土石坝安全等级划分与防洪风险率评估  

Earth-rockfill dam safety classification and risk rate assessment on flood control

作　　者：姜树海[1] 范子武[1] 

机构地区：[1]南京水利科学研究院水文水资源与水利工程科学国家重点实验室,江苏南京210029

出　　处：《水利学报》2008年第1期35-40,共6页Journal of Hydraulic Engineering

基　　金：国家自然科学基金项目(5057903850679043);国家"十一五"科技支撑计划项目(2006BAC/4B03)

摘　　要：本文从土石坝安全等级评定和划分的有关规定出发,建立了防洪安全等级划分与风险概率的对应关系。根据风险率计算近似方法,校核率定了划分不同安全等级的风险率阈值和安全指数阈值,给出了不同安全等级土石坝的风险率区间,以实现大坝安全鉴定分级的定性评估与风险率定量计算的衔接。计算结果表明,土石坝的三种主要失事模式,包括洪水漫顶、滑坡失稳和渗流破坏,其安全等级划分的风险率阈值和安全指数阈值,大体维持在相同的水平上,略有差异。随大坝级别和安全等级的提高,风险率阈值减小,安全指数阈值相应增大。影响大坝安全的诸多不确定因素,包括水力、土力和水文等有关随机量的变异系数对安全阈值的影响较为显著。The correlation between safety classification and risk rate of flood control for earth-rockfill dams is established on the basis of relevant regulations of dam safety evaluation and classification.The thresholds of risk rate and safety indexes of risk rate as well as the safety index for safety classification are calibrated,and the ranges of dam risk rate for different levels are given by an approximate calculation method in order to achieve the joining of qualitative evaluation for dam safety classification and quantitative assessment for dam risk rate.The calculation results show that the thresholds of risk rate and safety index are at a similar level with a little difference for the three major accident modes of earth-rockfill dams,including flood overtopping,unstable landslide and seepage accident.With the elevating of the grade of dam and its safety level,the threshold of risk rate is decreased,while the threshold of safety index is increased accordingly.There is an obvious impact of the variability coefficient of stochastic variables,including the factors influencing the safety of dam such as hydraulic,soil mechanics and hydrologic factors,on the safety threshold.

关 键 词：大坝安全 防洪 风险率 安全指标 安全等级划分 风险率校核 

分 类 号：TV698.1[水利工程—水利水电工程]