砂土地层基坑开挖与邻近建筑物相互影响关键参数分析

基坑开挖会对邻近建筑物产生影响，建筑物的存在也会增加基坑施工的风险，开展基坑与邻近建筑物的相互影响研究具有重要意义。以某深基坑工程为背景，通过现场监测数据分析基坑开挖对围护桩位移的影响，然后建立三维数值模型，并与现场监测进行对比验证了模型的准确性。最后分析了围护桩刚度、建筑物层数及基坑与建筑物相对位置等参数下基坑与建筑物的相互影响规律。研究结果表明：采用围护桩结合锚索支护会显著减小基坑开挖引起的围护桩变形，基坑开挖引起的建筑物基础沉降和水平位移随围护桩刚度的增加变化幅度均在5%以内；建筑物层数每增加5层，建筑物基础的沉降和水平位移分别增加约8%和10%，靠近建筑物的基坑围护桩水平位移增加约5.5%；在建筑物与基坑的夹角在30°以上时，基坑开挖引起的建筑物基础变形均在2 mm以内，引起的围护桩水平位移均在0.8 mm以内。研究结果可以为后续类似工程提供参考和借鉴。

Key Parametric Analysis of the Interaction between Excavation and Adjacent Buildings in sandy soil stratum

The excavation of the foundation pit will have an impact on the adjacent buildings and the presence of the buildings will increase the risk of the construction of the pit. It is important to carry out studies on the interaction between the excavation and the adjacent buildings. Taking a deep excavation project as the background, the influence of excavation on the displacement of the enclosure pile was analyzed through on-site monitoring data, and then a three-dimensional numerical model was established and compared with the on-site monitoring data to verify the accuracy of the model. Finally, the interaction behavior between the deep excavation and the building was analyzed under the parameters of the stiffness of the enclosure pile, the number of storeys of the building and the relative position of the deep excavation and the building. The results show that the use of retaining piles combined with anchor cable support will significantly reduce the deformation of retaining piles caused by excavation. The settlement and horizontal displacement of the building foundation caused by the excavation are within 5% with the increase in the stiffness of the bollard piles. The settlement and horizontal displacement of the building foundations increase by approximately 8% and 10% respectively for each additional 5 storeys of the building, and the horizontal displacement of the foundation piles near the building increases by approximately 5.5%. At an angle of 30° or more between the building and the excavation, the deformation of the building foundation caused by the pit excavation was within 2 mm, and the horizontal displacement of the encasement piles was within 0.8 mm. The results can be used as a reference for similar projects in the future.