暗河发育区隧道选线与突涌水灾害预控分析

Tunnel Route Selection and Water Inrush Precontrol Analysis for Underground River Development Areas

为控制隧道穿越暗河发育区突涌水风险,通过对中国21例隧道穿越暗河发育区突涌水工程实例的统计分析,研究暗河发育规律和地质判识特征,提出"横向查延伸-竖向定标高-洞内探位置"的三阶段暗河识别方法和隧道穿越暗河发育区选线原则;研究隧道穿越暗河发育区突涌水的孕灾环境和致灾因子,遴选出隧道突涌水的主要影响因素,建立隧道穿越暗河发育区突涌水风险评估层次模型,确定评价指标的权重,开展暗河发育区隧道选线与突涌水灾害预控分析研究。研究结果表明:提出的三阶段暗河识别方法综合采用地质勘察、工程类比、示踪试验、物理探测等方法,可依次确定暗河流向、暗河水位、暗河与隧道空间位置关系;暗河发育强度、暗河水流量、暗河与隧道的空间位置是隧道穿越暗河区突涌水风险的主控因素,其次为超前地质预报、暗河形态、暗河坡度,最后为前兆信息、监控量测、开挖支护。研究成果在利万高速齐岳山隧道德胜场暗河的识别与风险评估中得到了成功应用,验证了暗河识别和突涌水风险评估方法的合理性与可行性,对类似穿越暗河发育区隧道工程建设具有一定的借鉴意义和参考价值。

To control the risk of water inrush in a tunnel passing through an underground river development area, 21 cases of water inrush engineering were collected and analyzed. The development law and geological identification characteristics of an underground river were studied. A three-stage underground river identification method was proposed, which involved searching the extension of the river in the horizontal direction, confirming the elevation of the river in the vertical direction, and detecting the relative location of the river in the tunnel. Further, route selection principles when a tunnel passed through an underground river development area were defined. The influence factors of the hierarchical assessment model for water inrush were selected and the weight of the factors were obtained. Tunnel route selection and water inrush precontrol in underground river development areas were studied. The results show that the three-stage underground river identification method is a synthetic method of geological survey, engineering analogy, tracer testing, and geophysical prospecting, which can successively verify the flow direction, elevation of the underground river, and relative position of the underground river and the tunnel. The assessment results show that the main control factors of water inrush risk in the underground river area are development intensity, water flow, relative position of the underground river and the tunnel. The less significant factors include advance geological forecast, development forms of the underground river, and hydraulic gradient of the underground river. And the least important factors include precursory information, monitoring measurement, and tunnel excavation and support. The research findings were successfully applied to the identification and risk assessment of Deshengchang underground river at Qiyueshan Tunnel site on the line of Lichuan-Wanzhou Expressway, and the subsequent results prove that the proposed method is rational and feasible, and it can provide a reference for similar engineering activities.