西南岩溶区深埋隧洞水文地质概念模型及突涌水研究

针对岩溶地区复杂的水文地质条件,以建立岩溶区域水文地质概念模型和隧洞涌水预测方法为目标,通过分析贵州夹岩水利枢纽工程深埋长引水隧洞工程区的岩溶水文地质资料,结合地层结构、岩性组合、地貌特征等因素,研究该工程区内岩溶地下水的补给、径流、排泄关系。在此基础上,依托实地调查的典型涌水支洞,分析研究了不同情形下涌水量对降雨事件的响应,总结得出岩溶隧洞突涌水模式。针对不同突涌水模式的特点,提出了相应的涌水量计算方法与处理措施。结果表明:岩溶隧洞突涌水模式可以分为岩溶管道控水模式、层面控水模式和断层带与暗河联合控水模式;岩溶管道控水的猫场隧洞4#支洞涌水对降雨响应迅速,宜采用水均衡法估算涌水量,层面控水的水打桥隧洞2#支洞涌水受岩体渗透各向异性影响较大,宜采用岩体渗透性各向异性的有限元渗流分析方法预测,而断层带与暗河联合控水的水打桥隧洞4#支洞涌水主要由断层从暗河导入,可采用三维有限元渗流场计算分析预测其涌水;采用上述方法对典型支洞涌水预测的误差分别为6.97%、4.81%、1.13%。研究成果对于岩溶区深埋隧洞工程的建设具有一定借鉴意义。

Hydrogeological conceptual model and study on water inrush of deep-buried tunnel in karst area of Southwest China

Aiming at the complicated hydrogeological conditions in karst area，the relationship among the recharge，runoff and discharge of the karst groundwater within the project area of the deep-buried diversion tunnel for Jiajiang Water Control Project in Guizhou Province is studied through the analysis of the karst hydrogeological data combined with the factors of the stratumstructure，lithological combination，topographical feature，etc. therein by taking establishing the hydrogeological conceptual model and the tunnel water inrush predicting method for karst area as the target. On the basis of this，the responses from the water inrushes on rainfall events under different circumstances are analyzed and studied in accordance with the in situ investigation of the typical adits with water inrush of the tunnel，and then the water inrush modes of the tunnel in karst area are summarized. For the characteristics of different water inrush modes，the corresponding calculation methods and treatment measures for the water inrush are proposed herein. The result shows that the water inrush modes of the tunnel in karst area can be divided into the water control mode of karst channel，the water control mode of bedding plane and the joint water control mode of both fault zone and subsurface stream. The response from the water inrush in the No. 4 adit of Maochang Tunnel with the water control mode of karst channel to rainfall is rapid，thus the water rush is suitable to be calculated with water-balance method; the water inrush in the No. 2 adit of Shuidaqiao Tunnel with the water control mode of bedding plane is greatly influenced by the anisotropic permeability of rock mass，thus the water inrush is suitable to be predicted by the method of the finite element seepage analysis for the anisotropic permeability of rock mass; while the water inrush in the No. 4 adit of Shuidaqiao Tunnel with the the joint water control mode of both fault zone and subsurface stream mainly inflows from subsurface stream through fault zone，thus the water inrush can be calculated and analyzed with the method of 3 － d finite element simulation of seepage field. The errors from the predictions made on the water inrushes of the typical adits with the methods mentioned above are 6. 97% ，4. 81% and 1. 13% respectively. The study result has a certain referential significance for the construction of deep-buried tunnel in karst area.