基坑周边存在地沟时的稳定性分析及支护措施

In recent years, collapse accidents caused by a trench around the foundation pit have occurred during excavation of the foundation pit. After the foundation pit is supported according to the common support method, its overall stability is guaranteed.But horizontal thin soil layer between the trench and foundation pit wall will become a new unstable factor. If effective support measures are not taken, it will lead to collapse in small-scale area. The paper analyzes the internal force, deformation, failure mechanism in a foundation pit where a trench exists, and proposes a stability model and failure modes of the thin soil layer between the trench and foundation pit wall. The paper also defines the concept of "the critical aspecpt ratios" in the thin soil layer on the basis of the analysis of stability of thin soil and puts forward engineering measures in addition.