A characteristic rainfall is introduced to overcome the difficulties encountered in determining a critical rainfall value for triggering debris flow.The characteristic value is defined as the rainfall at which debris-...A characteristic rainfall is introduced to overcome the difficulties encountered in determining a critical rainfall value for triggering debris flow.The characteristic value is defined as the rainfall at which debris-flow occurrence probability shows a rapid increase,and can be used as a warning rainfall threshold for debris flows.Investigation of recorded debris flows and 24-hour rainfall data at Jiangjia basin,Yunnan Province,in southwestern China,demonstrates the existence of such a characteristic rainfall.It was found that the characteristic rainfall corresponds to the daily rainfall of 90% cumulative probability by analyzing the basin's daily rainfall histogram.The result provides a simple and useful method for estimating a debris-flow warning rainfall threshold from the daily rainfall distribution.It was applied to estimate the debris-flow warning rainfall threshold for the Subaohe basin,a watershed in the 2008 Wenchuan earthquake zone with many physical characteristics similar to those of the Jiangjia basin.展开更多
Rainfall erosivity is defined as the potential of rain to cause erosion.It has great potential for application in studies related to natural disasters,in addition to water erosion.The objectives of this study were:ⅰ)...Rainfall erosivity is defined as the potential of rain to cause erosion.It has great potential for application in studies related to natural disasters,in addition to water erosion.The objectives of this study were:ⅰ)to model the Rday using a seasonal model for the Mountainous Region of the State of Rio de Janeiro(MRRJ);ⅱ)to adjust thresholds of the Rday index based on catastrophic events which occurred in the last two decades;andⅲ)to map the maximum daily rainfall erosivity(Rmaxday)to assess the region's suscepti-bility to rainfall hazards according to the established Rday limits.The fitted Rday model presented a satisfactory result,thereby enabling its application as a Rday estimate in MRRJ.Events that resulted in Rday>1500 MJ ha-1.mm.h-1.day-1 were those with the highest number of fatalities.The spatial distribution of Rmaxday showed that the entire MRRJ has presented values that can cause major rainfall.The Rday index proved to be a promising indicator of rainfall disasters,which is more effective than those normally used that are only based on quantity(mm)and/or intensity(mm.h-1)of the rain.展开更多
A set of soil collapse prediction and prevention swtem for railway slopes is builtis this paper. Based on the field investisation, Oreen-Ampt model, the quantitytheory and computeraided decision-making sgutem, convere...A set of soil collapse prediction and prevention swtem for railway slopes is builtis this paper. Based on the field investisation, Oreen-Ampt model, the quantitytheory and computeraided decision-making sgutem, convereion tables ofworking rainfall ,grading tables of resistant ability to rainfall, and the warningrairifall levels are made, forming the chief part of a practical computer-aideddecisionmaking system. Usins the system, the danser degree of railway slopescan be predicted, and the reinforcins ensineerins and the flood control workcan also be arranged ratiofially.展开更多
基金funded by the National Program on Key Basic Research Project (973 Program) (Grant No. 2008CB425802)the Knowledge Innovation Program of Chinese Academy of Sciences (Grant No. KZCX2-YW-302)the National Natural Science Foundation of China (Grant No. 40701014)
文摘A characteristic rainfall is introduced to overcome the difficulties encountered in determining a critical rainfall value for triggering debris flow.The characteristic value is defined as the rainfall at which debris-flow occurrence probability shows a rapid increase,and can be used as a warning rainfall threshold for debris flows.Investigation of recorded debris flows and 24-hour rainfall data at Jiangjia basin,Yunnan Province,in southwestern China,demonstrates the existence of such a characteristic rainfall.It was found that the characteristic rainfall corresponds to the daily rainfall of 90% cumulative probability by analyzing the basin's daily rainfall histogram.The result provides a simple and useful method for estimating a debris-flow warning rainfall threshold from the daily rainfall distribution.It was applied to estimate the debris-flow warning rainfall threshold for the Subaohe basin,a watershed in the 2008 Wenchuan earthquake zone with many physical characteristics similar to those of the Jiangjia basin.
基金We acknowledge the Coordination of Superior Level Staff Improvement-CAPES[grant number 88882.306661/2018-01]the National Council for Scientific and Technological Development-CNPQ[grant number 301556/2017-2]for supporting and funding this work.
文摘Rainfall erosivity is defined as the potential of rain to cause erosion.It has great potential for application in studies related to natural disasters,in addition to water erosion.The objectives of this study were:ⅰ)to model the Rday using a seasonal model for the Mountainous Region of the State of Rio de Janeiro(MRRJ);ⅱ)to adjust thresholds of the Rday index based on catastrophic events which occurred in the last two decades;andⅲ)to map the maximum daily rainfall erosivity(Rmaxday)to assess the region's suscepti-bility to rainfall hazards according to the established Rday limits.The fitted Rday model presented a satisfactory result,thereby enabling its application as a Rday estimate in MRRJ.Events that resulted in Rday>1500 MJ ha-1.mm.h-1.day-1 were those with the highest number of fatalities.The spatial distribution of Rmaxday showed that the entire MRRJ has presented values that can cause major rainfall.The Rday index proved to be a promising indicator of rainfall disasters,which is more effective than those normally used that are only based on quantity(mm)and/or intensity(mm.h-1)of the rain.
文摘A set of soil collapse prediction and prevention swtem for railway slopes is builtis this paper. Based on the field investisation, Oreen-Ampt model, the quantitytheory and computeraided decision-making sgutem, convereion tables ofworking rainfall ,grading tables of resistant ability to rainfall, and the warningrairifall levels are made, forming the chief part of a practical computer-aideddecisionmaking system. Usins the system, the danser degree of railway slopescan be predicted, and the reinforcins ensineerins and the flood control workcan also be arranged ratiofially.
