含砾黏性土路堑边坡稳定性分析

Analysis on Stability of a Cut Slope of Gravel Cohesive Soils

现场调查和研究发现,仪征市青长线部分地段拟对地基进行开挖,形成最高达20 m的路堑边坡,边坡稳定性主要受厚度较大的含砾粉质黏土层控制。黏土中砾石含量变化大,土体强度受砾石含量影响。场区内有多处滑坡迹象,滑动面位于含砾粉质粘土层中,通过对滑动面上的强度参数进行反算,得到砾石含量变化时的土体强度参数值。按照不同情形下土体的强度对不同坡比条件下的边坡稳定性系数进行计算。建议在该土层中进行放坡时,坡比为3∶1或坡比为2∶1时分台阶开挖为宜。研究结果可为该地区类似边坡工程提供参考。

Field investigations and studies indicate that the stability of a cutting slope along Qing-Chang Line,Yizheng City,is mainly controlled by the thick silty clay layer including a large amount of gravel.The maximum height of the cutting slope would reach 20 m.The gravel content in the clay varies greatly,the strength of the soils is strongly affected by the gravels.Combined with the site topography and landslide investigation,it is found that the sliding surfaces were through the layer of silty clay,so the strength parameters along the sliding surface were inversely evaluated,the soil strength parameter values with the change of gravel content were obtained.According to the strength parameters of the soil under different conditions,the stability coefficients of slopes under different slope ratio were analyzed.It is recommended that the slope ratio should be 3H:1V or 2H:1V,if the slope is cut in the cohesive soil layer.