Mechanism, Stability and Remediation of a Large Scale External Waste Dump in China

This paper presents a study of the failure mechanism and control measures for a landslide at Dagushan Waste Dump. In addition to a summary of the site geological conditions, the observed landslide shape is described based on site investigations. It is shown that the dominant causes of the slope stability problem are softened silty clay due to rainfalls and the mechanical vibrations of a concrete batching plant at the slope toe. Failure mechanism analyses were performed by base friction test, which showed that the failure mode of Dagushan Waste Dump is a collapse-traction-push type landslide. Dump stability analyses were performed using the limit equilibrium method, which showed that safety factors of the waste dump decrease with the increase of water content of silty clay, and with the increase of average vibration acceleration of mechanical vibrations. The water content of silty clay has a much greater influence on dump stability than the average vibration acceleration. Remedial measures to stabilize the unstable zones include slope reshaping, platform compacting, drainage system ameliorating, and cracks filling. The results indicate that these measures are effective in controlling the landslide.