基于临界稳定断面的地下深基坑岩土稳定性勘察技术  

Geotechnical Stability Investigation Technology of Deep Foundation Pit Based on Critical Stability Section

作　　者：郑宵[1] ZHENG Xiao(Department of Design,Minbei Vocational and Technical College,Nanping Fujian 353000,China)

机构地区：[1]闽北职业技术学院设计系,福建南平353000

出　　处：《菏泽学院学报》2021年第5期65-70,共6页Journal of Heze University

基　　金：福建省教育厅中青年教师教育科研项目(JAT191528);2017年度福建省中青年教师教育科研项目(JAT171110);福建省中青年教师教育科研项目(JAS161115)。

摘　　要：提出基于临界稳定断面的地下深基坑岩土稳定性勘察技术,实现了地下深基坑岩土稳定性定量分析.通过创建地下深基坑岩土有限元模型,提出基于极限剪应变的岩土稳定性判据,利用关键点位移计算方法获得破坏判据.通过轴心抗压和抗剪应变数值计算、岩土自承载安全系数与所需支护力计算,完成地下深基坑岩土稳定性勘察.实验结果表明:深基坑挖掘中,岩土的稳定性与剪应变、轴应变和体应变呈正相关,与岩土侧应变呈负相关;岩土等级相同情况下,深度越小,临界稳定断面越大,岩土自承载安全系数越大.该技术勘察到的深基坑临界稳定断面尺寸与在无系统支护条件下挪威Q法得到的最大断面尺寸大致符合,验证该技术具备勘察合理性.In this paper,the geotechnical stability investigation technology of underground deep foundation pit based on critical stability section is proposed to realize the quantitative analysis of geotechnical stability of underground deep foundation pit.By establishing the geotechnical finite element model of underground deep foundation pit,a geotechnical stability criterion based on ultimate shear strain is proposed,and the failure criterion is obtained by using the key point displacement calculation method.The geotechnical stability investigation of underground deep foundation pit is completed through the numerical calculation of axial compression and shear strain,the calculation of geotechnical self-bearing safety factor and required support force.The experimental results show that the stability of rock and soil is positively correlated with shear strain,axial strain and volumetric strain,and negatively correlated with lateral strain of rock and soil,and the smaller the depth is,the larger the critical stable section is and the greater the safety factor of geotechnical self-bearing capacity is under the same geotechnical grade.The critical stable section size of deep foundation pit surveyed by this technology is roughly consistent with the maximum section size obtained by Norwegian Q method without systematic support,and the rationality of the survey is verified.

关 键 词：临界稳定断面 地下深基坑 岩土 稳定性 勘察技术 

分 类 号：TU452[建筑科学—岩土工程]