大清河系观测河段及南水北调 中线方案冰情计算分析①

为研究南水北调中线方案总干渠冰期输水问题，通过对大清河系冰情分析、水位水温验证计算及冰情影响计算表明：建立的一维非恒定水力学和水温数学模型可行且验证精度较高；观测河段无冰盖时糙率为０．０２～０．０３，有冰盖时糙率增加到０．０３～０．０４；假定不出现冰情，观测河段水位将下降０．１～０．４ ｍ ，过流能力将提高３０％ ～６５％ 。总干渠与大清河冰情对比分析表明：冬季冰期输水期间，总干渠可以不考虑岸冰和底冰，并且难以形成静态稳定冰盖，水内冰、水面流冰、冰塞和冰坝的出现和存在将不同程度上影响总干渠的糙率、水位和输水能力。

Calculation and Analysis of Ice Processes in Observed Reaches of Daqinghe River and in Main Channels of Middle-Line Scheme of Water Transfe r Project from South to North China

In order to study transferring water problems during ice period for the main channels of Middle Line scheme of Diversion Project from South to North,through analysis of ice conditions from field data of the Daqinghe River,verification calculations for water stages and water temperatures,calculations and analyses of effect of ice conditions were performed .The study results show that the established 1 D unsteady mathematical model simulating hydraulics and water temperature is feasible ,the accuracy of verification is satisfied receptable.River roughness without ice cover in the observed river reaches is 0.02-0.03,and it reaches 0.03-0.04 during the period of ice cover.If the ice conditions were not considered,the water levels in the observed river reaches would be reduced by 0.1-0.4 m and the discharge capacities,increased by 30%-65%.Comparative analysis of ice condition between the main channels and Daqinghe river show that during water transfer in winter with ice conditions,bank ice and battom ice may not be considered,stable static ice cover could hardly be formed ,and the occurrence and existence of ice fragile,ice floe,ice jam and ice dam would effect channel roughnesses,water stages and capacities of water transfer to some extent.