大瑞铁路保山隧道建设对易罗池岩溶水系统影响研究

Effects of Baoshan Tunnel Excavation on Yiluo Lake Karst Water System

大瑞铁路保山隧道为穿越保山盆地和怒江峡谷间的越岭隧道,易罗池泉水为保山盆地西侧边缘岩溶大泉。通过区内地质构造、地层岩性和水动力条件的分析,对易罗池岩溶水系统形成机制进行研究,认为易罗池岩溶水系统沿大宝盖向斜灰岩夹层发育,补给源位于向斜西翼沙河上游朝阳寨一带地表沙河水,沿灰岩夹层管道径流,于易罗池排泄,具一定的承压性,为典型埋藏型岩溶。通过分析保山隧道区与岩溶水间的水力关系,认为保山隧道揭示岩溶管道水可能性较小,隧道施工穿过向斜西翼的灰岩夹层,形成低势面后可能将会对岩溶水系统水压有一定影响,设计和施工在向斜西翼灰岩夹层段采取技术成熟的封堵地下水措施,可有效规避工程风险。

The Baoshan tunnel on Dali-Ruili railway is seated between Baoshan basin and Nujiang river valley, passing through mountain area. The Yiluo Lake Spring is developed in the Karst water system and located in the west of Baoshan basin. For the purpose of avoiding engineering risk, this paper studies the formation mechanism of Yiluo Karst water system, analyzes the Karst hydraulic relationship of the Baoshan tunnel, evaluates the effects of Baoshan tunnel excavation on the Yiluo Lake Karst water system, as well as the rationality of proposed engineering measures. The Yiluo Karst water system is typically buried in Karst, develops in the limestone sandwich in the Dabaogai syncline, and supplemented with the upstream sand river water situated in Chaoyang village of the west of the syncline, runoffs among the limestone sandwich and discharges to the Yiluo Lake. The water system is characterized by confined water. The Baoshan tunnel is constructed through the limestone sandwich of the west of syncline, forming low surface with certain impact on the Karst system water pressure but with less reveal of the Karst water pipe. In order to avoid the engineering risk effectively, the research recommends such measures as well-established blocking ground water technique in the limestone sandwich of the west of syncline in the process of design and construction.