青海天峻新关角隧道涌排水水源识别与量化分析

Identification and quantitative analysis of groundwater discharged from New Guanjiao Tunnel in Tianjun, Qinghai

涌排水严重影响隧道施工与运行安全,查明隧道涌排水的来源,是隧道防水止水重要科学依据。青海天峻新关角隧道南北洞口处的地下水排水量分别为10021,60877 m^(3)/d,两者存在近50000 m^(3)/d的差异,涌排水量大,且来源不明。基于水文地质条件分析,分别采集了新关角隧道隧址区内大气降水、不同类型地下水和隧道出口涌排水水化学和氢氧稳定同位素样品。样品测试结果显示:新关角隧道北出口涌排水ρ(TDS)为0.44 g/L,^(2)H和^(18)O均值为-52.7‰,-8.3‰;南出口涌排水ρ(TDS)为0.85 g/L,^(2)H和^(18)O均值为-54.8‰,-8.5‰,隧址区基岩裂隙水ρ(TDS)为0.32~1.22 g/L,^(2)H和^(18)O均值为-55.77‰,-8.61‰;岩溶水ρ(TDS)为0.28~0.43 g/L,^(2)H和^(18)O均值为-50.92‰,-8.13‰,冻结层上水ρ(TDS)为0.26~0.48 g/L,^(2)H和^(18)O均值为-45.5‰,-7.6‰。对比分析认为:新关角隧道北出口涌排水主要来源于岩溶水,岩溶水占比为63%~80%,基岩裂隙水占20%~37%;新关角隧道南出口涌排水主要源于基岩裂隙水,基岩裂隙水占72%~88%,岩溶水占比12%~28%。涌水来源识别与水量,可为后期监测站点优化设置及隧道运行期止水工程实施提供科学依据。

Water inflow and drainage is one of the main factors affecting tunnel construction and safe operation.Finding out the source of groundwater inflow and drainage in tunnel is an important scientific basis for tunnel waterproof and water stop.The problem of water inflow and drainage of New Guanjiao Tunnel in Tianjun is serious.The groundwater discharge at the north outlet reaches 10021 m^(3)/d and the South outlet reaches 60877 m^(3)/d.There is a difference of nearly 50000 m^(3)/d in groundwater drainage.In order to find out the source of water inflow and drainage of Guanjiao tunnel and the reason for the great difference between the north and south water volume,we collecte the hydrogeochemical samples of the main groundwater and tunnel drainage in the tunnel based on the hydrogeological conditions.The results show that:the TDS of the drainage water at the north side of the tunnel is 0.44 g/L and the average hydrogen and oxygen isotopes are-52.7‰and-8.3‰;TDS of the southern tunnel drainage is 0.85 g/L and the isotopes is-54.8‰and-8.5‰;TDS of the crevice water is 0.32-1.22 g/L and the isotopes are-55.77‰and-8.61‰;TDS of the karst water is 0.28-0.43 g/L and the isotopes are-50.92‰and-8.13‰;TDS of the superpermafrost water is 0.26-0.48 g/L and the isotopes are-45.5‰and-7.6‰.The main drainage of the north tunnel comes from karst water,the karst water accounts for 63%-80%,the crevice water accounts for 20%-37%;The main drainage of the south tunnel comes from crevice water,the karst water accounts for 12%-28%,the crevice water accounts for 72%-88%.The identification of water inflow source and water quantity can provide a scientific basis for the optimal setting and the implementation of water stop project during tunnel operation.