Dynamic reduction of time and cost uncertainties in tunneling projects

Abstract The cost and time estimation play a vital role in successfully completing a tunnel construction, however in most cases the estimation falls short compared to the actual time and cost that a tunnel construction consumes due to a number of geological and geotechnical reasons. This creates uncertainties in tunnel construction in terms time and cost. In this article, the effects of geological/geotechnical uncertainties in tunnel construction time and costs are being minimized through continuous updating techniques. The forecasting of geological conditions is based on continuous space-discrete state Markov process. Whereas, predicting the construction time and costs are based on Monte-Carlo (MC) simulation. To verify the tool applicability, it has been applied to Hamru tunnel in Iran. Also, to assess the updating effect on obtained outcomes during construction, the tool has been updated two times. In the first update, the total uncertainty in construction time and costs (measured by standard deviation) has been reduced by about 45% and 52%, respectively, followed by a reduction by about 66% and 61% in the second update. Finally, we can conclude that, the presented methodology is a helpful tool for tunnel project managers to identify risks and the possibility of deviations in their construction time and costs.