Reactivation of a huge ancient landslide by surface water infiltration
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An ancient landslide, situated in Deqin County, Yunnan Province, China, was used to investigate the reactivation by water infiltration. This study considers the infiltration process and landslide stability using finite-element method (FEM)-based models. The results show that the reactivation of old landslide deposit was triggered by the long-term leakage of diversion ditch before October 2012, and the reactivation was triggered again by the intense rainfall on 7–9 October 2012. The old cracks, which formed in the earlier reactivation of landslide, played a key role for the rainfall infiltration. They offered a preferential path for much more rainfall to infiltrate fast into deep soil, and caused wetting front to move down faster in landslide. The old slip zone with lower permeability was another important factor to cause the infiltrated water to accumulate and form a high pore water pressure above slip zone. Then the high pore water pressure decreased the shear strength of slip zone and triggered the reactivation of the old landslide deposit again.
KeywordsLandslide Rainfall infiltration Soil stability Finite-element-method Leakage of diversion ditch
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We are grateful to the academic and technical staff of the State Key Laboratory of Geohazard Prevention and Geo-Environment Protection (SKLGP) at the Chengdu University of Technology, China. This research was supported by the National Natural Science Foundation of China (Grant Nos. 41472274, 41672300) and Independent Subject Foundation of SKLGP (SKLGP2017Z010).
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