深埋长距离输水隧洞涌水量分析及不同工况计算方法研究

Water Inflow Analysis of a Deeply Buried Long-Distance Water Conveyance Tunnel and Calculation Methods under Different Working Conditions

摘要: 深埋长距离输水隧洞涌水量受水文地质条件、施工方式与季节水位等多因素耦合影响，涌水量预测方法选取不当易造成排水系统规模不足或投资浪费。本文以某深埋长距离输水隧洞工程为背景，在总结工程地质条件与涌水特征的基础上，将涌水量分析划分为一般基岩裂隙水、断层破碎带、岩溶富水、软弱破碎围岩、高外水压力及竖井–平洞交汇等六类水文地质工况，并按施工阶段与季节水位细化边界条件；结合工程实际与已有研究成果，建立了不同工况下经验公式法、理论解析法与数值模拟法的比选原则，提出了“多方法包络 + 实测反演 + 动态修正”的涌水量计算优化与现场校核流程。结果表明：一般基岩段可采用经验公式与解析法快速估算，断层、岩溶、竖井–平洞交汇及一洞双TBM掘进段宜采用三维非稳定数值模拟，富水软弱破碎围岩段宜采用渗流–应力–支护耦合分析，变坡与反坡施工段应以最大涌水量包络值控制泵站与排水系统设计；丰水期高水位工况应作为最大涌水量与衬砌外水压力的控制工况。研究成果可为同类深埋长隧洞涌水量预测、排水系统设计及注浆堵水参数优化提供参考。

Abstract: Water inflow of deeply buried long-distance water conveyance tunnels is jointly affected by hydrogeological conditions, construction methods and seasonal groundwater levels, and improper selection of prediction methods may lead to insufficient drainage capacity or waste of investment. Based on a deeply buried long-distance water conveyance tunnel project, this paper summarizes its engineering geological conditions and water inflow characteristics, and classifies the water inflow analysis into six hydrogeological working conditions, i.e., general bedrock fissure water, fault fracture zones, karst water-rich sections, weak broken surrounding rock, high external water pressure and shaft-adit intersections, with the boundary conditions further refined according to construction stages and seasonal water levels. Combined with engineering practice and previous studies, a comparison and selection principle among the empirical formula method, analytical method and numerical simulation under different working conditions is established, and an optimization and verification procedure for water inflow calculation is proposed, which combines “multi-method enveloping, field measurement inversion and dynamic correction”. The results show that empirical formulas and analytical methods can be used for rapid estimation in general bedrock sections; three-dimensional transient numerical simulation is preferable for fault, karst, shaft-adit intersection and one-tunnel-double-TBM excavation sections; seepage-stress-support coupling analysis is required for water-rich weak broken surrounding rock; and the maximum water inflow envelope should be adopted to control the design of pumping stations and drainage systems in slope-change and adverse-slope construction sections. The high-water-level condition in the wet season should be regarded as the controlling case for the maximum water inflow and the external water pressure acting on linings. The results can provide a reference for water inflow prediction, drainage system design and grouting parameter optimization of similar deeply buried long tunnels.