摘要
稳定性分析是路堤设计中的关键环节。针对新型预应力路堤,提出一种基于极限平衡状态计算其边坡安全系数的新方法。该方法主要包含滑动面附加应力计算法与等效条间力计算法。基于弹性理论近似推导预应力路堤内潜在滑动面上的附加应力解析公式,并通过应力状态分析得到滑动面上任一点处的法向和切向附加应力计算式。结合滑动面附加应力计算法、条分法及等效条间力计算法,并考虑铁路路基受荷特点,提出新型预应力路堤稳定性分析的极限平衡法。该方法适用于任意形状滑裂面,计算公式简便,且分析过程无需迭代试算。算例分析表明:预应力在路堤潜在滑动面上引起的附加应力并非全部起抗滑作用,局部小区域存在促滑效应。相较于传统极限平衡法对预压应力的处理方式,提出的方法考虑了预应力的连续扩散效应,所得安全系数偏于安全。最后,采用数值方法进一步论证了方法的可靠性。
Stability analysis is essential in the design of an embankment.A new limit equilibrium based method is proposed to calculate the factor of safety of a newly developed prestressed embankment.It consists of an analytical method for computing additional stresses on a sliding surface and a method for calculating inter-slice forces.First,analytical formulas are derived to approximately calculate the additional stress components on a potential sliding surface using the elastic theory,and the additional normal and shear stresses at any point of the sliding surface are obtained based on stress state analyses.Then,a limit equilibrium method combining the additional stress calculation method,slice method,inter-slice force calculation method,and the loading characteristics of railway subgrades is proposed to analyze the stability of a prestressed embankment.The proposed method is applicable to arbitrary shaped sliding surfaces,the calculation formulas are concise,and the analysis process does not need iteration trial calculations.Example analyses demonstrate that the additional stresses on the potential slip surface of an embankment resulted by the prestress are not all anti-slide,and there are sliding effects in small local areas.Compared with the traditional limit equilibrium method on treating the compressive prestress,the proposed method considers the continuous propagation effects of the prestress,and the analyzed safety factor is biased towards safety.Finally,numerical methods are used to further demonstrate the reliability of the proposed method.
作者
徐方
张期树
冷伍明
邓志龙
董俊利
刘思慧
XU Fang;ZHANG Qi-shu;LENG Wu-ming;DENG Zhi-long;DONG Jun-li;LIU Si-hui(School of Civil Engineering,Central South University,Changsha,Hunan 410075,China;National Engineering Laboratory for High Speed Railway Construction,Central South University,Changsha,Hunan 410075,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2022年第S01期431-442,共12页
Rock and Soil Mechanics
基金
国家自然科学基金(No.51978672,No.51709284,No.51678572).
关键词
预应力路堤
稳定性
极限平衡法
附加应力
条间力
prestressed embankment
stability
limit equilibrium method
additional stress
inter-slice force
