土石坝服役风险及安全评估方法研究

发布时间：2018-01-23 06:09

本文关键词： 土石坝漫坝坝坡综合评估　出处：《南昌大学》2015年硕士论文　论文类型：学位论文

【摘要】：安全评估是土石坝工程中一个有难度且富有挑战性的重点研究领域。统计资料表明土石坝漫坝、渗流以及坝坡失稳是土石坝安全评估的主要因素。为此本文分析研究三种主要土石坝风险类型:漫坝风险、渗透破坏和坝坡稳定,并在此基础上,将土石坝工程作为一个整体,综合考虑各因素,对其进行安全综合评估。本文的主要研究内容有:(1)探讨了土石坝服役风险的成因,并利用故障树分析法,发展了土石坝风险成因辨识分析方法;基于故障树分析成果,运用粗集理论,提出土石坝服役风险成因数据挖掘方法。(2)分析了大坝漫坝风险定量评价方法,在求得漫坝概率的基础上,结合危险度转换赋值函数,将漫坝概率转换为漫坝危险度,并综合考虑大坝下游生命损失、经济损失及社会环境损失,计算大坝漫顶风险损失度;最后构建了漫坝风险指数的定量评价等级,为漫坝风险评价提供依据。(3)结合Geo-Studio分析软件中Seep/w渗流分析模块,对大坝进行渗流分析,分析大坝渗流的三种工况,即校核水位、正常蓄水位以及死水位工况,求得三种工况下的单宽渗流量、出逸比降及渗流逸出高程,并模拟得到不同工况下的浸润线。(4)提出了运用云模型和组合定权的二维评价模型对土石坝坝坡稳定性进行综合评价。结合层次分析与熵值法,提出了能同时顾及主客观权重的层次-熵耦合定权分析方法;依据云理论,利用云模型实现了定性定量不确定转换,能够反映评价过程中存在随机性与模糊性等不确定性难题;以模糊熵E作为辅助参评量,结合等级评价共同构建了土石坝坝坡稳定性的二维评价模型。(5)在分析整个土石坝安全系统的基础上,并从安全评估的角度,综合考虑了工程质量、运行管理、防洪安全、结构安全、渗流安全、地震安全以及金属结构的相关因素,构建了土石坝安全综合评价指标体系;确立了指标体系中定性与定量指标的等级量化标准;综合运用层次分析法与模糊分析理论,提出了基于系统多层次的土石坝安全模糊综合评价方法。
[Abstract]:Safety assessment is a difficult and challenging research field in earth-rock dam engineering. Seepage and dam slope instability are the main factors in the safety assessment of earth-rock dam. Therefore, this paper analyzes and studies three main risk types of earth-rock dam: dam overrun risk, seepage failure and dam slope stability, and on this basis. The earth-rock dam project as a whole is considered synthetically and the safety comprehensive evaluation is carried out. The main research content of this paper is: 1) the cause of the earth-rock dam service risk is discussed and the fault tree analysis method is used. The identification and analysis method of earth-rock dam risk is developed. Based on the results of fault tree analysis and using rough set theory, this paper puts forward the method of data mining for the cause of service risk of earth-rock dam, and analyzes the quantitative evaluation method of dam overrun risk, which is based on the calculation of dam overrun probability. Combined with the risk conversion assignment function, the probability of overtopping is converted to the risk of overtopping, and the risk loss degree of overtopping is calculated by taking into account the loss of life, economy and social environment in the downstream of the dam. Finally, the quantitative evaluation grade of risk index is constructed, which provides the basis for risk assessment of overfill dam. It is combined with Seep/w seepage analysis module in Geo-Studio analysis software. The seepage analysis of the dam is carried out, and the three working conditions of the dam seepage are analyzed, that is, check water level, normal storage water level and dead water level. The single wide seepage discharge, escape ratio drop and seepage escape height are obtained under three conditions. At the same time, the infiltration line under different working conditions is simulated. (4) A comprehensive evaluation of slope stability of earth-rockfill dam is proposed by using cloud model and two-dimensional evaluation model with combined weight, combined with analytic hierarchy process (AHP) and entropy method. A hierarchy entropy coupled weight analysis method is proposed, which can take into account the subjective and objective weights at the same time. According to the cloud theory, the qualitative and quantitative uncertain transformation is realized by using cloud model, which can reflect the uncertainty problems such as randomness and fuzziness in the evaluation process. Taking the fuzzy entropy E as the auxiliary evaluation quantity and combining the grade evaluation, the two-dimensional evaluation model of the slope stability of earth-rock dam is constructed. (5) based on the analysis of the whole safety system of the earth-rock dam, and from the point of view of safety assessment. The comprehensive evaluation index system of earth-rock dam safety is constructed considering the relevant factors of engineering quality, operation management, flood control safety, structure safety, seepage safety, earthquake safety and metal structure. The quantitative criteria of qualitative and quantitative indexes in the index system are established. Based on the analytic hierarchy process (AHP) and fuzzy analysis theory, a fuzzy comprehensive evaluation method for earth-rock dam safety is proposed.
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TV641;TV698.2

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