## 5 Conclusions  
This study aimed to develop an operating model for application in a TBM simulator. First, four main operating parameters required for excavation were analyzed. Multiple regression analysis estimated the four parameter requirements depending on the ground conditions and the TBM's type and specifications. Further multiple regression analysis then determined the correlations between operational actions and mechanical responses. Detailed operation procedures and interlock and warning alarm systems were next designed for the operating model. Lastly, several simulations were tested for the operating model in the TBM simulator under the different conditions. The first multiple regression analysis confirmed that the estimated requirements for the main operating parameters varied with the ground conditions and TBM specifications. The required thrust and cutterhead torque were estimated to be greater for an EPB TBM than for a slurry TBM. The estimated thrust and cutterhead torque requirements increased with increasing TBM diameter, while the estimated rotation speed and advance rate requirements decreased. The estimated thrust and cutterhead torque requirements increased as the maximum thrust and cutterhead torque ratio increased. The four operating parameter requirements are expected to decrease as the maximum capacity of rotation speed increases. The next multiple regression analysis confirmed that it is possible to reliably estimate ten mechanical responses from the six operational actions (on which the three speed parameters have particular influence). The estimation of earth pressure needs only the most important key drivers for the management of TBM excavation, namely the shield jack and the screw conveyor rotation speeds. Further studies should focus on estimation of the cutterhead torque. Several simulations were tested for the operating model based on the determined interactions and the designed operation procedures (including interlock and warning alarm systems). The simulations confirmed that the operational actions properly adjusted the mechanical responses, and the warning alarm systems worked well independently following the mechanical responses. For estimating the four parameter requirements, less than 20 pieces of data were used. However, more data must be used to estimate the operating parameters reliably. The correlations of actions and responses were estimated based on the machine data obtained from the specific tunneling project with the ground condition comprising of sand and clay. However, the water level, cover depth, and ground properties enhanced by soil conditioning can be completely different depending on the projection conditions. Therefore, these variables should be considered for further regression analysis. This study estimated only ten mechanical responses based on six operational actions using multi regression analysis. Future studies could focus on creating other operating models, such as for lubrication, soil conditioning, and back-fill grouting works. The correlations of actions and responses were estimated based on ground conditions comprising sand and clay. If the field operating data for mixed ground or rock conditions were used for the multiple regression analysis, new correlations would be applied in the simulation. Ground surface settlement and mucking process were not considered in this study. As they are critical for TBM operation, both functions should also be considered in future studies. In addition, threshold values for the first warning were set to 80% of the maximum capacities regardless of mechanical responses. However, each threshold value would be set differently depending on the type of mechanical responses. Therefore, the threshold value in each mechanical response should be reset following the various TBM manuals or the reviews by TBM operators. Together with development of the operating model, the steering model for the TBM guidance with articulation and shield jack operations have been developed to help beginners in steering the TBM in curved excavations.