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
Predicting the failure time of a landslide is considered as challenging work in the field of landslide research,and inverse velocity is proved to be an effective and convenient method.The onset of acceleration(OOA)has...Predicting the failure time of a landslide is considered as challenging work in the field of landslide research,and inverse velocity is proved to be an effective and convenient method.The onset of acceleration(OOA)has a crucial effect on the prediction failure time from the inverse velocity method.However,a simple method to identify OOA points is lacked,and most of the identifications rely on expert experience.Therefore,this study presents an application of a simple framework developed to identify the OOA by analyzing monitoring velocity data in three steps,including selection of the absolute value of velocity,reliable area identification and OOA identification.A new parameter based on exponential moving average(EMA)is developed to identify the landslide OOA.The framework is applied to three historical case studies to test its practicability and effectiveness.The forecasting results show a good correspondence between the accuracy rate and the coefficient of determination(R2).The predicted failure time according to the linear extrapolation starting from the identified OOA points is acceptable with a high R2 and high accuracy.展开更多
Long-term stability of large span caverns is earnest but poorly understood in preservation of cultural relics.The life span of huge caverns is difficult to extrapolate from short period of monitoring or laboratory tes...Long-term stability of large span caverns is earnest but poorly understood in preservation of cultural relics.The life span of huge caverns is difficult to extrapolate from short period of monitoring or laboratory testing.A huge ancient quarry with 21 caverns whose original status is well kept over 1400 years was found in Tiantai County of South China.One of the caverns has an 81 m span which is far beyond the 50 m expectation on current knowledge.The tension at the core of long stability is the excavation speed versus deliberation.Here we show a unique technique of Digging Holes for Quarrying Vertical Flagstone(DQF)invented by ancestors to ensure the safety,which is much smarter compared to blasting and casting technique that commonly used after the Industrial Revolution.展开更多
Quarry induced collapse,an issue of particular concern in the mining industry,is a typical form of manmade disaster.Identification of the morphological characteristics of such collapses is commonly based on seismic re...Quarry induced collapse,an issue of particular concern in the mining industry,is a typical form of manmade disaster.Identification of the morphological characteristics of such collapses is commonly based on seismic records but comprehensive studies regarding the mechanism and energy conversion mode utilizing the seismic record is seldom undertaken.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funded by the National Natural Science Foundation of China(Grant NO.41772324)the Open Foundation of Chengdu Center of China Geological Survey。
文摘Predicting the failure time of a landslide is considered as challenging work in the field of landslide research,and inverse velocity is proved to be an effective and convenient method.The onset of acceleration(OOA)has a crucial effect on the prediction failure time from the inverse velocity method.However,a simple method to identify OOA points is lacked,and most of the identifications rely on expert experience.Therefore,this study presents an application of a simple framework developed to identify the OOA by analyzing monitoring velocity data in three steps,including selection of the absolute value of velocity,reliable area identification and OOA identification.A new parameter based on exponential moving average(EMA)is developed to identify the landslide OOA.The framework is applied to three historical case studies to test its practicability and effectiveness.The forecasting results show a good correspondence between the accuracy rate and the coefficient of determination(R2).The predicted failure time according to the linear extrapolation starting from the identified OOA points is acceptable with a high R2 and high accuracy.
基金support by the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection(SKLGP2011K007)Chengdu University of Technology,the Key Research Program of the Chinese Academy of Sciences(KZZD-EW-05-02)+2 种基金by the National Natural Science Foundation of China(NSFC)(Nos.40972198,41172269)support is also from the Chinese Special Funds for Major State Basic Research Project under Grant No.2010CB732001Help provided by Master Chang Shen,Long Fu of Heidong CiEn Temple,and Mr.He Wantong during field investigations is thankfully acknowledged.
文摘Long-term stability of large span caverns is earnest but poorly understood in preservation of cultural relics.The life span of huge caverns is difficult to extrapolate from short period of monitoring or laboratory testing.A huge ancient quarry with 21 caverns whose original status is well kept over 1400 years was found in Tiantai County of South China.One of the caverns has an 81 m span which is far beyond the 50 m expectation on current knowledge.The tension at the core of long stability is the excavation speed versus deliberation.Here we show a unique technique of Digging Holes for Quarrying Vertical Flagstone(DQF)invented by ancestors to ensure the safety,which is much smarter compared to blasting and casting technique that commonly used after the Industrial Revolution.
基金support provided by the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection(SKLGP2011K007)the Key Research Program of the Chinese Academy of Sciences(KZZDEW-05-02)+1 种基金by the National Natural Science Foundation of China(NSFC)(Nos.41372324,41172269)support from the Chinese Special Funds for Major State Basic Research Project under Grant No.2014CB046901.
文摘Quarry induced collapse,an issue of particular concern in the mining industry,is a typical form of manmade disaster.Identification of the morphological characteristics of such collapses is commonly based on seismic records but comprehensive studies regarding the mechanism and energy conversion mode utilizing the seismic record is seldom undertaken.
