Research on hydrogen and oxygen isotope of leakage in branch construction tunnel of Tianhuangping Pumped-storage Station

The leakage occurs frequently and relatively centralized in the water-carriage system under the action of the high water head pressure since Tianhuangping Pumped-storage Station operated. The stability of the surrounding bedrock leakage under the long-term action of the high water head pressure receives much concern. This paper studies the water leakage in the branch construction tunnel in the water-carriage system of THP Station by the hydrogen and oxygen isotope analysis method combined with the inorganic hydrochemistry analysis method. The results shows that the value of δ D in the leakage water has obvious zonality and then is grouped in four types. What's more, the concentration of the δ 18O is relatively enriched, mainly produced from the isotopic fractionation caused by the interaction of the calcium hydroxide and soft water in the bulkhead concrete of the branch construction tunnel.