Schedule Risk Analysis for TBM Tunneling Based on Adaptive CYCLONE Simulation in a Geologic Uncertainty–Aware Context

Schedules are fundamental parameters for decision making in the design phase of tunnel construction projects. Schedule estimates of tunnel construction projects are subject to major uncertainties caused by uncertain geologic conditions and risks. This research presents an adaptive cyclic operation network simulation (CYCLONE) simulation technique to predict the schedule of tunnel boring machine (TBM) tunneling and quantifies the impacts of geologic risks along a tunnel in the design phase. A geologic prediction model is integrated with expert judgments to evaluate the probabilistic geologic risks along the tunnel alignment. An adaptive CYCLONE simulation technique is developed to flexibly adjust the durations, arrangements, and modes of construction operations in response to the occurrences of geologic risks and changes of geologic conditions. The applicability of the proposed method was demonstrated by an illustrative case study—Jinping (JP) hydraulic tunnel project in southwest China. The simulation results indicate that this project has a high risk of delays caused by geologic hazards. The analysis of the simulation results reveals that the schedules of tunneling and the uncertainty in the schedules will be underestimated if geologic risks are not considered well in the simulation. The incorporation of geologic risks and the adaptability of the simulation model would lead to a more accurate and robust simulation.