Schedule compression in tunneling projects by adjusting workflow variability

Abstract

Usually, the tunneling operation is on a critical path in road or railroad construction projects. For minimizing project duration, this study identifies feasible work scenarios, builds simulation models for each scenario, and then analyzes the average duration per unit length of driving distance and efficiency of tunneling equipment. The tunnel work face is usually advanced as far as the ground condition allows the intention to finish the work earlier. As the rock type changes, however, the length per cycle advances, and the work cycle time varies accordingly. Therefore, workflow variability occurs. Workflow variability in tunnel construction operations brings with it waiting time for each work crew and results in delays in the work process. This study evaluates the effects of workflow variability and suggests an approach for shortening the duration of tunneling work by adjusting the driving length of each excavation in the case of two parallel tunnels, not a single tunnel.