Characteristics and dynamic process analysis of the 2018 Mabian consequent landslide in Sichuan Province, China
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ORIGINAL PAPER
Characteristics and dynamic process analysis of the 2018 Mabian consequent landslide in Sichuan Province, China Dongpo Wang 1,2
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Zhongwen Wang 1 & Yizhi Li 1 & Tianzhen Fan 1 & Chaojun Ouyang 3
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Feng Ji 1
Received: 2 December 2019 / Accepted: 20 March 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract A consequent slope, comprising weak planes in the same dip direction along the slope face, is the most dangerous type of rock slope. Herein, a consequent landslide that occurred on May 5, 2018, in Mabian County, Southwest China, was investigated. This landslide occurred in a region with a complex geological background and strong geological activity and is considered a typical consequent landslide. Field investigations and aerial photographic interpretations revealed that the rock mass slipped along the contact surface of the strongly and moderately weathered rock mass, triggered by continuous rainfall. A depth-integrated continuum method was used to study the dynamic process of the landslide. The applicability of the depth-integrated method was verified by comparing the moving boundary of the landslide extracted from a video with the simulation results. The results show that the velocity of the landslide first increased and then decreased from the top to the bottom of the landslide and reached a maximum of 21 m/s in the middle of the landslide. Based on this method, we predicted the potential danger zones and velocity distribution of unstable masses next to the Mabian landslide. On comparing the calculated results of a depth-integrated continuum method with the Scheidegger method, in the case of the Mabian landslide, a reduction factor λ was added to the Scheidegger formula to achieve a modified formula that determines the velocity of such consequent landslides relatively accurately. This work could provide reference for the study of landslide velocity and disaster prevention. Keywords Mabian landslide . Consequent slope . Numerical modeling . Dynamic process
Introduction A consequent slope is one in which the dip direction of the slope is the same as that of the bedrock. When the strength of weak intercalated layers decreases due to immersion in surface water or when the front edge of the slope is excavated to form a free surface, the rocks and soil on the bedrock are liable to slide downwards along the weak planes under the action of
* Chaojun Ouyang [email protected] * Feng Ji [email protected] 1
State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, Sichuan, China
2
University of Trento, 38100 Trento, Italy
3
Key laboratory of Mountain Hazards and Surface Process & Institute of Mountain Hazards and Environment (IMHE), Chinese Academy of Sciences, Chengdu 610041, China
gravity, thus forming a consequent landslide (Tung et al. 2013; Alan and Edward 2018; Ma et al. 2019). Consequent landslides are very common and occur suddenly, causing severe disasters (Evans 2006; Huang 2007; Longoni et al.
