【作者】 张鸿睿；

【导师】 司鹄；

【作者基本信息】 重庆大学 ， 工程（安全工程）（专业学位）， 2022， 硕士

【摘要】 为满足人们日益增长的美好生活需要,国家积极开发利用水利资源,促进了水库大坝建设蓬勃发展。然而,受自然条件、工程老化、管理不当等因素影响,水库大坝易发生安全事故,对周围群众的生命财产安全造成损害。研究水库大坝安全风险评估对水库大坝管理具有重要意义。本文针对其中分布最广的土石坝进行安全风险分析,运用改进CRITIC-G1组合赋权法和可变模糊集理论,研究土石坝安全风险评价模型。主要研究工作如下:(1)针对1954-2018年间我国登记在册的3541例溃坝事故进行统计,从大坝建设时期、溃坝坝型、溃坝原因等多角度分析影响溃坝的主要因素。统计结果表明:我国年溃坝率已显著降低,但水库大坝基数庞大,带病运行现象严重。其中,水库大坝主要事故为漫顶、失稳、渗流,各类事故的影响因素众多且存在耦合,利用事故树分析法对其进行辨识整合,将水库大坝事故影响因素分为运行管理、外部荷载、防洪能力、土体质量、结构与渗流、安全监测及其他金属结构等6类,提出了包括水位运行调度操作失误、水库超标准蓄水、坝高不足、有效泄量不足、填筑料质量差等在内的19个事故影响因素。(2)根据事故影响因素,建立土石坝安全风险评价指标体系。指标体系从运行管理、外部荷载、防洪能力、土体质量、结构与渗流、安全监测及其他金属结构等方面,提出了水库大坝管理人员数量、管理人员素质合格率、水利运行调度质量、水库大坝养护投入、大坝运行记录质量、历史洪水影响、高水位运行时长、年平均降雨量等31个指标。(3)基于土石坝安全风险评价指标体系,运用可变模糊集理论建立土石坝安全风险评价模型。模型运用改进CRITIC-G1组合赋权法确定各指标权重;引入可变模糊集理论,将土石坝安全风险划分为极高(Ⅰ级)、高(Ⅱ级)、中(Ⅲ级)、低(Ⅳ级)四个风险等级,并参考相关行业标准和理论研究,划分各指标风险等级模糊区间,计算等级隶属度和风险等级特征值,评估土石坝安全风险水平。(4)对深汕特别合作区两座土石坝进行安全风险评价。结果表明:甲土石坝风险度为2.7956,处于高风险状态。分析指标发现,甲大坝在安全责任人制度有效性、养护投入、年平均降雨量、土体渗透系数、监测项目覆盖率等指标方面的风险度均超过3.0,位于极高风险区域,极大提高了甲大坝的安全风险水平。乙土石坝整体风险度为1.7032,为中风险状态。乙大坝在大坝运行记录质量、年平均降雨量、坝高、历史洪水影响等部分指标上的风险度达到3.0及以上,表明乙大坝的安全风险水平控制主要受限于地区气候、坝型、历史资料缺失等因素。评价结果与工程实际情况相符合,验证了评价模型的可行性和有效性。更多还原

【Abstract】 In order to meet people’s growing needs for a better life,the state actively develops and utilizes water conservancy resources and promotes the vigorous development of reservoir and dam construction.However,due to factors such as natural conditions,project aging,and improper management,reservoir dams are prone to safety accidents,causing damage to the lives and properties of surrounding people.The study of reservoir dam safety risk assessment is of great significance to reservoir dam management.This paper analyzes the safety risk of reservoir dams in operation,and uses the improved CRITIC-G1 combined weighting method and variable fuzzy set theory to study the safety risk assessment model of reservoir dams.The main research work is as follows:(1)Based on the statistics of 3541 dam failure accidents registered in China from1954 to 2018,the main factors affecting dam failure are analyzed from multiple perspectives such as dam construction period,dam failure type,and dam failure reasons.:The annual dam break rate in China has been significantly reduced,but the reservoir dam base is huge,and the phenomenon of operation with diseases is serious.Among them,the main failure accidents of reservoir dams are overtopping,instability and seepage.There are many influencing factors of various accidents and they are couplings.Using fault tree analysis to identify and integrate them,the influencing factors of reservoir dam accidents are divided into six categories: operation management,external load,flood control capability,soil quality,structure and seepage,safety monitoring and other metal structures.There are 19 accidents factors including wrong decision-making,super-standard water storage in reservoirs,insufficient dam height,insufficient effective discharge,poor fill quality and some others.(2)According to the accident influencing factors,combined with industry norms and standards and engineering monitoring projects,a earth-rock dam safety risk evaluation index system is established.Proposed from the aspects of operation management,external load,flood control capacity,soil quality,structure and seepage,and safety monitoring and other metal structures,the index system includes 31 indicators such as the number of reservoir dam managers,the qualification rate of dam managers,the quality of water conservancy operation and dispatch,the investment in reservoir dam maintenance,the quality of dam operation records,historical floods,high water level operation time,annual average rainfall and some others.(3)Based on the earth-rock dam safety risk evaluation index system,the variable fuzzy set theory is used to establish a earth-rock dam safety risk evaluation model.The improved CRITIC-G1 combined weighting method is used to determine the weight of each index.The model introduces variable fuzzy set theory and divides the safety risk of earth-rock dams into extremely high(level I),high(level II),medium(level III),and low(Level IV)risk level.By referring to relevant industry standards and theoretical research,the fuzzy interval of risk level of each index is divided.Then,the rank membership degree and the characteristic value of the risk level are calculated to evaluate the safety risk level of the earth-rock dam.(4)Safety risk assessment was carried out for two earth-rock dams in the Shenshan Special Cooperation Zone.The results show that the risk degree of earth-rock dam A is2.7956,which means it is in a high-risk state.The analysis of indicators found that the risk degree of dam A in some indicators exceeds 3.0,and it is located in a very high-risk area,including the quality of the safety responsible person system,maintenance investment,annual average rainfall,soil permeability coefficient,monitoring project coverage and some others,which has greatly improved.dam A’s safety risk level.The overall risk degree of the earth-rock dam B is 1.7032,which is a medium risk state.The risk level of Dam B in some indicators such as dam operation record quality,annual average rainfall,dam height,and historical flood impact reached 3.0 or above,indicating that the control of the safety risk level of Dam B is mainly limited by the regional climate,dam type,lack of historical data and other factors.The evaluation results are consistent with the actual situation of the project,which verifies the feasibility and effectiveness of the evaluation model.更多还原