Estimation of Tunnel Project Completion Time by Combining the CSM2020 Discrete Event Simulation Model with Decision Aid in Tunneling (DAT)

The decision-making process regarding the uncertainty in the project plan, alignment alternatives, and other project aspects can be accounted for using the Decision Aids in Tunneling (DAT) tool. One of the important input parameters in the DAT is the advance rate, and its accurate estimation can significantly improve the accuracy of the DAT. The advance rate comprises the estimation of the rate of penetration and machine utilization. A few models have been proposed to estimate utilization with different levels of accuracy. The CSM2020, which is a discrete event simulation-based model, has proven to offer a promising estimation of TBM utilization as it incorporates uncertainties in various tunneling activities. The model more reliably allows for the determination of the delays during the tunneling and hence more reliable machine utilization for a given machine type, geological settings, and operational conditions. In the present study, project data were analyzed, and utilization values were estimated using the CSM2020 model and used as input in the DAT to estimate overall anticipated machine performance in a given project. The results include the average completion time that was compared with the actual site data. The accuracy in the completion time shows that a combination of CSM2020 and DAT can be considered to be an effective approach to consider the uncertainties in the various tunnel operations, thereby offering a more accurate and reasonable estimation of completion time for mechanized tunnels. 1. INTRODUCTION AND BACKGROUND The modern world has given society marvelous underground structures and the comfort of traveling through railways, metros, and road tunnels. These underground spaces provide infrastructure that is difficult or impossible to construct above ground or whose presence above ground is unacceptable, undesirable or simply not feasible. They have the fundamental characteristics of protecting against almost all-natural threats (Goel et al., 2012). With the increasing world population, there is a necessity for sustainable development that does not compromise the future generations' correlations while meeting the present needs, and tunnels are considered a significant contributor to this. They have proven to be an efficient infrastructure in conveying freshwater, disposing of waste products, as a safe and fast conveyance route, functional during extreme weather conditions, and for bulk storage of liquids and gas.