非线性条件下加筋土边坡上限法的研究

Upper Bound Method for Reinforced Soil Slopes underNonlinear Mohr-Coulomb Yield Condition

大量的工程实践证明,岩土材料的屈服条件呈现非线性,且越是高地应力地区这种趋势越明显,但目前基于非线性的加筋土边坡稳定性分析的研究还较少。采用非线性摩尔-库伦屈服条件,以极限分析上限法为基础,研究边坡稳定性问题。引入新的强度参数c t和φt,以对数螺旋线为破裂面对非加筋土和加筋土进行研究,推导了非加筋土坡稳定性系数N s、安全系数F、非加筋土极限坡高H 1和加筋土坡极限坡高H 2的计算公式。在算例中采用MatLab程序进行计算,得出了较好的结果。总结了非线性参数m对抗剪强度指标参数c t和φt的影响,即随着m值的增加,φt值逐渐减小,而c t的值则先增大后减小;同时也得出了当其他条件不变时坡角β越大,边坡的极限坡高H越小的结果。

A large number of engineering practices have proved that the yield conditions of geotechnical materials are nonlinear.Such nonlinearity is more evident in areas of high geostress.However,at present,nonlinear studies on the stability of reinforced soil slope are inadequate.In this paper we research the slope stability under nonlinear Mohr-Coulomb yield condition via upper bound limit analysis.By introducing new strength parameters c t andφt,we obtain the calculation formulae of stability coefficient N s of non-reinforced soil,safety coefficient F,ultimate height H 1 of non-reinforced soil,and ultimate height H 2 of reinforced soil slope with logarithmic helix as fracture surface.Good results are obtained in a computation example using MatLab.Moreover,the influences of nonlinear parameter m on shear strength index parameters c t andφt are summarized.With the increase of m,φt decreases gradually while c t increases at first and then decreases.In addition,the limit slope height H reduces when slope angleβincreases with other conditions unchanged.