## 4 Application of Operating Model to the Simulator
### Design of Interlock and Warning Systems
If the elective interlock associated with the shield jack pressure is turned on, only the warning system for that jack can be activated. Warning system includes two main stages: displaying a warning message and sounding an alarm. Threshold values are pre-set for each stage: first messages are displayed, then the alarm rings if the situation worsens. The warning system have two stages: _warning_ and _error_. Messages for both stages are displayed on-screen depending on the seriousness. The warning threshold is 20% less than the error threshold. For example, if the thrust reaches 80% of the maximum capacity (a pre-set value), a \"THRUST WARNING\" message is displayed. If the thrust then reaches 100%, a \"THRUST ERROR\" message replaces the warning message. The operator can resolve the warning issue as shown in Figure 6. If a warning signal is displayed, the operator should identify its cause and adjust the appropriate operational action. If there are not any solutions for the warning, operator should press the emergency button. If the operator can solve the problem, the operator should adjust the appropriate operational actions following the warning cause. However, if the problem cannot be solved and the situation worsens with an error signal display, the operator should press the emergency button to stop the entire excavation. If the operator does not press the button within a set time, the interlocked emergency shutdown system automatically suspends the entire operation. Figure 5: Example of mandatory interlock system associated with shield jack operation. Figure 6: Procedure for resolving a warning in the TBM simulator. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Part** & **Warning Title** & **Meaning** & **Set Value** & **Solution** \\ \hline \multirow{4}{*}{Shield jack} & Shield jack pressure & Extremely high shield jack pressure & 80\% & Decrease the shield jack speed \\ \cline{2-5}  & Thrust warning & Extremely high thrust & 80\% & Decrease the shield jack speed \\ \cline{2-5}  & Shield jack stroke limit & Reaching the maximum shield jack stroke. & 100\% & Stop the shield jack extension \\ \hline \multirow{4}{*}{Cutterhead} & Cutter torque warning & Extremely high torque & 80\% & Decrease the shield jack speed \\ \cline{2-5}  & Cutter rotation fault & Rotation speed showing poorer performance than expected & 80\% & Increase the amount of injection in front of the cutterhead. If ineffective, stop the rotation \\ \hline \multirow{2}{*}{Screw conveyor} & Screw conveyor pressure warning & Extremely high screw conveyor jack pressure & 80\% & Decrease the screw conveyor speed \\ \cline{2-5}  & Earth pressure warning & Extremely high (low) earth pressure for control & 80\% & Decrease the shield jack speed. \\ \hline \multirow{4}{*}{Cutter seal} & Inner cutter seal temperature warning & Extremely high inner cutter seal temperature & 100\% & Stop the cutterhead rotation \\ \cline{2-5}  & Outer cutter seal temperature warning & Extremely high outer cutter seal temperature & 100\% & Stop the cutterhead rotation \\ \hline \multirow{2}{*}{Water tank} & Cooling water temperature warning & Extremely high cooling water temperature & 100\% & Stop the cutterhead rotation \\ \hline \multirow{2}{*}{Oil tank} & Oil tank temperature warning & Extremely high oil tank temperature & 100\% & Stop the cutterhead rotation \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Summary of warning systems and countermeasures in the TBM simulator.