复合土钉支护基坑开挖中侧向变形性状分析

针对上海市东方艺术中心超大面积的复合土钉支护基坑在开挖中引起的变形,采用二维有限元的方法,分析浅层基坑开挖过程中复合土钉支护结构的受力特点及基坑侧向变形情况。通过对有限元计算结果进行分析,并与实测数据对比,认为复合土钉支护可以将侧向位移控制在较小范围内;最后一层土钉拉力很小,可以节省掉;影响基坑侧向变形的土钉设计参数为土钉刚度和水平间距,但存在一个临界土钉刚度,当土钉刚度大于临界刚度时,其对基坑侧向变形的影响较小。

Analysis of Lateral Deformation during Excavation of Foundation Pit with Composite Soil-nail Support

To cope with the deformation of the composite soil-nail supported super large foundation pit during excavation for Shanghai Oriental Art Center, the 2-D finite element method is adopted to analyze the force on the composite soil-nail support structure and the lateral deformation during shallow excavation of the pit. Based on the result from the finite element calculation and comparison with the data measured, conclusions are drawn, i.e. the composite soil-nail support may confine the lateral movement to a small range, the soil-nails in the last layer are under very little tensile so can be taken away, and the parameters for design of the nail affecting lateral deformation of the pit are its rigidity and horizontal interval. But a critical rigidity exists. The nail has minimum impact on the lateral deformation of the pit when its rigidity is greater than the critical rigidity.