基于复杂地质体精细刻画的隧洞涌水量动态预测方法

Dynamic prediction method of tunnel water inflow based on detailed depiction of complex geological bodies

  • 摘要: 在隧洞涌水量预测数值模拟中准确刻画倾斜断层、倾斜隧洞等不规则地质体和地下构筑物是一个难题,且预测时通常假定隧洞开挖瞬间完成,而未考虑施工进度。通过解决三维地质模型与三维地下水数值模型耦合过程中要求的非自相交性和密封性问题,提出一套基于复杂地质体精细刻画的隧洞涌水量动态预测方法。首先在三维地质建模软件中构造倾斜隧洞、竖井、倾斜断层和不规则地质体的密封性边界面,其中倾斜隧洞和竖井需根据开挖进度分段构建,进而建立三维地质体模型。随后将三维地质模型数据以ml文件格式导入三维地下水模拟软件Feflow,利用Feflow的完全非结构化网格功能实现对复杂地质体的精细剖分。最后在Feflow精细剖分复杂地质体的基础上,将隧洞边界设置为第三类边界,通过设置交换系数与参考水头,实现考虑隧洞开挖进度和施工工艺(如注浆、衬砌等)的隧洞涌水量动态预测。将本方法应用于某地下工程倾斜隧洞与竖井的涌水量计算,实际效果较好。

     

    Abstract: It is a challenge to accurately characterize the irregular geological bodies and underground structures such as inclined faults and inclined tunnels during the numerical simulation of tunnel water inflow prediction, and the prediction generally assumes that the tunnel excavation is completed instantaneously, without considering the construction progress. A dynamic prediction method for tunnel water inflow based on precise characterization of complex geometric bodies was proposed by addressing the non-self-intersection and watertight issues required in the coupling process of three-dimensional (3D) geological models and three-dimensional groundwater numerical models. Specifically, a sealed boundary interface of inclined tunnels, shafts, inclined faults and irregular geological bodies is firstly constructed in 3D geological modeling software. The inclined tunnels and shafts need to be segmented according to the excavation progress, and then a 3D geological model is established. Subsequently, the 3D geological model data is imported into the 3D groundwater simulation software Feflow in ml file format. Then the fully unstructured grid function of Feflow is used to achieve the fine gridding of the complex geometric bodies. Finally, the tunnel boundary is set as the third type boundary based on the detailed gridding of complex geometric body in Feflow. Thus, tunnel water inflow can be predicted dynamically by setting the exchange coefficients and reference water heads, with consideration to the tunnel excavation progress and construction techniques (such as grouting, lining, etc.). The method is applied to the calculation of water inflow of inclined tunnels and shafts in an underground project, with good practical effect.

     

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