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Computers and Concrete Volume 20, Number 4, October 2017 , pages 429-437 DOI: https://doi.org/10.12989/cac.2017.20.4.429 |
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Investigation of ratio of TBM disc spacing to penetration depth in rocks with different tensile strengths using PFC2D |
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Vahab Sarfarazi, Hadi Haeri, Alireza Bagher Shemirani, Ahmadreza Hedayat and Seyed Shahin Hosseini
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| Abstract | ||
| In this study, the effect of the tensile strength and ratio of disc spacing to penetration depth on the efficiency of tunnel boring machine (TBM) is investigated using Particle flow code (PFC) in two dimensions. Models with dimensions of 150x70 mm made of rocks with four different tensile strength values of 5 MPa, 10 MPa, 15 MPa and 20 MPa were separately analyzed and two \"U\" shape cutters with width of 10 mm were penetrated into the rock model by velocity rate of 0.1 mm/s. The spacing between cutters was also varied in this study. Failure patterns for 5 different penetration depths of 3 mm, 4 mm, 5 mm, 6 mm, and 7 mm were registered. Totally 100 indentation test were performed to study the optimal tool-rock interaction. An equation relating mechanical rock properties with geometric characteristics for the optimal TBM performance is proposed. The results of numerical simulations show that the effective rock-cutting condition corresponding to the minimum specific energy can be estimated by an optimized disc spacing to penetration depth, which, in fact, is found to be proportional to the rock\'s tensile strength. | ||
| Key Words | ||
| TBM; PFC2D; disc spacing to penetration depth; rock tensile strength | ||
| Address | ||
| Vahab Sarfarazi: Department of Mining Engineering, Hamedan University of Technology, Hamedan, Iran Hadi Haeri: Young Researchers and Elite Club, Bafgh Branch, Islamic Azad University, Bafgh, Iran Alireza Bagher Shemirani: Department of Civil Engineering, Sadra Institute of Higher Education, Tehran, Iran Ahmadreza Hedayat: Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado 80401, USA Seyed Shahin Hosseini: Department of Civil Engineering, Aria University of Sciences and Sustainability, Tehran, Iran | ||