Abstract: Considering the deep foundation pit depth, geological condition, surrounding environment and construction period of Baiyin Yellow River Bridge, the supporting scheme of larsen steel plate foundation pit is scientifically selected. The construction scheme of drainage excavation, bottom sealing and then removing the bottom enclosing purlin structure reduces the bottom sealing thickness and ensures the one-time overall pouring of the cap. The calculation of the support structure with lizheng professional pit software shows that the stress, displacement and anti-uplift of the main support structure all meet the requirements. In addition, the calculation results of enclosing purlin structure by Midas software also meet the requirements. The construction practice shows that the measured deformation value of steel sheet pile is close to the theoretical calculation value, which fully shows that the calculated results are in good agreement with the actual engineering, and the simulation calculation can be used to guide the construction, providing a successful case for the bridge deep foundation pit supporting engineering with similar geological conditions and limited time limit.

Key words: deep foundation pit, support scheme, support structure calculation, enclosing purlin calculation

摘要： 结合白银黄河特大桥基坑深度、地质状况、周边环境和工期等因素,科学选择了拉森钢板的基坑支护方案。由于采取了排水开挖,封底后再拆除最下层围檩结构的施工方案,从而减小了封底厚度,保证了承台的一次性整体浇筑。采用理正深基坑专业软件对支护结构的计算表明:支护主体结构的应力、位移、抗隆起均满足要求。此外,采用MIDAS软件对围檩结构的计算结果也满足要求。施工实践表明,钢板桩的变形实测值与理论计算值接近,这充分说明计算结果与工程实际一致性好,模拟计算完全可以用来指导施工,为相似地质条件、工期受限的桥梁深基坑支护工程提供了一个成功的案例。

关键词: 深基坑, 支护方案, 支护结构计算, 围檩计算