大型人工输水渠道的高填方段在超常外力下一旦溃决，与一般行洪河道溃堤不同，会对渠道外区域造成非固有的灾难性影响。为防范这种无法用概率表征的潜在风险，需建立适宜的情景分析手段，以模拟与评估不同溃口规模下多种调控手段联合运用在应急处置中的有效性。利用中国水利水电科学研究院自主研发的洪涝仿真模型，通过改进立交河道计算单元的拓扑关系和退水闸模拟方式，建立了渠道一维、溃口流量及两岸二维同步耦合计算的溃堤洪水淹没模型。以某大型人工输水渠道典型高填方段为例，分类对比分析了不同溃口宽度、关闸时间和退水闸是否启用等共12种情景下的洪水淹没特征变化。结果表明：溃口宽度的增加对溃决洪水淹没范围和程度的影响较小；关闸时间越早，越可以有效减少淹没区的面积和水深，且在3 h内效果更明显；当地形和构筑物条件有利于洪水扩散时，及早关闸对淹没范围的减小幅度更大，反之，在洪水不容易扩散的区域，及早关闸对淹没水深的减小幅度更大；退水闸启用后对淹没的减轻作用与退水闸和溃口之间的相对位置和距离有关，位于溃口上游且距离越近时越有效。本项研究可为大型人工输水渠道制定或完善相应应急预案提供基本的手段和依据。

Different from the dike break of general rivers for discharging flood, the outburst flood from high-filled reaches of large-scale artificial water supply channel under supernormal external force would cause extrinsic catastrophic impacts on the outside area. In order to prevent this potential risk which is hard to be characterized using probability, scenario analysis method is needed to simulate and evaluate the effectiveness of combined application of various control measures under different breach scale in emergency disposal. Based on the existing flooding and water-logging simulation model developed independently by China Institute of Water Resources and Hydropower Research, the topological relation of calculation unit for crossed channels and simulation method for recession sluices were improved. A synchronous coupled dike-breaking flood inundation simulation model with one-dimensional model in channel, breach discharge calculation and two-dimensional model in both banks area of channel was built. Take a typical high-filled reaches of a large-scale artificial water supply channel as example, the change of flood inundation characteristic value was analyzed for 12 scenarios with different breach width, closing time for sluice gates and whether recession sluices were used. The results showed that the increase of breach width had less impact on inundation extent and degree of outburst flood; the earlier the closure time of sluice gates was, the better the decrease of inundation area and water depth was, and the effect was more obvious during the first 3 hours after dike-breaking happened; when the terrain and ground objects distribution were conductive to flood diffusion, closing sluice gate early could decrease more inundation area, otherwise, in areas where flood is not easy to spread, it was more effective for decrease of inundation depth; the mitigation function of recession sluice for inundation was relevant to the relative position and distance between the gate and breach, the sluice located in the upper stream of breach with closer distance was more effective to decrease the inundation. This study can provide basic method and basis for the formulation or improvement of corresponding emergency plans of large-scale artificial water supply channel.

TV68

国家重点研发计划课题资助(2018YFC1508003)；南水北调中线一期工程安全风险评估项目III标段——洪水风险评估(JZ0203A242016)