Abstract: At present, there is no unified standard for tunnel boring machine(TBM) type selection, resulting in great contrary arguments and influence on project. In this paper, the advantages and disadvantages of various types of TBMs and major points in dispute are summarized, and the concept of cost determination method is proposed for the first time. Then, the influence of various TBM type selection schemes on the major cost factors such as purchase cost, auxiliary equipment cost, space expense, supporting cost, labor cost, advancing speed, final tunnel quality, environmental protection cost, working environment, labor intensity, construction risks, safety risks, etc. is discussed to quantify the costs and further simplify the TBM type selection in comparison between cost of quantified and various types of TBMs and construction period. Based on this, a suit of quantitative and scientific methods for TBM tyoe selection is obtained. The cost determination method can be quantified at the economic level to improve the comparability with high operability, which is conducive to scientific type selection of TBM and the effective controlling of the costs and risks of project construction.

Key words: hard rock tunnel, tunnel boring machine type selection, cost quantification, cost determination method