红坑子水库坝后渗流评估分析

Evaluation and Analysis of Seepage behind the Dam of Hongkengzi Reservoir

摘要: 红坑子水库坐落于新疆天山北坡达坂城东南低山丘陵，系引水灌注式小型水库承担下游0.23万hm²灌区灌溉用水任务，水库工程自建成蓄水运行15年来，为下游农业灌溉供水发挥了重要作用。本文针对水库工程多年运行以来，大坝坝后下游坝基渗流处于增大趋势是否正常安全问题，基于水库正常蓄水位和坝后坝坡出逸段及下游坝基表面的防渗与无防渗情况考虑，采用现场检验与计算复核方法进行了分析研究，结果表明，防渗情况下坝后最大出逸比降小于允许水力比降，不会发生渗透破坏；无防渗情况下最大出逸比降已显著大于允许水力比降，坝后渗流增加会发生渗透破坏，这说明了水库长期运行过程水库主坝和副坝防渗铺膜材料已发生了破损、撕裂情况，水库坝后渗流性态属于不安全运行状态。分析结果为进一步加强重视水库工程管护及工程除险加固提供了支撑。

Abstract: Hongkengzi reservoir is located in the low mountains and hills in the southeast of Dabancheng on the north slope of Tianshan Mountain in Xinjiang. It is a small-scale water diversion and perfusion reservoir that undertakes the irrigation water use task of 2300 hm² irrigation area in the downstream. Since the completion of the reservoir project and its operation for 15 years, it has played an important role in the agricultural irrigation water supply in the downstream. Based on the consideration of the normal water level of the reservoir, the seepage of the downstream dam foundation behind the dam and the seepage prevention and non seepage prevention of the downstream dam foundation surface since the operation, this paper analyzes and studies the seepage prevention of the dam foundation behind the dam with the method of on-site inspection and calculation review. The results show that the maximum escape ratio drop behind the dam is small under the seepage prevention condition. In the case of no seepage control, the maximum escape gradient is significantly greater than the allowable hydraulic gradient, and seepage damage will occur when the seepage behind the dam increases, which indicates that the impermeable membrane materials of the main dam and the auxiliary dam of the reservoir have been damaged and torn during the long-term operation of the reservoir, and the seepage behind the dam of the reservoir is unsafe. The analysis results provide support for further strengthening the management and protection of the reservoir project and strengthening the project.