悬臂支挡基坑开挖的离心模型试验研究

Centrifugal Model Test of Cantilever Retaining Foundation Pit Excavation

采用离心场基坑开挖设备进行了粉质黏土悬臂支挡基坑开挖的离心模型试验,并根据试验结果分析了粉质黏土基坑变形规律和悬臂支挡结构土压力特性。结果表明:开挖过程中悬臂挡墙会朝坑内偏转,并伴随一定的挠曲变形;基坑变形依赖于挡墙的变形模式和大小,随挡墙位移增长,具有明显的阶段性;墙后土体位移随深度增加而减小,同一深度上随距挡墙距离减小而增加;墙后土压力随挡墙位移增加而下降,且下降速率逐渐减小,直至土压力达到极小值;土压力沿深度方向近似呈抛物线分布,极值点大致在4/5墙高处。

The centrifugal model test of silty clay cantilever retaining foundation pit excavation was carried out by using the centrifugal field foundation pit excavation equipment,and the deformation behaviors of silty clay foundation pit and the earth pressure characteristics of cantilever retaining structure were analyzed according to the test results. The results show that the cantilever retaining wall will deflect towards the pit during excavation,accompanied by a certain amount of flexural deformation. The deformation of foundation pit depends on the deformation mode and size of retaining wall,and has obvious stages with the increase of retaining wall displacement. The displacement of soil behind the wall decreases with the increase of depth,and increases with the decrease of distance from the retaining wall at the same depth. The earth pressure behind the wall decreases with the increase of retaining wall displacement,and the decline rate decreases gradually until the earth pressure reaches the minimum. The earth pressure is approximately parabolic along the depth direction,and the extreme point is about four fifths of the height of the wall.