Abstract: The landslides at expressway embankment slopes that are adjacent to the river frequently occur and these hazards might seriously affect the operational safety of expressways. This paper presents a case history of a landslide deformation mechanism and mitigation of an expressway embankment slope adjacent to the river in Guizhou. The evaluation results indicate that the landslide of this embankment is a medium sized plenary slide that is adversely affected by the erosion of the river water at the embankment slope. At the toe of the embankment slope, the fluctuation of the river water level has a negative impact on the slope. The permeability of the fill embankment is high, and excessive slope deformation occurs under the heavy precipitations. The numerical analysis results indicate that large deformations are observed in both horizontal and vertical directions. These deformations are concentrated along the Chishuihe River side and close to the machinery access road. Based on the specific conditions of this embankment, a comprehensive mitigation plan was implemented: Anti slide caisson plus repairing the drainage ditch plus clearance upper instable rock plus sealing off roadway cracks plus the rehabilitation of the machinery access road. This measure is approved to have a satisfactory result.

Key words: Embankment Slope Adjacent to River, Embankment Slope, Deformation Mechanism, Mitigation Measures