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.