Long-runout characteristics of the Yongguang 1# loess flowslide in Minxian County, Gansu Province

Flowslide in loessic regions, characterized by their elongated shape and tendency to slide and accumulate along channels or gentle hillslopes, frequently lead to devastating and unpredictable disasters. The Yongguang 1# flowslide in Minxian County, Gansu Province, caused by the Minxian-Zhangxian Ms6...

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Main Authors: Weijiang WU, Guoya WANG, Guoxin ZHANG, Letao FENG, Zhengxue YAO, Xing SU
Format: Article
Language:zho
Published: Editorial Office of The Chinese Journal of Geological Hazard and Control 2023-12-01
Series:Zhongguo dizhi zaihai yu fangzhi xuebao
Subjects:
Online Access:https://www.zgdzzhyfzxb.com/en/article/doi/10.16031/j.cnki.issn.1003-8035.202209046
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author Weijiang WU
Guoya WANG
Guoxin ZHANG
Letao FENG
Zhengxue YAO
Xing SU
author_facet Weijiang WU
Guoya WANG
Guoxin ZHANG
Letao FENG
Zhengxue YAO
Xing SU
author_sort Weijiang WU
collection DOAJ
description Flowslide in loessic regions, characterized by their elongated shape and tendency to slide and accumulate along channels or gentle hillslopes, frequently lead to devastating and unpredictable disasters. The Yongguang 1# flowslide in Minxian County, Gansu Province, caused by the Minxian-Zhangxian Ms6.6 earthquake at 7:45AM on July 22, 2013, claimed twelve lives and had a volume of approximately 23×104 m3. The landslide had a vertical difference of 175m between its front and rear edges, a total length of 1 030 m, and a ratio of 0.17, classifying it as a long-runout landslide. This paper explored the characteristics of the sliding process and the sliding velocities of different portions of the flowslide through field survey and a comprehensive analysis of the observation data of the sliding process, while also analyzing the sliding mechanism. Triggered by earthquake, the runout process of the flowslide has been affected by local terrain. The flowslide experienced two complex sliding stages of acceleration and deceleration. Initially, the landslide slid as a whole in the front platform area for 50 to 130 m, and then the front sliding body with an volume of about 6×104 m3 continued to slide along the front channel for 740 m, resulting in a maximum runout distance of 870 m. The entire sliding process lasted about 7 hours, with a maximum sliding speed of approximately 10.6 m/s, and an average sliding speed of 0.034 m/s. The formation of the Yongguang 1# landslide was influenced by the coupled effects of seismic activity and early-precipitation. The earthquake, preceded by heavy rainfall, led to infiltration and softening of the soil. During the sliding process, the high water content in the sliding zone generated high pore water pressure, and in some cases, liquefaction occurred. The channel-shaped topography and low permeability of the sliding zone soil caused a very slow dissipation of pore water pressure, resulting in a significant reduction in frictional resistance in the sliding zone soil throughout the entire sliding process, with a noticeable velocity-sustaining effect. These factors are the primary reasons for the long-runout of the Yongguang 1# landslide.
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spelling doaj.art-1234224b42c6487c9fe0657985a0fea02024-02-19T07:14:15ZzhoEditorial Office of The Chinese Journal of Geological Hazard and ControlZhongguo dizhi zaihai yu fangzhi xuebao1003-80352023-12-0134631210.16031/j.cnki.issn.1003-8035.202209046202209046Long-runout characteristics of the Yongguang 1# loess flowslide in Minxian County, Gansu ProvinceWeijiang WU0Guoya WANG1Guoxin ZHANG2Letao FENG3Zhengxue YAO4Xing SU5Geological Hazards Prevention Institute, Gansu Academy of Sciences, Lanzhou, Gansu  730000,  ChinaGeological Hazards Prevention Institute, Gansu Academy of Sciences, Lanzhou, Gansu  730000,  ChinaGeological Hazards Prevention Institute, Gansu Academy of Sciences, Lanzhou, Gansu  730000,  ChinaGeological Hazards Prevention Institute, Gansu Academy of Sciences, Lanzhou, Gansu  730000,  ChinaGeological Hazards Prevention Institute, Gansu Academy of Sciences, Lanzhou, Gansu  730000,  ChinaGeological Hazards Prevention Institute, Gansu Academy of Sciences, Lanzhou, Gansu  730000,  ChinaFlowslide in loessic regions, characterized by their elongated shape and tendency to slide and accumulate along channels or gentle hillslopes, frequently lead to devastating and unpredictable disasters. The Yongguang 1# flowslide in Minxian County, Gansu Province, caused by the Minxian-Zhangxian Ms6.6 earthquake at 7:45AM on July 22, 2013, claimed twelve lives and had a volume of approximately 23×104 m3. The landslide had a vertical difference of 175m between its front and rear edges, a total length of 1 030 m, and a ratio of 0.17, classifying it as a long-runout landslide. This paper explored the characteristics of the sliding process and the sliding velocities of different portions of the flowslide through field survey and a comprehensive analysis of the observation data of the sliding process, while also analyzing the sliding mechanism. Triggered by earthquake, the runout process of the flowslide has been affected by local terrain. The flowslide experienced two complex sliding stages of acceleration and deceleration. Initially, the landslide slid as a whole in the front platform area for 50 to 130 m, and then the front sliding body with an volume of about 6×104 m3 continued to slide along the front channel for 740 m, resulting in a maximum runout distance of 870 m. The entire sliding process lasted about 7 hours, with a maximum sliding speed of approximately 10.6 m/s, and an average sliding speed of 0.034 m/s. The formation of the Yongguang 1# landslide was influenced by the coupled effects of seismic activity and early-precipitation. The earthquake, preceded by heavy rainfall, led to infiltration and softening of the soil. During the sliding process, the high water content in the sliding zone generated high pore water pressure, and in some cases, liquefaction occurred. The channel-shaped topography and low permeability of the sliding zone soil caused a very slow dissipation of pore water pressure, resulting in a significant reduction in frictional resistance in the sliding zone soil throughout the entire sliding process, with a noticeable velocity-sustaining effect. These factors are the primary reasons for the long-runout of the Yongguang 1# landslide.https://www.zgdzzhyfzxb.com/en/article/doi/10.16031/j.cnki.issn.1003-8035.202209046flowslides in loesslong-runout flowslidepore water pressureliquefaction
spellingShingle Weijiang WU
Guoya WANG
Guoxin ZHANG
Letao FENG
Zhengxue YAO
Xing SU
Long-runout characteristics of the Yongguang 1# loess flowslide in Minxian County, Gansu Province
Zhongguo dizhi zaihai yu fangzhi xuebao
flowslides in loess
long-runout flowslide
pore water pressure
liquefaction
title Long-runout characteristics of the Yongguang 1# loess flowslide in Minxian County, Gansu Province
title_full Long-runout characteristics of the Yongguang 1# loess flowslide in Minxian County, Gansu Province
title_fullStr Long-runout characteristics of the Yongguang 1# loess flowslide in Minxian County, Gansu Province
title_full_unstemmed Long-runout characteristics of the Yongguang 1# loess flowslide in Minxian County, Gansu Province
title_short Long-runout characteristics of the Yongguang 1# loess flowslide in Minxian County, Gansu Province
title_sort long runout characteristics of the yongguang 1 loess flowslide in minxian county gansu province
topic flowslides in loess
long-runout flowslide
pore water pressure
liquefaction
url https://www.zgdzzhyfzxb.com/en/article/doi/10.16031/j.cnki.issn.1003-8035.202209046
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