Weightage Effect during Back-Calculation of Rock-Mass Quality from the Installed Tunnel Support in Rock-Mass Rating and Tunneling Quality Index System
Source abstract
Abstract
In extensively used empirical rock-mass classification systems, the rock-mass rating (RMR) and tunneling quality index (Q) system, rock-mass quality, and tunnel span are used for the selection of rock bolt length and spacing and shotcrete thickness. In both systems, the rock bolt spacing and shotcrete thickness selection are based on the same principle, which is used for the back-calculation of the rock-mass quality. For back-calculation, there is no criterion for the selection of rock-bolt-spacing-based rock-mass quality weightage and shotcrete thickness along with tunnel-span-based rock-mass quality weightage. To determine this weightage effect during the back-calculation, five weightage cases are selected, explained through example, and applied using published data. In the RMR system, the weightage effect is expressed in terms of the difference between the calculated and back-calculated rock-mass quality in the two versions of RMR. In the Q system, the weightage effect is presented in plots of stress reduction factor versus relative block size. The results show that the weightage effect during back-calculation not only depends on the difference in rock-bolt-spacing-based rock-mass quality and shotcrete along with tunnel-span-based rock-mass quality, but also on their corresponding values.
Source: crossref · Quality: baseline
Research context
OpenAlex topics: Rock Mechanics and Modeling · Tunneling and Rock Mechanics · Geotechnical Engineering and Analysis
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
Department of Civil and Environmental Engineering, Hanyang University, ERICA Campus, Sangnok–gu, Ansan 15588, Korea
Department of Mining Engineering, Baluchistan University of Information Technology Engineering and Management Sciences (BUITEMS), Quetta 081, Pakistan
Department of Geological Engineering, Baluchistan University of Information Technology Engineering and Management Sciences (BUITEMS), Quetta 081, Pakistan
Funding
Ministry of Land, Infrastructure and Transport of the Korean government
References (31)
Show source-provided references
1. Numerical analysis and experimental study of hard roofs in fully mechanized mining faces under sleeve fracturing10.3390/min5040523 ↗
2. Deformation and mechanical characteristics of tunnel lining in tunnel intersection between subway station tunnel and construction tunnel10.1016/j.tust.2016.02.016 ↗
3. Geological and geomechanical heterogeneity in deep hydropower tunnels: A rock burst failure case study10.1016/j.tust.2018.11.009 ↗
4. Rehman, H., Ali, W., Naji, A., Kim, J.-J., Abdullah, R., and Yoo, H.-k. (2018). Review of rock-mass rating and tunneling quality index systems for tunnel design: Development, refinement, application and limitation. Appl. Sci., 8.10.3390/app8081250 ↗
5. Application of a small-timescale fatigue, crack-growth model to the plane stress/strain transition in predicting the lifetime of a tunnel-boring-machine cutter head10.1016/j.engfailanal.2016.11.002 ↗
6. The multi-stage rock fragmentation load prediction model of tunnel boring machine cutter group based on based on dense core theory10.1007/s00170-016-9375-9 ↗
7. Intense rockburst impacts in deep underground construction and their prevention10.1139/cgj-2014-0359 ↗
8. Ground behaviour and rock engineering tools for underground excavations10.1016/j.tust.2006.03.006 ↗
9. Ground behaviour and rock mass composition in underground excavations10.1016/j.tust.2006.11.005 ↗
10. Santos, V., da Silva, P.F., and Brito, M.G. (2018). Estimating rmr values for underground excavations in a rock mass. Minerals, 8.10.3390/min8030078 ↗
11. Engineering classification of jointed rock masses
12. Engineering classification of rock masses for the design of tunnel support10.1007/BF01239496 ↗
13. Rehman, H., Naji, A., Kim, J.-J., and Yoo, H.-K. (2018). Empirical evaluation of rock mass rating and tunneling quality index system for tunnel support design. Appl. Sci., 8.10.3390/app8050782 ↗
14. Use and misuse of rock mass classification systems with particular reference to the q-system10.1016/j.tust.2005.10.005 ↗
15. Analysis of structural interaction in tunnels using the covergence–confinement approach10.1016/S0886-7798(03)00004-X ↗
16. Extension of tunneling quality index and rock mass rating systems for tunnel support design through back calculations in highly stressed jointed rock mass: An empirical approach based on based on tunneling data from himalaya10.1016/j.tust.2018.11.050 ↗
17. Lee, J., Rehman, H., Naji, A., Kim, J.-J., and Yoo, H.-K. (2018). An empirical approach for tunnel support design through q and rmi systems in fractured rock mass. Appl. Sci., 8.10.3390/app8122659 ↗
18. Bieniawski, Z.T. (1989). Engineering Rock Mass Classifications: A Complete Manual for Engineers and Geologists in Mining, Civil, and Petroleum Engineering, John Wiley & Sons.
19. Celada, B., Tardáguila, I., Varona, P., Rodríguez, A., and Bieniawski, Z. (2014, January 9–15). Innovating Tunnel Design by an Improved Experience-Based RMR System. Proceedings of the World Tunnel Congress, Foz do Iguaçu, Brazil.
20. Bieniawski, Z. (1974, January 1–7). Geomechanics classification of rock masses and application in tunneling. Proceedings of the 3rd International Congress on Rock Mechanics, Denver, CO, USA.
21. Bieniawski, Z. (1975, January 21–25). Case studies: Prediction of rock mass behaviour by the geomechanics classification. Proceedings of the Second Australia-New Zealand Conference on Geomechanics, Brisbane, Australia.
22. Bieniawski, Z. (1979, January 2–8). The geomechanics classification in rock engineering applications. Proceedings of the 4th ISRM Congress, Montreux, Switzerland.
23. Bieniawski, Z. (2011, January 29). Misconceptions in the applications of rock mass classifications and their corrections. Proceedings of the ADIF Seminar on Advanced Geotechnical Characterization for Tunnel Design, Madrid, Spain.
24. Lowson, A., and Bieniawski, Z. (2013, January 23–26). Critical assessment of rmr based-based tunnel design practices: A practical engineer’s approach. Proceedings of the SME, Rapid Excavation and Tunnelling Conference, Washington, DC, USA.
25. Bieniawski, Z.T., Aguado, D., Celada, B., and Rodriquez, A. (2011). Forecasting tunnelling behaviour. T T Int., 39–42.
26. Some new q-value correlations to assist in site characterisation and tunnel design10.1016/S1365-1609(02)00011-4 ↗
27. NGI (2018, April 09). The q-System, Rock Mass Classification and Support Design. Available online: https://www.ngi.no/eng/Publications-and-library/Books/Q-system.
28. Src rock mass classification of tunnels under high tectonic stress excavated in weak rocks10.1016/S0013-7952(02)00286-7 ↗
29. Palmstrom, A. (1995). Rmi—A Rock Mass Characterization System for Rock Engineering Purposes, Oslo University.
30. Grimstad, E., and Barton, N. (1993, January 20–24). Updating the q-system for nmt. Proceedings of the International Symposium on Sprayed Concrete-Modern Use of Wet Mix Sprayed Concrete for Underground Support, Fagemes, Oslo, Norway.
31. Naji, A., Rehman, H., Emad, M., and Yoo, H. (2018). Impact of shear zone on rockburst in the deep neelum-jehlum hydropower tunnel: A numerical modeling approach. Energies, 11.10.20944/preprints201806.0195.v1 ↗