Investigating the effect of discontinuity geometrical parameters on the TBM performance in hard rock

摘要

By technological advancements, mechanization is also growing in engineering activities. A prominent example is the extensive use of tunnel boring machines (TBM) in the tunneling projects. The main motivations for using these machines are the lower cost and time saving, which are achieved with proper prediction of TBM performance. The prediction is influenced by various factors, such as intact rock parameters (compressive strength, tensile strength, brittleness), jointing parameters and geometrical parameters of the machine, including disc geometry and the spacing of discs from each other. In this paper, we study the TBM performance in real-scale, by simulation of cutterhead in real dimensions. Among the effective factors, the influence of orientation and spacing of joints on the performance of TBM in hard rock is investigated using numerical modeling. The results indicate that the 60' angle of the joints with the advance axis of TBM has the most effect on the TBM performance; and zero angle of the joints has the least effect. Also, regarding the spacing of joints, 400 mm spacing has been known as critical spacing. By increasing the spacing value above 400 mm, there is no changes in TBM performance. These results confirm previous studies conducted on this subject. Generally, based on the joint orientation, the ease of cutting in jointed rock mass increases about 30-70 percent.