风化岩土质的地铁基坑开挖仿真研究

Simulation study on the excavation of subway foundation pits in weathered rock and soil

为研究风化岩土质深基坑在开挖过程中的变形演化规律,以长沙市某地铁深基坑工程为依托,用PLAXIS 3D软件建立三维数值模型,分析基坑开挖深度、载荷位置、载荷大小对深基坑开挖过程变形的影响规律。研究结果表明:风化岩土质地铁基坑在开挖过程中,其形变主要发生在土层。当载荷20 kN/m^(2)且距离基坑为5 m时,围护桩的最大偏移0.72 mm;当载荷达到60 kN/m^(2)时,地表的最大沉降为70.90 mm。该结果可为类似风化岩土质基坑设计提供参考。

To study the deformation evolution of weathered rock and soil strata in deep excavation pits,Based on a subway deep excavation project in Changsha,a three-dimensional numerical model was established by using PLAXIS 3D.The influence of excavation depth,load position,and load magnitude on the deformation of deep excavation pits during the excavation process were analyzed.The research results indicate that in the excavation process of subway foundation pits in weathered rock and soil,deformation mainly occured in the soil layer.When the load of 20 kN/m^(2)and 5 m away from the pit,the maximum lateral displacement of the retaining pileis was 0.72 mm.When the load reaches reached 60 kN/m^(2),the maximum settlement of the ground surface was 70.9 mm.These results can serve as a reference for the design of foundation pits in similar weathered rock and soil conditions.