Tunneling practice has been unsuccessfully led by non-engineering professions and as result if often associated with long construction delays and significant cost overruns. In this paper, a model is proposed that emphasizes the practical benefits of flexibility and cooperation in tunneling practice. The Tunneling Game Model (TGM) is a two-person cooperative game which is formulated as a bargaining situation. The two players, the owner and the contractor, have the opportunity to collaboratefor mutual benefit. Two utility functions are proposed to determine the psychological characteristics of the players. The construction of each utility function is based on sustainability, professional-technical agreements, and risk allocation in contract documents.
In the early days, tunneling was a traditional and local craft-based process. In fact, temporary timber support was adapted to particular conditions and lining in brickwork depended on local supply availability. But, only after the concept of ?if the ground is allowed to deform slightly, it can contribute to its own support? was understood, the timber support was replaced by steel support and tunneling became a ?technology-based-art? [1].Now, the effects of design-construction-support can be quantified. As a result, adapting the support to the expected behavior of the ground became the universal principle of good tunneling.
The reason is that owners with legal and financial backgrounds do not understand the criteria for successful tunneling projects, imposing over-rigid terms and allocation of risk in face of uncertainties:(1) political influences supporting particular objectives; (2) early estimation made by economic advisors with little understanding of technical issues; (3) responsibility fragmentation in the tunneling project elements; (4) unsatisfactory attention to climate risk (technical solutions dominated by contractual provisions); (5) opacity of contract documents and adversarial relationships;(6) inflexible schedules without adequate understanding of essential features; and (7)tendering processes based on the cheap approach, thus preventing favorable outcomes. In other words, engineering analysis and decisions are often in the hands of other professions, associating tunneling projects with uncontrollable costs and long construction delays.
