基坑开挖引起邻近管线变形的理论解析

基坑开挖将造成邻近地下预埋管线向基坑方向变形,针对此问题,采用弹性地基梁推导了管线的变形和内力解析式。传统的弹性地基梁模型中,在基坑开挖面施加卸载释放荷载,然后通过Mindlin解获取管线上的附加应力,详细分析了该法的不足,提出采用基坑开挖引起的土体附加变形作为弹性地基梁模型中的外部作用。分析了基坑一侧土体纵向变形适用的经验公式,并以此建立了弹性地基梁微分方程,给出了管线变形和内力的解析解,针对解析解的计算困难,进一步给出了加权残值解。考虑到实际工程为三维问题,推导了管线的扭矩求解公式,完善了弹性地基梁解答。

Theoretical Analysis on Deformation of Pipeline Caused by Adjacent Foundation Pit Excavation

The excavation of foundation pit will cause the deformation of buried pipeline adjacent to the pit. In order to solve this problem, the elastic foundation beam is used to derive the deformation and internal force of the pipeline. In traditional elastic foundation beam model, the released stress is loaded on the excavation face, and the stress on the pipeline is obtained by Mindlin solution. The deficiency of this method is analyzed, and the deformation of soil caused by excavation is proposed as the exterior load in the model. By analysis of the empirical formula of soil deformation on one side of foundation pit, the differential equation of elastic foundation beam is established, and the analytic solution of the deformation and internal force of pipeline are derived. Owing to the difficulty in calculation of analytic solution, the weighted residual solution is introduced. Considering that the project is a three-dimensional problem, the torque formula is derived for a complete elastic foundation beam solution.