Characteristics and mechanism of the landslide in Yongguang village, Minxian County, China
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Characteristics and mechanism of the landslide in Yongguang village, Minxian County, China Qian Wang1,2,3,4 · Zhenming Wang2 · Yongqi Su4 · Xiumei Zhong1,4 · Lanmin Wang1,3,4 · Haiping Ma4 · Guoxing Zhang5 · Edward E. Woolery6 · Kun Liu1,4 Received: 25 March 2020 / Accepted: 28 September 2020 © Springer Nature B.V. 2020
Abstract More than 2330 landslides/mudflows in loess were triggered by the 2013 Minxian earthquake (MS 6.6) in its epicentral area in Minxian County, Gansu, China. A comprehensive investigation, including in-situ and laboratory tests, was conducted for the largest landslide/ mudflow in Yongguang village in order to gain a better understanding of the mechanism and rainfall impact on the landslides/mudflows. A series of triaxial laboratory tests showed that the strength of loess is significantly reduced with increased water content. The static and dynamic parameters of loess, obtained from in-situ and laboratory tests, were used to analyze ground-motion site response. The field observations and site-response analyses suggested that peak ground accelerations generated by the Minxian earthquake were in the range of 0.2–0.4 g in the epicentral area. The static and dynamic parameters of loess were also used to analyze dynamic slope stability and liquefaction potential. The results showed that loess slopes would not fail or liquefy under dry conditions and ground motions with PGA of 0.2–0.4 g, whereas loess slopes would fail or liquefy under saturated conditions. Although difficult to quantify, the water content of the loess was significantly increased, even to the point of being partially saturated, by abnormally high rainfall prior to the earthquake. Thus, the abnormal rainfall before the earthquake was a contributing factor for the massive loess landslides/mudflows in the epicentral area. Keywords Loess landslide/mudflow · Ground motion · Site effect · Dynamic slope stability · Liquefaction * Qian Wang [email protected] 1
Key Laboratory of Loess Earthquake Engineering, China Earthquake Administration and Gansu Province, Lanzhou 730000, People’s Republic of China
2
Kentucky Geological Survey, University of Kentucky, Lexington, KY 40506, USA
3
Key Laboratory of Mechanics On Disaster and Environment in Western China, Ministry of Education of China, Lanzhou University, Lanzhou 730000, People’s Republic of China
4
Lanzhou Institute of Seismology, CEA, Lanzhou 730000, People’s Republic of China
5
Geological Hazard Research Institute, Gansu Academy of Sciences, Lanzhou 730000, People’s Republic of China
6
Department of Earth and Environmental Sciences, University of Kentucky, Lexington, KY 40506, USA
13
Vol.:(0123456789)
Natural Hazards
39°
Yinchuan Taiyuan
Xining Lanzhou
36°
Zhengzhou
Xi’an
Legend
33°
30° 99°
Yellow River Loess Plateau Landslides Region Qinghai-Tibet Plateau Study Area Epicenter Yongguang Landside site
102°
105°
(a)
108°
111°
114°
(b) Fig. 1 a Location of the study area; b active faults and earthquakes in the study area, modified by Feng et al. (2016)
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