深基坑开挖引起的支护结构受力特性研究

Study on Mechanical Characteristics of Supporting Structure Caused by Deep Foundation Pit Excavation

基于修正摩尔库伦本构模型,采用MIDAS/GTS对基坑开挖及支护全过程进行数值模拟,对深基坑开挖引起的支护结构受力特性进行了研究,并与实际监测结果进行对比分析.研究结果表明,基坑开挖引起的内支撑内力主要是轴力,开挖完成时最大轴力约为-2 085 k N,位于第三道内支撑处;基坑开挖引起的地连墙内力主要是弯矩,开挖完成时最大弯矩约为498. 1 kN·m,监测值约为522. 8 kN·m,均位于第三道内支撑和开挖面之间,现场实测结果与数值模拟结论一致.该研究成果对深基坑开挖过程中动态演化过程认识和变形破坏防治具有一定参考意义.

Based on the modified Mohr Coulomb constitutive model,the whole process of foundation pit excavation and support is numerically simulated by MIDAS/GTS. The mechanical characteristics of support structure caused by deep foundation pit excavation are studied and compared with the actual monitoring results. The results show that the internal force of internal support caused by foundation pit excavation is mainly axial force,and the maximum axial force at the completion of excavation is about-2 085 kN,which is located at the third internal support;the internal force of diaphragm wall caused by foundation pit excavation is mainly bending moment. When the excavation is completed,the maximum bending moment is about 498. 1 kN·m,and the monitoring value is about 522. 8 kN·m. There are positions between the third inner support and the excavation surface. The field measured results are consistent with the numerical simulation conclusions. The research results have certain reference significance for the understanding of dynamic evolution process and the prevention of deformation and failure in the process of deep foundation pit excavation.