条形荷载下不排水土坡破坏模式判定及极限承载力估算  

NUMERICAL ANALYSIS FOR FAILURE MODE AND ULTIMATE BEARING CAPACITY OF STRIPING FOOTINGS ON CREST OF UNDRAINED SLOPES

作　　者：刘文红[1] 李同录[1,2] 李萍[1] 

机构地区：[1]长安大学地质工程与测绘学院,西安710054 [2]中国地质调查局西安地质调查中心国土资源部黄土地质灾害重点试验室,西安710054

出　　处：《工程地质学报》2016年第2期197-203,共7页Journal of Engineering Geology

基　　金：国家自然科学基金(No.41372329;41272283);国家重点基础研究发展计划(973计划)项目(No.2014CB744701)资助

摘　　要：为了确定边坡放置地基的极限承载力,采用弹-理想塑性有限元,分析了不排水土坡(φ_u=0)的坡肩上放置条形基础的地基极限承载力。结果表明,不排水土坡地基极限承载力仍可沿用Terzaghi水平地基极限承载力计算公式q_u=c_uN_c。不考虑重度条件下,土坡地基的破坏模式类似于水平地基破坏模式,承载力系数Nc与极限分析法计算的结果一致;考虑重度条件下,可用土坡实际状态的Taylor数与其极限状态的Taylor数的差值ΔN作为判别指标,当该值较小时将发生边坡破坏模式,较大时发生地基破坏模式,找出了两种破坏模式的ΔN分界点,确定了N_c与ΔN的关系,建立起坡肩作用条形荷载下不排水土坡极限承载力计算公式。This paper estimates the ultimate bearing capacity of foundations on the slope crests.It uses the elasto-plastic finite element method（FEM）.It simulates the striping footings on the crest of undrained slopes （φu =0）.The results show that the ultimate bearing capacity can be expressed as qu =cu Nc .When the unit weight of soil is ignored,Nc estimated by FEMis highly agreeable with that calculated by limit analysis.The failure mode is similar to the foundation on the horizontal terrain.When the unit weight of soil is taken into account,the coefficient Nc can be reduced more.The parameter ΔN is defined as the difference of the slope＇s stability number defined by Taylor from the slope＇s real state to the limit state.It can be used as determinant.The striping footing＇s failure can develop into whole slope failure when the ΔN is smaller,as well as foundation failure when the ΔN is bigger.The critical value of ΔN for failure mode change is estimated.Then the Nc-ΔN relationship is constructed.The equation for the ultimate bearing capacity of striping footings on the crest of undrained slopes is built.

关 键 词：边坡 地基 极限承载力 破坏模式 有限元 

分 类 号：P642[天文地球—工程地质学]