隧道开挖过程涌水量的动态模拟

Dynamic Simulation of Water Inflows During Tunnel Excavation

文章利用MATLAB软件对地下水流模拟程序MODFLOW进行了二次开发,将施工过程中不断掘进的隧道视为动态变化的边界条件,从而实现了理想条件下的隧道涌水量的动态模拟。将3种渗透系数场导入模型计算,结果表明:渗透系数场的非均质性对模拟有较大影响,在隧道揭露导水带时会发生涌水事件,之后总涌水量将经历衰减,直至下一次涌水事件发生;隧道某确定位置的最大涌水量发生在隧道开挖初时,随着隧道继续开挖该点的涌水量呈现负指函数衰减,衰减规律和初始流量相关,也与模拟区的渗透系数场分布有关。该研究为隧道施工过程涌水量预测提供了一定的理论参考,但还需根据实际的地层岩性、构造条件、工程施工进度等来改进模型,以期实现针对隧道工程实例的实时预报。

A secondary development of the groundwater flow simulation program MODFLOW was conducted with MATLAB software in this paper, which regards the continuously driven tunnel as a dynamic boundary condition, achieving a dynamic simulation of tunnel water inflows under ideal conditions. Three kinds of permeability coefficient fields were used as input for the model, and the calculation results show that： 1）the anisotropy of the permeability coefficient field has a great impact on simulation results; 2）a water inflow event will occur when a water-bearing zone in the tunnel is exposed, and the total water inflows will then gradually decrease until the next water inflow; and 3） the maximum water inflow occurs at the beginning of tunnel excavation in a defined location, then the water inflow at this location decreases in a negative exponential function with the attenuation law being related to the initial water flow and distribution of the permeability coefficient field of the simulated area. This study provides a theoretical reference for the prediction of water inflow during tunnel construction, while the model still needs to be improved according to actual formation lithology, structural conditions and construction progress in order to realize the real-time prediction of tunnel water inflow.