# A Review of Deep Learning Applications in Tunneling and Underground Engineering in China
## 3 Intelligent Application of Deep Learning in Tunnel Engineering
### Subsea Tunnel
#### 3.3.3 Water Inrush Risk Prediction  
During the process of subsea tunnel construction, there is high pore water pressure around the tunnel, which will reduce the effective stress of the surrounding rock and make the arching ability much lower than that of other kinds of tunnels. In the case of unfavorable geological sections such as fault fracture zones, the magnitude of water pressure borne by the tunnel is enough to cause geological disasters like sudden water gushing so that the overlying water on the tunnel is connected and the tunnel is submerged [91], which poses a severe threat to construction safety. Water inrush and gushing accidents not only create technical obstacles to the opening of subsea tunnels but also seriously threaten the personal safety of mechanical facilities and construction personnel. The factors leading to water inrush in the subsea tunnel are shown in Figure 10. Countries all over the world often need to consider more factors in the process of designing and building subsea tunnels. Due to the lack of dynamic analysis of groundwater seepage after tunnel excavation, the theoretical analysis method, empirical analogy method, and numerical analysis method are mainly used to predict water inrush of the subsea tunnel in China [92; 93]. The former two methods can only roughly estimate the value, while the numerical analysis method is suitable for solving hydrogeological problems under complex conditions. However, the model establishment of this method generally needs to clarify hydrogeological conditions and obtain more parameters, which are usually difficult to meet in an underwater survey. If the calculation parameters are too few, the calculation results will be difficult to guarantee. Thus, this process of numerical analysis is difficult. The efficient algorithms and data analysis methods of deep learning can systematically and specifically analyze the key points and difficulties encountered in the process of sudden water disasters occurring in submarine tunnels while saving a lot of human and material resources. [PERSON] et al. [94] thought that the determination of the minimum overburden thickness was an important basis for the route planning of subsea tunnels, and there is a close relationship between overburden thickness and water inflow. The results of analytical and numerical analysis methods show that the relationship between water inflow and overburden thickness of subsea tunnels is approximately parabolic, and the relationship between minimum overburden thickness and seawater depth is approximately linear. [PERSON] et al. [95] also used this method to determine the factors the influencing water inrush and inflow of the tunnel. It is believed that the nature of the surrounding rock, the burial depth of the tunnel, and the angle of fault are related, but none of them can make a more accurate prediction result. The general empirical formula method is suitable for the subsea tunnel with a large permeability coefficient and sensitive hydraulic response. Once the surrounding environment of the tunnel changes, this method will also produce a large deviation. [PERSON] et al. [96] used the analytical method and numerical analysis method for the prediction of water inflow. On this basis, a GIS (geographic information system) is used as the basic platform by which to put the predicted results into the database of the evaluation system. Combined with the hydrogeological information during the construction process, the model parameters are continuously revised, and the final results are used as the basis for the evaluation of risk prediction problems. [PERSON] [97] summarized six influencing factors as the network input index of subsea tunnel water inflow according to previous work, combined it with a genetic algorithm to optimize the network, and finally achieved the prediction of water inflow work. The essence of sudden water disasters in submarine tunnels is the process of energy accumulation and the explosion of the underground aquifer and upper seawater pressure.