Estimating Potential Cost Savings from Implementing an Innovative TBM Guidance Automation System

It is vitally important to evaluate costs, benefits and risks associated with adopting a new method or technology prior to field implementation. The present research proposes a framework for estimating potential cost savings by implementing new method or technology in the field in terms of: (1) productivity-dependent crew cost; (2) time-dependent indirect cost; and (3) time-independent indirect cost in the current practice that can be removed. In regards to system reliability, the proposed framework guides the identification of possible breakdown event categories and the evaluation of probabilities and consequences for each category of event. A case study is presented in the context of developing an innovative TBM guidance automation system in tunnel construction. Potential cost saving resulting from implementing the new automation system for a 1,000-meter-long drainage tunnel project in Edmonton, Alberta is estimated to be $346k, which far outweighs the additional cost associated with system reliability (about $ 34k) by about ten-fold.