## 5 Application Example  
### Songshuwan Tunnel  
The Engineering Department of Lanzhou Railway Bureau Group Co., Ltd., which is located in Lanzhou, China; the Dingxi Engineering Section, which is situated in Dingxi, China, and the Lanzhou Jiaotong University Design and Research Institute Co., Ltd., which located in Lanzhou of China, jointly arrived at the Songshuwan Tunnel on the Longhai Line in November 2019 for an on-site disease investigation. The tunnel is a single line, built in 1960, with a total length of 2224.3 m. The current situation of the disease is due to complex surface and underground hydrogeological conditions, abundant groundwater, and the influence of surface loess sinkholes, resulting in serious problems, such as tunnel leakage and mud pumping. The technology of an additional drainage tunnel-self-priming pump was adopted for treatment.  
The windows were opened outward in the large and small refuge recess in the continuous extension of the serious leakage disease section, and a connecting channel was constructed. Then, the connection channel was constructed, and the discharge tunnel was excavated along the longitudinal direction of the tunnel, 7 m away from the side wall of the tunnel. In the discharge tunnel, the flow ditch and the reservoir were set up, the submersible hole was constructed, and the pipe was buried to drain the groundwater in the surrounding rock within the side wall and the arch to the discharge tunnel. When the  
\begin{table}
\begin{tabular}{c c c c} \hline
**Treatment Measures** & **Superiority** & **Deficiencies** \\ \hline Grouting reinforcement technology & The construction technology is simple and has little influence on the line operation. & The operation risks and the costs are high, the construction period is long, and the water-plugging effect cannot be guaranteed. \\ \hline Inverted arch and bottom pavement replacement technology & Based on disease treatment, the bearing capacity of the foundation can be improved. & The cost is high, the construction time is long, and the overhead line is needed in the construction, which has a dramatic impact on the line operation. \\ \hline Deepened side ditch technology & Reduces the damage of groundwater to the surrounding rock of the tunnel basement. & The construction period is long, and the damage to the tunnel side wall structure is significant. The drainage hole is easy to block, resulting in the disease not being cured. \\ \hline Additional drainage tunnel–self-priming pump technology & Completely solves the problem of mud pumping. & High engineering cost \\ \hline \end{tabular}
\end{table}
Table 1: Comparison of advantages and disadvantages of four treatment schemes for mud pumping disease of tunnel foundation.  
\begin{table}
\begin{tabular}{c c c c c} \hline  & **Grouting Reinforcement Technology** & **Inverted Arch and Bottom Frequency Technology** & **Deepened Side Ditch Technology** & **Additional Drainage Tunnel–Self-Priming Pump Technology** \\ \hline Project cost & Moderate & Small (local circumstance) & High & Slightly higher \\ \hline The difficulty of construction & Elementary & Moderate & Difficult & Moderate \\ \hline Environmental impact degree & Influential & Moderate & Slight influence & Slight influence \\ \hline Disease treatment effect & Deviation and non-thoroughgoing & Local treatment effect is effective & Deviation and non-thoroughgoing & Completely effective in the section \\ \hline \end{tabular}
\end{table}
Table 2: Comparative analysis table of practicability of four treatment schemes.  
water level in the reservoir reaches a certain level, the self-priming pump automatically started to pump the water to the side ditch to drain away.