考虑长期强度衰减的软岩路堤边坡稳定性分析

Stability Analysis of Soft Rock Embankment Considering Long-term Strength Attenuation

以某炭质页岩高路堤为例,考虑填料强度衰减特性,分析了不同降雨工况下易风化软岩路堤边坡稳定性。结果显示:降雨影响深度小于5 m的软岩常规高路堤,采用有限深度饱水参数计算的边坡稳定性系数比全断面饱水工况的高11.5%~17.4%;边坡稳定性系数随软岩强度衰减系数基本呈等比例线性递减,常规坡高坡率条件下设计的软岩高路堤边坡,考虑填料强度衰减后,安全系数很可能不满足要求,当炭质页岩强度衰减系数低于0.7时,应慎重采用20m以上高路堤边坡方案,综合坡率不宜陡于1∶1.75。

Take a high carbonaceous shale embankment as an example,with the attenuation characteristics of filler strength taken into consideration,the stability of the soft rock embankment that is easily weathered under different working conditions,were analyzed.The result shows that,for conventional high soft rock embankment with the depth of rainfall influence less than 5 m,the coefficient of slope stability calculated by finite depth saturation parameter is larger than that calculated in case of full-face saturation by 11.5%~17.4%;the coefficient of stability presents basically the scaled linear decline with the coefficient of soft rock strength attenuation,therefore,for high soft rock embankment designed in the condition of high ratio of conventional slope,with strength attenuation of filler taken into consideration,the safety coefficient is probably not to meet the requirement;in case of the coefficient of carbonaceous shale strength attenuation less than 0.7,the scheme of the embankment higher than 20 m should be adopted with cautions,wherein the comprehensive slope rate should not be steeper than 1∶1.75.