降雨作用下路堤边坡水毁机理及影响因素分析

Analysis on water damage mechanism and influencing factors of embankment slope under rainfall

为明确降雨对路堤边坡内部渗流场以及稳定性的影响,对路堤边坡水毁机理及其主要影响因素进行了研究。在特定土质、压实度以及冲刷入渗时间等控制条件下,通过边坡模型试验探究降雨对边坡坡面冲刷破坏过程的特征,运用GeoStudio程序进行数值模拟分析,找出降雨作用下路堤边坡内部渗流场和稳定性的变化规律。结果表明:降雨过程中雨水冲刷造成边坡坡面结构破坏,而边坡内部受到雨水渗流作用导致稳定性降低,降雨作用从外到内对边坡造成影响;随着2种土质边坡压实度从85%提升至95%,砂性土边坡的冲刷量减少了46.18%,边坡安全系数提升了13.74%,黏性土边坡冲刷量降低了33.70%,安全系数提升了10.21%;随着降雨时间的增加,黏性土边坡后期冲刷深度趋于稳定,但砂性土边坡冲刷深度有增大的趋势;相同控制条件下,降雨前后黏性土边坡安全系数变化量小于砂性土边坡。因此,同等控制条件下,黏性土边坡的抗水毁性能以及整体稳定性均强于砂性土边坡,研究结果有助于更全面地了解降雨过程中路堤边坡的水毁机理及主要因素的影响规律,提高道路支撑的稳定性。

In order to clarify the influence of rainfall on the seepage field and stability of embankment slope,the mechanism of embankment slope water failure and its main influencing factors were studied.Under the specific control conditions of soil quality,compaction degree and erosion infiltration time,this study explored the erosion damage of subgrade slope under rainfall through slope model test,and then combined with GeoStudio program to find out the seepage field and stability change law of subgrade slope during rainfall.The results show that in the process of rainfall,the slope surface is scoured by rain water and the external structure is damaged,while the internal stability of the slope is reduced by the seepage action of rain water.The two effects from the outside to the inside simultaneously lead to the overall damage of the slope.With the increase of compaction degree of two kinds of soil slopes from 85% to 95%,the erosion amount of sandy soil slopes decreased by 46.18%,and the slope safety factor increased by 13.74%,while the erosion amount of cohesive soil slopes decreased by 33.70%,and the safety factor increased by 10.21%.With the increase of rainfall time,the scouring depth of cohesive soil slope tends to be stable in the later stage,while the scouring depth of sandy soil slope tends to increase;Under the same control conditions,the change of safety factor of cohesive soil slope before and after rainfall is smaller than that of sandy soil slope.Under the same control conditions,the water damage resistance and overall stability of the clay soil slope are stronger than that of the sandy soil slope.The research results are helpful for more comprehensive understanding of the water-damage mechanism of the embankment slope and the influence laws of the main factors in the process of rainfall,and improve the stability of the road support.