基坑围护结构最大侧移深度对周边环境的影响

围护结构最大侧移所在深度是衡量基坑变形的重要指标之一，而目前鲜有关于其对周边环境变形影响的研究。基于工程实测数据分析和有限元数值模拟，系统地研究了基坑围护结构最大侧移深度对邻近桩基础建筑物不均匀沉降和坑外深层土体位移场的影响。经研究发现：围护结构最大侧移的下移会导致坑外土体位移场扩大，进而降低相应区域的桩基础承载力，导致邻近桩基础建筑物发生显著的不均匀沉降。不同深度的土体经历复杂的竖向位移，且位移形态与围护结构最大侧移深度密切相关。随围护结构最大侧移深度的逐渐下移，坑外土体位移场向深层土体发展，且主要影响范围相应地扩大。在实际工程中，根据基坑周边环境合理地控制围护结构最大侧移所在深度，可有效降低基坑开挖对周边环境的不利影响。

Influences of depth of maximum lateral deflection of excavation support on adjacent environment

The depth where the maximum lateral wall deflection occurs during excavation is one of the key indicators for evaluating excavation deformations. To date, there are few studies involving the relationships between the depth of the maximum lateral wall deflection and the adverse influences on adjacent environment. Based on analysis of field monitoring data and finite element numerical simulations, the influences of depth of the maximum lateral wall deflection on both ground displacement and uneven settlement of buildings adjacent to excavation are investigated. It is found that the deeper the location of the maximum lateral wall deflection, the wider the ground displacement field and the greater the uneven settlements of buildings. The soil strata undergo various vertical displacements at different depths, and the displacement patterns are governed by depth of the maximum lateral wall deflection. As the maximum lateral wall deflection goes downwards, the ground displacement field of soil adjacent to pit extends to deeper level and the corresponding influence zone expands as well. The investigation results indicate that the excavation-induced adverse effects on adjacent environment could be mitigated effectively by controlling the location where the maximum lateral wall deflection occurs.