某地下空间开挖诱发周边建筑物变形异常实例

Example of Underground Space Excavation Induced Adjacent Building's Deformation

本文结合近年来北京地区地下空间开发利用中,诱发环境影响一典型工程实例,分析了场区岩土工程条件、地下支护结构设计方案、地下支护结构施工工艺、环境变形观测资料以及出现的异常现象等。找出了地下空间开挖诱发相邻建筑物裂缝的两个主要原因为:①北京顺义地区地层土灵敏度较高,施工扰动可使其抗剪强度指标降低,锚杆施工时支护结构地下连续墙发生的水平位移较大;②锚杆施工工艺不当,钻孔中出现了大量泥水喷涌现象,导致相邻建筑物地基基础倾斜过大。提出了锚杆施工时应采取降低地基土扰动的套管跟进、间隔跳打和二次压浆等相应技术措施。工程及时应用后建筑物沉降变形得到了有效控制。

Based on typical cases of the project induced environmen.tal impact in recent years in underground space development and utilization of Beijing, an analysis is carried out on field geotechnical conditions, the under- ground supporting structure design, underground supporting structure construction technology, environmental deformation data, as well as abnormal phenomena, and so on. Two main reasons of underground space excavation - induced cracks in adjacent buildings have been found： （1） Beijing ShunYi area has high soil sensitivity, the construction disturbance can reduce the shear strength index during the bolt construction, on the slurry - wall a greater level of dis- placement took place ; （2） the bolt construction technique is improper, there have been a large number of mud and water spewing in bore hole, leading to adjacent buildings foundation incline too much. This paper puts forward that in bolt construction measures should be taken to reduce soil disturbance, such as the casing following up, interval hop and beat, the second pressure grouting and other technical measures. After applications of the measures timely the building settlements have been effectively controlled.