不同降雨类型对粗粒土高路堤边坡稳定性影响分析

Stability analysis of coarse grained soil high embankment slope under different rainfall conditions

为了深入研究不同降雨类型下粗粒土高路堤边坡的稳定性,提出了一种能同时考虑路堤边坡内部饱和度、孔隙水压力及软化效应的稳定性分析方法;拟定了小雨、中雨、大雨以及暴雨4种降雨类型,设定一级坡高8m、二级坡高12m的A类和一级坡高10m、二级坡高10m的B类两类典型边坡,通过分析A,B两类方案填筑的路堤边坡在不同降雨工况下安全系数和塑性区的变化规律,提出了路堤边坡最佳填筑方案,探讨了最佳方案填筑的路堤边坡稳定性。研究结果表明,相同降雨类型下,A类方案填筑的边坡稳定性比B类边坡更好,表明依托工程高路堤边坡最佳填筑方案为A类;降雨0~12h内边坡安全系数下降较快,随着降雨持时的增加,安全系数下降趋势减缓;在相同的降雨持时下,边坡安全系数随着降雨强度的增加而逐渐减小,当降雨强度超出一定范围后,其安全系数下降趋势相差不大;降雨初期,水位线上升较快,但存在一定的滞后性,随着降雨持时的增加,水位线上升速率减慢并呈规律性上升;小雨对边坡塑性区分布影响较大,但随着降雨强度的增加,降雨强度不再是影响边坡塑性区分布的主要原因。

In order to further study the stability under different rainfall types of coarse grained soil high embankment slope, a method considering the embankment slope internal saturation, pore water pressure and the softening effect of stability is proposed; light rain, moderate rain, heavy rain and rainstorm these four types of rainfall are developed. There are two types of typical slope, in the class A slope, the height of first level slope is set to 8m, and the second level slope is set to 12m, in the class B slope, the height of first and second level slope is both set to 10 re.The optimal filling scheme of embankment slope is put for-ward by analyzing the variation law of safety factor and plastic zone of embankment slope filled by A and B schemes under different rainfall conditions, and the stability of the em- bankment slope of the best scheme is discussed. The research results shows, under the same rainfall type, the slope stability of class A scheme is better than that of class B slope, which shows that the best filling scheme of high embankment slope is A elass~ the safety factor of the inner slope decreases rapidly in the 0~12 h rainfall, as the duration of rainfall increases, the declining safety factor slows down~ under the same rainfall time, the slope safety factor decreases with the increase of rainfall intensity, when the rainfall intensity ex- ceeds a certain range, the safety factor decline trend is not much difference~ at the begin- ning of the rainfall, the water line rises rapidly, but there is a certain lag, and then the in- crease in rainfall time led to the slow rise in the water level and a regular increase in the rate, the rainfall has a great influence on the distribution of the plasticity of the slope, but with that the increase of the rainfall intensity, the rainfall intensity is no longer the main reason affects the distribution of the plastic zone.