑桩锚支护方案.基于岩土室内试验、原位测试测取了地层参数,采用理正深基坑7.0软件进行了计算,分析了各工况下基坑的整体稳定性、抗倾覆稳定性、抗隆起稳定性.施工过程中,在不同开挖深度及不同开挖完成时间条件下针对坡顶位移、支护结构变形、地下水位、锚索拉力及监测范围内建(构)筑物变形、附近地表路面的变形开裂情况开展了全面高频率监测,结果显示开挖过程中坡顶水平及竖向位移均小于预警值,结构内力未见异常.可为相似复杂条件下深大基坑设计提供重要的指导和借鉴.%In allusion to the characters of deep foundation pit,such as extremely close to the existing buildings and subway construction,and existing great risks and difficulties in the construction of the foundation pit,and so on,based on the geological exploration and laboratory experiment data,combined pile-anchor to design the supporting measures was used for a deep foundation pit.The parameters of strata were gained by using indoor rock and soil test and in-situ tests,and Lizheng Deep Foundation Pit 7.0 software was also applied to make relevant calculation,the overall stability,the anti-incline stability and the anti-heave stability of foundation pit in different conditions were analysed separately.In the process of construction,aimed at the different mining depth and different finishing time of mining,high-frequency monitoring was widely carried out on the collapse of slope,the deformation of structure,the water level,and anchor tension,the deformation of buildings,the fracture of roads′surface.The monitoring result shows that,both the horizontal and vertical movements of the excavation slope were less than the pre-warning value,and the structural internal force was normal.The results can provide important guidance and reference for the design of similar deep foundation pit under complicated conditions.
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