海水抽水蓄能电站上水库渗漏对地下水环境影响的数值模拟研究

Numerical simulation for the influence of the upper reservoir leakage on groundwater environment at the seawater pumped storage power station

海水抽水蓄能电站技术利用海水代替淡水,是解决电网调峰容量的有效途径,但是电站上水库的海水渗漏可能会造成库区下伏地下水的咸化污染。以珠海大万山岛为研究区,采用数值模拟方法,分别模拟了无防渗层、防渗层完好、防渗层库盆中心点渗漏、防渗层坝底渗漏四种不同渗漏的场景,讨论了海水抽水蓄能电站上水库渗漏对地下水环境的影响。结果表明:当没有防渗层时,入侵海水所形成的咸水带将污染地下水,渗漏最大深度达到60 m;当防渗层完好时,上水库海水几乎不发生渗漏;在防渗层中心点渗漏与坝底渗漏时,发生严重海水汇集的区域相对无防渗层有所缩小,但中心点渗漏的情况下,咸水带的分布范围较坝底渗漏情况下更大。因此在海水抽水蓄能电站的建设及运营期间,有必要对上水库作防渗处理,防止渗漏海水污染地下淡水;并对水库区域含水层中地下水盐分浓度进行实时监测,以便识别发生渗漏的区域,及时进行修复。

Seawater pumped storage power station technology using seawater instead of fresh water is an effective way to solve the peak load regulation capacity of power grid.However,the seawater leakage from the upper reservoir of the power station may cause salinization pollution of the underlying groundwater in the reservoir area.In this paper,taking Dawanshan island in Zhuhai as the research area,four different leakage scenarios are simulated by using numerical simulation method,including no impervious layer,intact impervious layer,seepage at the central point of impervious layer reservoir basin,and seepage at the bottom of impervious layer dam.The influence of leakage from upper reservoir of seawater pumped storage power station on groundwater environment is discussed.The results show that when there is no impervious layer,the salt water zone formed by seawater intrusion will pollute the groundwater,and the maximum depth of leakage is 60 m;when the impervious layer is intact,there is almost no leakage of seawater in the upper reservoir;when the seepage is at the center point of the impervious layer and at the bottom of the dam,the area where severe sea water collects is relatively small.In the case of central point leakage,the distribution range of saline water zone is wider than that of dam bottom leakage.Therefore,during the construction and operation of the seawater pumped storage power station,it is necessary to carry out anti-seepage treatment for the upper reservoir to prevent the leakage of seawater from polluting the underground fresh water;and to monitor the salt concentration of groundwater in the aquifer of the reservoir area in real time,so as to identify the leakage area and repair it in time.