This case study is about a landslide that occurred after 4 days of heavy rainfall,in the morning of June 29,2012,in Cengong County,Guizhou Province of China,geographical coordinated 108°20′-109°03′E,27...This case study is about a landslide that occurred after 4 days of heavy rainfall,in the morning of June 29,2012,in Cengong County,Guizhou Province of China,geographical coordinated 108°20′-109°03′E,27°09′-27°32′N,with an estimated volume of 3.3×106 m3.To fully investigate the landslide process and formation mechanism,detailed geotechnical and geophysical investigations were performed including borehole drilling,sampling,and laboratory tests coupled with monitoring of displacement.Also,a combined seepage-slope stability modeling was performed to study the behavior of the landslide.After the heavy rainfall event,the sliding process started in this area.The landslide development can be divided into different parts.The man-made fill area,spatially distributed in the south side of the landslide area with low elevations,slid first along the interface between the slope debris and the strongly weathered bedrock roughly in the EW direction.Consequently,due to severe lateral shear disturbance,the slope in the main sliding zone slid next towards the SW direction,along the sliding surface developed within the strongly weathered calcareous shale formation located at a depth of 25-35 m.This means it was a rainfall triggered deep-seated landslide.Finally,retrogressive failure of a number of upstream blocks occurred,which moved in more than one direction.The initial failure of the man-made fill area was the‘engine’of the whole instability framework.This artificial material with low permeability,piled up in the accumulation area of surface and sub-surface and destroyed the drainage capacity of the groundwater.The numerical modeling results agreed with the analysis results obtained from the laboratory and field investigations.A conceptual model is given to illustrate the formation mechanism and development process of the landslide.展开更多
Objective The 2014 Ludian Mw6.1 earthquake in Yunnan occurred in a mountainous area with complex tectonics and topography, which caused serious damage as well as co-seismic landslides of an unusual large scale. Becau...Objective The 2014 Ludian Mw6.1 earthquake in Yunnan occurred in a mountainous area with complex tectonics and topography, which caused serious damage as well as co-seismic landslides of an unusual large scale. Because the suspected seismogenic faults on the surface, distribution of aftershocks and focal mechanism solutions are not consistent, it remains difficult to determine what is the real causal fault or seismogenic structure for this event. Actually, it may imply the complicity of the seismic source at depth. In addition, the distribution of the co- seismic landslides also exhibits some diffusion that is different from general eases, likely associated with the seismic focus structure.展开更多
基金financed by the Research Foundation of SKLGP(Nos.SKLGP2015Z014,SKLGP2016Z013,SKLGP2016Z018)the SKLGP and CDUT for providing a scholarship to conduct a part of the reported research at the University of Arizona as a Visiting Research scholar
文摘This case study is about a landslide that occurred after 4 days of heavy rainfall,in the morning of June 29,2012,in Cengong County,Guizhou Province of China,geographical coordinated 108°20′-109°03′E,27°09′-27°32′N,with an estimated volume of 3.3×106 m3.To fully investigate the landslide process and formation mechanism,detailed geotechnical and geophysical investigations were performed including borehole drilling,sampling,and laboratory tests coupled with monitoring of displacement.Also,a combined seepage-slope stability modeling was performed to study the behavior of the landslide.After the heavy rainfall event,the sliding process started in this area.The landslide development can be divided into different parts.The man-made fill area,spatially distributed in the south side of the landslide area with low elevations,slid first along the interface between the slope debris and the strongly weathered bedrock roughly in the EW direction.Consequently,due to severe lateral shear disturbance,the slope in the main sliding zone slid next towards the SW direction,along the sliding surface developed within the strongly weathered calcareous shale formation located at a depth of 25-35 m.This means it was a rainfall triggered deep-seated landslide.Finally,retrogressive failure of a number of upstream blocks occurred,which moved in more than one direction.The initial failure of the man-made fill area was the‘engine’of the whole instability framework.This artificial material with low permeability,piled up in the accumulation area of surface and sub-surface and destroyed the drainage capacity of the groundwater.The numerical modeling results agreed with the analysis results obtained from the laboratory and field investigations.A conceptual model is given to illustrate the formation mechanism and development process of the landslide.
基金supported by the National Natural Science Foundation of China(grant No.41572194)the Institute of Geology,China Earthquake Administration(grant No.IGCEA1604)the National Key Basic Research Program of China(grant No.2013CB733205)
文摘Objective The 2014 Ludian Mw6.1 earthquake in Yunnan occurred in a mountainous area with complex tectonics and topography, which caused serious damage as well as co-seismic landslides of an unusual large scale. Because the suspected seismogenic faults on the surface, distribution of aftershocks and focal mechanism solutions are not consistent, it remains difficult to determine what is the real causal fault or seismogenic structure for this event. Actually, it may imply the complicity of the seismic source at depth. In addition, the distribution of the co- seismic landslides also exhibits some diffusion that is different from general eases, likely associated with the seismic focus structure.
