Abstract: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.