考虑多层软土地基固结的路堤整体稳定性分析方法  

Analysis Method of Overall Stability of Embankment Considering Consolidation of Multi-layered Soft Soil Foundation

作　　者：张瑜 肖世国[2] ZHANG Yu;XIAO Shiguo(Department of Geological Engineering,Southwest Jiaotong University,Chengdu 610031,China;Key Laboratory of High-speed Railway Engineering,Ministry of Education,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]西南交通大学地质工程系,成都610031 [2]西南交通大学高速铁路线路工程教育部重点实验室,成都610031

出　　处：《铁道建筑》2021年第7期89-94,共6页Railway Engineering

基　　金：国家自然科学基金(51578466);中铁二院工程集团有限责任公司科研项目(KYY2018110(18-20))。

摘　　要：针对多层软土地基上填筑路堤的梯形荷载作用模式,基于Boussinesq理论确定地基中附加应力以及多层地基的边界条件、连续性条件及初始条件,求解多层地基竖向一维固结方程,进而根据有效应力原理与库伦强度定理,建立地基中任意点处抗剪强度与点固结度的关系,并将其引入边坡稳定性分析的极限平衡条分法中,给出了基于Fellenius法、简化Bishop法和Morgenstern-Price法的考虑地基固结的路堤-地基整体稳定系数及最危险滑面计算方法。结果表明:随着地基固结度的增大,稳定系数呈非线性增大,最危险滑面切入地基深度逐渐变小,本文基于简化Bishop法的稳定系数计算值比FLAC 3D软件计算结果平均小6%~7%;在较低的地基固结度时,本文算法计算结果大于现行铁路规范方法,当地基固结度达到90%后,二者较为接近;规范法计算结果偏保守的主要原因在于其计算地基固结致滑面强度增长时,忽略了滑面切入地基段相应的地基土自重。Aiming at the trapezoidal load mode of embankment on multi-layer soft soil foundation,based on the Boussinesq theory,the additional stress in the foundation and the boundary conditions,continuity conditions and initial conditions of multi-layer foundation under the trapezoidal embankment loading mode were determined.The vertical onedimensional consolidation equation of multi-layer foundation was derived.According to the effective stress principle and Coulomb’s strength theory,the relationship between the shear strength and the consolidation degree of any point in the foundation was established.By introducing the relationship into the limit equilibrium slice method of slope stability analysis,and the calculation method of the embankment foundation overall stability coefficient and critical sliding surface considering the foundation consolidation was given based on Fellenius method,simplified Bishop method and Morgenstern-Price method.The results show that:with the increase of the consolidation degree,the stability coefficient increases nonlinearly,and cut depth of the critical slip surface in the foundation is decreasing.The stability coefficient obtained by the simplified Bishop method is averagely 6% to 7% less than that by FLAC 3D.When the consolidation degree of foundation is low,the calculation results of this algorithm are larger than those of the current railway code method.When the consolidation degree of foundation reaches 90%,the results of two methods are close.The main reason for the conservative calculation results of the standard method is that the self-weight of the foundation soil corresponding to the sliding surface cut into the foundation section is ignored,when calculating the strength increase of the sliding surface caused by foundation consolidation.

关 键 词：路堤 多层软土地基 理论分析 数值模拟 固结度 稳定系数 最危险滑面 

分 类 号：U213.11[交通运输工程—道路与铁道工程]