高拱坝施工初-中期导流风险模型及应用

面向工程设计阶段，采用高拱坝施工动态仿真技术获取施工初-中期挡水度汛面貌数据，综合考虑水文、水力随机性因素，构建高拱坝施工初-中期导流风险模型，提出采用Monte Carlo方法耦合挡水度汛面貌数据和主要随机因素进行风险模型求解的方法。基于风险分析原理提出了导流洞设计的风险判别方法，给出导流洞尺寸设计优化的数学模型和具体步骤。通过金沙江上游某高拱坝工程案例分析的结果表明:所提风险模型及求解方法是适用的、有效的，该模型能够得到整个施工初-中期导流风险率，较为客观地反映高拱坝施工中期度汛可能存在的两种挡水情况，克服了初期导流风险模型的局限性；施工中期导流风险率随导流洞尺寸增大而减小，导流洞尺寸设计的可行方案集存在界限，即优化方案。研究成果可为高拱坝施工导流的风险决策和设计优化提供理论支撑。

Risk model of flow diversion in the initial through middle stages for high arch dam construction and its application

The diversion tunnel of high arch dam located in canyon areasruns through the initial to middlestages of dam construction. Investigating the creation and solution of a diversion risk model of the initial and middle stages of high arch dam construction is therefore important to the design optimization of diversion tunnels. The present work focuses on the engineering design stage and makes use of the dynamic simulation technology of high arch dam construction to collect morphological data covering water retaining and dam protection from the initial to middle stages of construction. We here established a risk model of flow diversion in the initial through middle stages for high arch dam construction considering the factors of hydrology and hydraulic randomness,and a method of solving the risk model using Monte Carlo method,which couples with the water retaining and dam protection morphological data and the major random factors,is proposed in this work. Based on the principle of risk analysis,a risk recognition method for the design of diversion tunnel is proposed,and the mathematical model and detailed steps for the design optimization of diversion tunnel dimensions are given. The results of the case study of a high arch dam in the upper reaches of Jinsha River show that the proposed risk model and the solution method are applicable and effective;the model can be used to determine the risk rate of the initial to middle stages of the entire construction project,and it can objectively reflect the two possible water retaining conditions of the high arch dam during the middle stage of the dam protection period and overcome the limitations of the initial diversion risk model;during the middle stage of construction,the diversion risk rate decreases with the increase in diversion tunnel dimensions;and the feasible scheme set of diversion tunnel dimension designs has a boundary,i. e. the optimal scheme. The outcomes of this study can provide theoretical support for risk decision-making and design optimization for the construction of diversion structures for high arch dams.