## 6 Conclusions  
In this study, a regional hydrogeological model was established by inverting the parameters of the natural flow field of a region. The model was then used to numerically simulate the distribution and variations in seepage fields that formed during the tunnel excavation under normal seepage conditions and limiting seepage conditions. The model was validated, and error analysis showed that the approach was suitable. The results for the two seepage conditions were compared to understand the range of the influence on the groundwater flow, and a formula was proposed to calculate the distance and degree to which groundwater was affected by the tunnel excavation. The main conclusions of this study are as follows. (1) The project is located in a mountainous area with complex topography, so it is impossible to analyze or assess the geology and hydrogeology of the whole study area. Here, from a field investigation, in situ tests, laboratory tests, and numerical simulations, an inverted model was established and verified, and simulations were produced to facilitate a study of how the tunnel excavation influenced groundwater in the area. This novel approach could be used for further studies of seepage fields in hydraulic tunnels. \begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**Maximum Inflow (m\({}^{3}\)/d)**} & **Fitting Formula of** & \multirow{2}{*}{**R\({}^{2}\)**} \\  & **Groundwater Influence Area** & \\ \hline
800 & \(\begin{array}{c}\text{h}=-1.618\times 10^{-6}x^{2}+\\ 0.00234x-0.798\end{array}\) & 0.9338 \\
1000 & \(\begin{array}{c}\text{h}=-2.313\times 10^{-6}x^{2}+\\ 0.00336x-1.141\end{array}\) & 0.9193 \\
2000 & \(\begin{array}{c}\text{h}=-1.228\times 10^{-6}x^{2}+\\ 0.00243x-1.060\end{array}\) & 0.9948 \\
4000 & \(\begin{array}{c}\text{h}=-2.653\times 10^{-6}x^{2}+\\ 0.00495x-2.157\end{array}\) & 0.9945 \\
5000 & \(\begin{array}{c}\text{h}=-3.305\times 10^{-6}x^{2}+\\ 0.00608x-2.643\end{array}\) & 0.9943 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Fitting formula of the range to which groundwater was influenced. (2) To understand the depletion of domestic wells and to determine what caused the seepage in the regional flow field, the changes in the water level at different well points were quantified. The results showed that after the tailwater tunnel was excavated, the groundwater levels in well points SJ96, SJ146, and SJ202 dropped to 0.054, 0.039, and 0.025 m, respectively. (3) The distance to which the tunnel construction affected the groundwater was then quantified. From these results, the variations in the groundwater flow field in the engineering area for different water inflow scenarios were simulated. The results showed that, for water inflows of 200, 400, 600, 800, and 1000 m\({}^{3}\)/d, the water level of SJ141 dropped by 0.861, 0.894, 0.927, 0.959, and 1.028 m, respectively, and the water level of well point SJ202 decreased by 0.025, 0.029, 0.031, 0.032, and 0.034 m, respectively. (4) The influence of limiting seepage conditions on the seepage field at different distances in the engineering area was then analyzed, and a formula was derived for calculating the distance to which groundwater was affected for a range of different water inflows. A'smart site' was established using the simulation outputs and real-time water level data from the three observation holes, ZK01, ZK02, and ZK03, to provide visual information and support the project management. (5) In following studies, data for the vibration effects of tunnel drilling and blasting will be combined with time-frequency domain analysis to obtain improved information about the degree and distance to which the tunnel excavation affects human settlements. Further studies will also contribute to achieving a goal of cleaner production, which will then help to realize the goal of peak carbon and carbon neutrality. Conceptualization, T.J.; Data curation, X.P. ; Funding acquisition, T.J.; Investigation, X.P., W.W., L.L., and S.G.; Methodology, T.J. and X.P. ; Project administration, T.J.; Software, X.P.