Research on the formation mechanism of loess landslide in seasonally frozen ground region:a case study of Garangput landslide group
In seasonally frozen ground region landslides are become a more common geological disaster,which has attracted widespread attention in the world.Whether the physical processes of snow ablation and soil freez-ing and thawing in seasonally frozen ground region,as opposed to the non-monsoon freezing zone,have an im-pact on landslides deserves further study.A giant loess landslide group(Galamput landslide group)occurred on May 9,2002 in the Ili region of China provides an ideal case study.By using field survey,remote sensing im-age identification,meteorological data analysis and loess characteristic test,we attempt to explore the formation process and failure mode,and further reveal the instability mechanism of Galamput landslide group.The results show that the Garamput loess landslide group is composed of three landslides with a total volume of approximate-ly 17.355 million m3.The formation and development of the landslide group was a multi-stage and multiple slid-ing failure process.The Galamput landslide was the coupling triggering result of early snowmelt and post rain-storm.The snowmelt infiltration and soil freeze-thaw cycle in spring played an important role in the evolution process of slope deformation.The rapid infiltration of extreme rainstorm was the ultimate triggering factor of the landslide.In addition,special slope structures and stratigraphic combinations provide a material structural basis for the occurrence of loess landslides.Combined with the slope deformation process we established a deforma-tion failure model for loess slopes considering the effects of precipitation infiltration and freeze-thaw cycles,and proposed that the combination of static liquefaction on the slip surface and sliding liquefaction at the foot of the slope is an important mechanism inducing the occurrence of loess landslides.In the future,the risk of large-scale landslides in the Ten-zan's seasonally frozen ground region is extremely high with climate warming.This study can provide a new perspective on the formation process and failure mechanism of loess landslides,and is of great significance for understanding the early warning and risk assessment of landslide disasters in seasonally frozen ground region.
loess landslide groupfailure mechanismsnowmeltrainstormseasonally frozen ground region
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