Experimental and numerical investigations of a catastrophic long-runout landslide in Zhenxiong, Yunnan, southwestern China

On 11 January 2013, a catastrophic landslide of similar to 0.2 million m(3) due to a prolonged low-intensity rainfall occurred in Zhenxiong, Yunnan, southwestern China. This landslide destroyed the village of Zhaojiagou and killed 46 people in the distal part of its path. The displaced landslide material traveled a horizontal distance of similar to 800 m with a vertical drop of similar to 280 m and stopped at 1520 m a.s.l. To examine the possible mechanism and behavior of the landslide from initiation to runout, the shear behavior of soil samples collected from the sliding surface and runout path was examined by means of ring shear tests. The test results show that the shear strength of sample from the sliding surface is less affected by shear rate while the shear rate has a negative effect on the shear strength of runout path material. It is suggested that the source and runout path materials follow the frictional and Voellmy rheology, respectively. Post-failure behavior of the landslide was modeled by using a DAN-W model, and the numerical results show that the selected rheological relationships and parameters based on the results of ring shear tests may provide good performance in modeling the Zhenxiong landslide.