The TBM Model Based on Risk Evaluation

This Paper describes a study of the various risk factors on tunnel boring machine (TBM) and their differing impacts on cost and time. It has been concluded that it is important to make a clear distinction between normal cost and time, and the risk events that cause exceptional cost and time. The budget and tender price can be determined separately, both by the client and contractor respectively. To meet the demands placed on decision making for tender and procurement for currently favored construction-contracting methods, a new model for estimating tender price and budget has been developed, and is described in this paper. The predictions obtained from the estimation model are shown to be realistic, as the total construction cost and time obtained from the model correspond fairly well to the actual construction cost and time. The separate estimation of normal cost and time and exceptional cost and time contribute to the clarity of the results.