仪征市棕黄色粉质黏土滑坡机制分析

Analysis of landslide mechanism for brown-yellow silty clay in Yizheng city

为研究仪征市某公路的自然滑坡机制,采用现场钻探、取样测试和数值模拟的方法,确定了滑动面、土体物理力学参数。结果表明:土体属粉质黏土,而根据粒组含量确定该土层应为粉土-粉砂,5次反复剪后土体摩擦角由初始的16.5°下降至7.4°;随着降雨持续,土体浸润线从坡脚向上不断上升,导致土体饱和区域不断扩大。边坡初始稳定性系数为1.30,考虑强度较低的连续性降雨(降雨量平均32 mm/d)条件下,4 d后稳定性快速下降,而持续时间较短的强降雨(降雨量133mm/d)对边坡土体内地下水位变化影响较小。该研究可为该地区类似土层中的边坡稳定性分析和开挖设计提供依据。

This paper aims to study natural landslide mechanism for a certain highway in Yizheng city.The study determines the sliding surface and the physical and mechanical parameters of soil by means of field drilling,sampling test and numerical simulation.The results show that the soil is silty clay,which is determined to be silt-silty sand according to particle composition content.After repeated shearing five times,the friction angle of the soil decreases from initial 16.5°to 7.4°;With continuous rainfall,the rain infiltration line goes up continuously from the toe,and soil saturation zone expends continuously.The initial stability coefficient of the slope is 1.30.Under the condition of continuous low intensity rainfall(average rainfall 32 mm/d),the stability decreases rapidly after 4 days.However,the short-term heavy rainfall(rainfall 133 mm/d)has little effect on the change of groundwater level in soils of the slope.The research conclusion can provide a basis for slope stability analysis and excavation design in similar soil layers in this area.