降雨入渗对泥岩–土混填路堤稳定性的影响

 降雨入渗是诱发泥岩–土混填路堤边坡失稳的主要因素之一，为了揭示降雨对泥岩–土混填路堤边坡稳定影响的变化规律，选取济邵高速公路一典型路段的泥岩–土混填路堤边坡进行人工降雨模拟试验，对边坡土体中的孔隙水压力、边坡土压力和变形进行监测；探讨雨水入渗对路堤边坡稳定性的影响，推断滑坡的形成机制和预测边坡的稳定发展趋势。原位综合监测和数值分析结果表明：降雨入渗影响下泥岩–土混填路堤边坡的滑动变形区的变形量以坡面最大。裂缝的出现使得雨水更容易进入深层土体，土体吸水崩解、软化，强度急剧下降，使得边坡的稳定性安全系数在降雨后显著降低。

EFFECT OF RAINFALL INFILTRATION ON STABILITY OF MUDSTONE-SOIL MIXTURE EMBANKMENT

Rainfall infiltration into mudstone-soil mixture embankment is one of the most important factors affecting slope stability. In order to understand the landslide mechanism of mixture embankment induced by rainfall infiltration，the artificial rainfall simulation tests are carried out on a typical highway mudstone-soil mixture embankment of Jiyuan—Shaoyuan expressway. Some field variables of embankment slope during the rainfall are monitored，such as pore water pressure，stress state，deformation and surface displacement of soils. The influences of mudstone-soil mixture embankment slope stability due to rainfall infiltration are discussed. The initiation and formation mechanism of landslide are researched and the trends of development of the slope stability are also evaluated. The field monitoring results and numerical analysis both show that the deformed zone of mudstone-soil mixture landslides caused by rainfall infiltration lies under the slope，and the maximum deformation value appears on the slope surface. The crack makes the rainfall easily get into the deep soil layer，and thus a retaining water layer under slope surface will emerge. The layer causes the increase of the pore water pressure and the decrease of the effective stress together with the disintegrative and suction softening of mudstone. The decrease of strength has great effect on factor of safety(FOS) of the embankment slope stability.