风化砂岩地区超高层建筑基坑开挖的力学特征

Mechanical characteristics of foundation pit excavation of super high-rise building in weathered sandstone area

兰州市风化砂岩地区超高层建筑天然地基的深基坑开挖是甘肃省首项天然地基的基坑开挖工程,其开挖方式、土层情况、力学性质等不同程度地影响着基坑开挖的力学特征.本文采用三轴实验和有限元数值模拟,分析该地区基坑开挖引起周围力学性质的变化情况.通过三轴实验获取风化砂岩的剪切强度参数,利用有限元数值模拟软件建立基坑开挖的三维数值模型,得到基坑开挖过程中的应力和变形曲线,并将模拟结果与现行规范进行对比分析,得到基坑开挖的可行性方案,为以后的类似工程提供参考意见.

The excavation of deep foundation pit of natural foundation of super high-rise building in weathered sandstone area of Lanzhou is the first foundation pit excavation project of natural foundation in Gansu Province.The mechanical characteristics of foundation pit excavation are affected by excavation method,soil layer and mechanical properties.In this paper,triaxial test and finite element numerical simulation are used to analyze the change of surrounding mechanical properties caused by foundation pit excavation in this area.The shear strength parameters of weathered sandstone are obtained by triaxial test,and the three-dimensional numerical model of foundation pit excavation is established by using finite element numerical simulation software.The stress and deformation curves in the process of foundation pit excavation are obtained.The simulation results are compared with the current specifications,and the feasibility scheme of foundation pit excavation is obtained,which provides reference for similar projects in the future.