Analysis And Assessment On Risk For Reinforced Levee Of Reservoir

In this paper, the risk for reinforced levee of plain reservoir is mainly studied. The probability-and-reliability-based risk analysis procedure is applied in safety assessment of levees, and this dissertation presents a groping study on foundations, models, approaches and applications of risk analysis for levees failures, and the safety of reservoir is evaluated with the method of fuzzy comprehensive assessment.The typical process of risk analysis is summaried in the paper; Based on referring on large numbers of correlative literature at home and abroad, fault tree analysis (FTA) is adopted to analyze the failure types of levee reaches, and failure modes of levee reaches are classified into seepage failure mode, and slide instability failure mode; Meanwhile an illustration to calculating model for each failure mode are described in detail, and a discretized method for integral formula of calculating models is proposed; Furthermore, methods for estimating value of standard deviation of random variables are also discussed. The results are suggested to be donated with nonlinear curve of risk and water level to express the safety of levee better.Based on real conditions of one plain reservoir, the risk models of seepage failure mode, and slide instability failure mode are founded after the analysis of failure mode; In allusion to the characteristic of each failure mode, calculating approaches for conditional probability of each failure mode are presented; With reliability analysis theory, risk value of the levee are evaluated by using Monte-carlo Method, and the calculating result is also analyzed subsequently.Finally, based on the research achievement of durability assessment in and abroad, this paper will set up a three-grade fuzzy comprehensive assessment model which is based on analytical hierarchy process (AHP), then divide the assessment factors to four grades and adopt the trapeziform subordinate function to ascertain the subordinate degree to each grade of durability assessment for structure properties; when the primary weight value of each factor is ascertained, the fuzzy comprehensive assessment outcome will be analyzed to ascertain the subordinate degree.The foundation of math mode on risk analysis of each failure mode and safety assessment system in the paper can be use for reference by analogous projects, and also applied to designs of dam projects and risk decision-making of safety assessment, which holds high value as reference to other analogous projects.