河道对软土管线深基坑影响的数值分析

NUMERICAL ANALYSIS OF INFLUENCE OF RIVER CHANNEL ON DEEP FOUNDATION PIT OF SOFT SOIL PIPELINE

深基坑工程是一项涉及多个学科的复杂系统工程。受施工导行,施工占地等多方面影响,一些市政管线深基坑往往沿河道顺向布置,基坑开挖降水对周边及支护本身影响更加复杂。基于对软土模拟有很好结果的土体硬化模型(HS),以近河道工程实例为依托,考虑正常的坑内降水情况下,对基坑开挖引起的桩体变形、地表沉降、桩身受力等方面进行数值模拟分析,对比有无河道影响的不同之处。结果表明有无河道影响的基坑地表沉降、桩体变形、桩身受力、渗流场等方面均有较大差别。受近河道影响地面及桩身变形均不同程度增大且倾向于河道一侧,而受变形影响桩身受力有一定幅度减小。近河道一侧地下渗流场水体主要通过河水补给,因此切断河水的补给对于保证基坑安全是十分有必要的。

Deep foundation pit engineering is a complex system engineering involving many disciplines.Influenced by construction guidance,construction land and other aspects,some municipal pipeline deep foundation pits are of⁃ten arranged along the river course,and the impact of foundation pit excavation and water reduction on the surround⁃ing area and the support itself is complex.Based on the soil hardening model(HS)with good results for soft soil simu⁃lation,the numerical simulation analysis of a near-river project is taken to carry out on the pile deformation,surface settlement,and pile stress caused by foundation pit excavation,in which the differences between the influence of riv⁃er and non-river are compared,considering the normal precipitation in the pit.The results show that there are great differences in the ground settlement,pile deformation,and pile stress of foundation pits with and without river influ⁃ence.The overall performance is that the deformation of the ground and the pile affected by the near river increases in varying degrees and tends to be on the side of the river,while the stress of the pile affected by the deformation de⁃creases to a certain extent.The primary source of water for the underground seepage field adjacent to the river chan⁃nel is derived from the river,therefore it is imperative to cease the supply of river water in order to guarantee the sta⁃bility of the foundation pit.