Application of Modified Tunnel Support System for Jointed Rock Mass along Himalayas
N. Abbas1,2, K. G. Li1, M. Z. Emad3, Nasir Abbas2
1Faculty of Land Resource Engineering, Kunming University of Science and Technology, Kunming, China
2Department of Mining Engineering Karakoram International University (KIU), Gilgit, Pakistan
3King Fahad University of Petroleum and Minerals-KFUPM Dhahran, Kingdom of Saudi Arabia
Keywords: Tunneling, rock mass rating, stress reduction factor, support
Abstract
Support design in underground mining and tunneling excavations is dependent on the geological and geotechnical behavior of rock mass. The rock mass rating (RMR) and Q-System are the key parameters to design support system. The existing support system in tunneling projects along Himalayas were studied, and it was observed that the support was lighter in some cases and heavier in others. Based on the real time data obtained from active tunneling projects and geologic conditions along Himalayas, the modified support criteria (RMR19) using back calculations and incorporating stress factor in RMR and Q have been applied in this study. The stress reduction factor of the Q-system was also studied. The existing and modified RMR and Q are statistically correlated with a significant R2 value.
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