Landslides at Qingjiang River in the Downstream Area of Shuibuya Dam Site, China

To enhance the general knowledge of landslides in China, the DAAD (German Academic Exchange Service) is financing an investigative project. As part of this project, at the Qingjiang (清江) River, a 10 km ² area downstream of the Shuibuya (水布垭) dam site was geologically and geotechnically mapped to gather information concerning landslides and their correlation to lithology, slope angles and texture. The geological mapping contained the characterization of the lithological units. The characterization of the shape of landslides and the classification of rocks into units with similar geotechnical behavior is contained in the geotechnical map. Samples were taken and investigated using X-ray diffraction to identify the clay minerals and geotechnical tests to determine the effective shear angle and cohesion of rocks and soils. Geotechnical mapping showed a close connection between lithology, slope angle and texture concerning the occurrence of landslides. Most landslides occur on the northern bank of the Qingjiang River where the dip angle of the bedding is nearly parallel to the slope, resulting in potential and effective slide planes. On the southern bank only sporadic and small landslides occur because the bedding is antipodal to the slope angle. This pilot work is a base for further and more detailed investigations in this area.