Analysis of some special engineering-geological problems of loess landslide

Loess landslide is the most catastrophic geohazard in the northwest area of China. Non-earthquake-triggered loess landslides have occurred frequently in recent years with the development of economy and the increase of human activities in this area. The following features are representative for most loess landslides: crack development, steep backscarp, and retrogressive occurrence at the same site. The groundwater table in the South Jingyang Plateau, Shaanxi Province, has been significantly raised since 1976 and more than 50 landslide events at 27 sites have occurred. From 2005 to June 2007, several field investigations were taken at South Jingyang Plateau and the characteristics of loess landslides were studied. Some special engineering-geological problems of loess landslide are analyzed including the initial, travel mechanisms of long runout loess landslides, crack developing mechanisms, steep backscarp forming mechanisms and its stability assessment, landslide evolvement mechanisms. Based on the field works, the above mentioned engineering-geological problems are discussed.