Geotechnical hazards assessment on wind-eroded desert embankment in Inner Mongolia Autonomous Region, North China

Abstract

Inner Mongolia Autonomous Region is one of the severest desertification areas from wind erosion in North China, and it poses as a potential hazard factor for the slope stability of embankments. As the most common and abundant filler in embankment construction in the desert, Aeolian sandy soil is vulnerable to wind erosion. The embankment is susceptible to suffer from damage and lower slope stability due to wind erosion before placement of surface pavement and erosion resistance materials. The purpose of this paper is to evaluate the influence of wind erosion on the slope stability of embankment through a quantitative analysis of shear strength of Aeolian sandy soil within embankments. Field investigation was conducted to measure the wind field around embankment and the shear strength of Aeolian sandy soil within embankment. The shear strength variation was measured and proposed for a characterization of wind erosion resistance. Then, a model for calculating the progressive wind erosion process was suggested for evaluating the slope stability of wind-eroded embankment through the strength reduction theoretical simulation. The results show that wind erosion resistance of Aeolian sandy soil within embankment tends to increase gradually from slope surface to the core and from the shoulder to the toe. When the embankment suffers from wind erosion along prevailing wind direction, its slope has a much weaker resistance on the windward side. The maximum lateral wind erosion depth is about 0.2 times height of embankment. And factors of safety decrease gradually as wind erosion increases, it has affected the local stability of slope, but the slope global stability is not affected under this given wind erosion condition in this study. If wind erosion increases and wind erosion area expands further, the global stability of slope will be on the hazardous level. The speculative study is discussed between slope stability and geometric size of wind-eroded embankment. When the height of embankment increases and its slope becomes steep, its factor of safety decreases, and its slope stability reduces. The results indicate that embankments in Inner Mongolia Autonomous Region should be designed to be lower and gentler in consideration of wind erosion and also recommend scientific and effective protective measures to prevent further development of wind erosion based on proposed maximum lateral wind erosion depth from this study.