Scientific paper ID 1965 : 2020/3

It has become a tradition in our country to assign the construction of road tunnels to engineering. In this way, the administration transfers all the risk to the contractor. For tunnels, this approach inevitably leads to huge difficulties for contractors and ultimately - to more expensive project implementation. The report clarifies the significant contradictions that arise systematically in the investment process in such cases. Ideas for solving them are proposed. The tunnels are built entirely in an underground environment and the study can never be exhaustive. Therefore, it is necessary for the different phases of design to gradually carry out maximum studies of the geological environment and to design the necessary optimal fortification structures and tunnel lining. The report argues that it is not justified for the contracting authority to transfer the huge risk to the contractor. It is noted that there are no norms for the scope of the geological survey for the tunnels, but there are other indirect indicators on which to prepare the terms of reference and to control the results. The degraded role of project consultants has been criticized. Modern high-tech solutions to the problem by solving optimization problems and artificial intelligence are presented. The findings confirm that engineering more often leads to more expensive projects. The results of the application of the rules of the Yellow and Red Books of FIDIC in our country in the construction of road and railway tunnels have been compared and a number of conclusions have been drawn. The approaches in compiling the tender conditions and the terms of reference for the construction of tunnels in our country are consistently analyzed and the vulnerabilities that carry high risk are shown. It is reported that the Yellow Book poses too high a risk for builders. The main points in the new Emerald Book of FIDIC, dedicated especially to underground construction, are quoted. The advantages of this book over the others are highlighted and the need for its rapid implementation in Bulgaria is emphasized.