高堆石坝施工挡水风险的时变性和填筑进度的不确定性增加了坝体施工期度汛方案决策的难度。针对高堆石坝施工度汛过程动态变化的特点,随机模拟大坝挡水风险,并将其划分3个风险状态以判断度汛行动。以整个度汛施工期成本最小化为目标,考虑洪水来流、填筑进度和决策成本等关键因素,建立基于马尔科夫过程的高堆石坝施工度汛决策模型,分析逐月大坝挡水风险状态下的度汛策略、成本函数和风险状态转移概率。在检验其马尔科夫特性基础上,采用决策迭代算法求解每一决策时刻状态下的最优施工度汛方案及度汛过程的决策路径。工程实例分析表明,该决策模型对高堆石坝施工度汛计划策略的调控结果符合实际施工度汛高程变化情况,为指导快速准确制定大坝施工度汛方案提供了参考。

Time variation of water-retaining risk and uncertainty of filling progress aggravate the difficulties in making decision for high rock-fill dam construction in flood period. Accordingly, the water retaining risk of high rock-fill dam was calculated by stochastic simulation, and then was classified into three risk states which could indicate the decision actions. With the objective of minimizing the cost of the entire construction process in flood season, the critical factors such as incoming flood flow, filling schedule and cost of decisions were taken into account to build a decision-making model based on Markov Processes. By using this model, the flood prevention strategies, cost functions and transfer probability for each risk degree were analyzed. After testing the Markov property, the optimal strategy for each state at current time and a sequential risk decision path in this process can be predicted by strategy iteration method. A study case shows that the adjustment results by the proposed model consists well with the actual construction plan change for water retaining elevation. The results offer reference for timely and accurate flood prevention scheme in construction period.