Introducing uniform discrete event simulation (CSM2020) for modeling the TBM tunneling process

•Introduction of CSM2020 simulation model for utilization estimation.•Inclusion of tunneling activities & their interdependencies to estimate utilization.•Use of discrete event simulation (DES) for utilization estimation.•DES provide more accurate utilization estimation with flexibility of customization. Several models have been developed to predict utilization of Tunnel Boring Machines (TBMs) based on statistical analysis of available project databases. Apart from the existing models, use of discrete event simulation (DES) for estimation has also been examined for utilization prediction. The results of these models demonstrate strong sensitivity to the influence of geological conditions and site logistics and offer the ability to take the site specific conditions into account for estimation of machine utilization. The present study proposes the stochastic simulation model CSM2020 using Arena© software that encompasses all major tunneling activities that impact machine utilization. CSM2020 model offers more accurate estimation of machine utilization and higher flexibility to customize the estimates based on equipment, logistics, and ground conditions. Given the observed limitations in various commercial software packages including Arena©, and lack of access/experience with such software in the typical tunneling projects, a DES model was also developed by using MATLAB. The accuracy of both the CSM2020 and MATLAB DES models depends on the availability of data to incorporate the complex interdependencies of various subsystems and different tunneling activities. The utilizations estimated for selected projects using the two simulation models were within 1% of each other and the results were verified by comparing the estimated values with those from field observation. The MATLAB code did not require a license, and it offers a better opportunity to keep track of the activities in a database that can be subsequently used for data visualization and analyzed to evaluate utilization and availability of individual subsystems and resources.