某水库岩溶管道对库区蓄水的影响分析

Effect Analysis of Karst Pipelines in a Reservoir to Reservoir Area Water Storage

根据现场水文地质条件和岩溶的调查分析,确定水库坝址区有5条岩溶管道。水库运行期的库水位高于管道高程,在水位差作用下,库水会沿管道向库区外排泄,可能产生岩溶塌陷、岩溶管道渗漏等环境水文地质问题,影响水库正常蓄水。基于库区水文地质条件和岩溶发育规律,建立了岩溶区三维地下水流运动的数值模型,利用实测水位和计算水位反演,确定了岩溶-裂隙介质和岩溶管道的渗透系数。采用验证后的模型对库区蓄水后的地下流场和岩溶管道渗漏量进行分析计算,得出了坝址区5#岩溶管道处渗漏量较大的结论,并针对岩溶管道提出了相应的防渗措施。

Five karst pipelines are delermined in reservoir dam area according to the survey and analysis of field hydrogeological conditions and karst. During the operation period of reservoir, when the water level of reservoir exceeds the pipeline elevation , under the effect of water level difference, the water in reservoir will drain to out of the reservoir along karst pipelines, which may bring the environmental hydrogeology problems, such as karst collapse, karst pipelines leakage, that will impact the reservoir depositing water nomally. A three-dimensional numerical model of groundwater flow movement in karst area is established based on the hydrogeological conditions and the rule of karst development of reservoir area. The permea- bility coefficient of karst-fractured medium and pipelines are determined by the measured water level and inversion of calculated water level. Finally, the underground flow field and the seepage quantity of karst pipeline are analysed and calculated by using the validated model after water storage in the reservoir area. The conclusion shows the leakage quantity is large at 5# karst pipeline of the dam area. And the corre-sponding seepage prevention measures for karst pipeline are put forward.