含软弱夹层顺层边坡临界破坏范围分析

Analysis of critical failure range of bedding slope with weak interlayer

顺层边坡是工程中较为常见且难以治理的边坡,其临界破坏范围的确定一直是工程设计中的难点问题。本文针对某高速公路含软弱夹层顺层岩质边坡,采用二维及三维有限元方法对其临界破坏范围进行了研究,给出了2种临界破坏范围的确定方法,即开挖变形区分析法和底滑面塑性区分析法。结果表明:软弱夹层的存在对于顺层边坡的临界破坏范围有较大影响,传统基于开挖坡高比的经验分析法的应用受到了限制,建议采用有限元方法确定;顺层边坡的临界破坏范围存在一定的三维效应,不同里程处边坡破坏范围存在差异,突出山脊处破坏范围相对较大,三维同二维分析结果基本一致,实际工程中可采用二维计算结果作为设计依据。最后,设计了双排抗滑桩的支挡措施,成果可供类似含有软弱夹层的顺层边坡的设计参考。

The bedding slope is a relatively common and difficult-to-treat slope in engineering.The determination of its critical failure range has always been a difficult problem in engineering design.In this paper,the critical failure range of a bedding slope with weak interlayer on a highway is studied using two-dimensional and three-dimensional finite element methods,and two methods for determining the critical failure range are given——analysis method of excavation deformation zone and analysis method of plastic zone of bottom sliding surface.The results show that the existence of weak interlayer has a great influence on the critical failure range of bedding slopes.The application of traditional empirical analysis method based on the aspect ratio of excavation is restricted,and it is recommended to use finite element method to determine.The critical failure range of bedding slopes has a certain three-dimensional effect,and the failure range of the slope at different mileages is different.The failure range of the protruding ridge is relatively large.The results of three-dimensional analysis and two-dimensional analysis are basically consistent,two-dimensional calculation can be used as design basis in practical engineering.Finally,the supporting measures of the double-row piles are designed,and the results can provide a reference for the design of similar bedding slopes with weak interlayer.