The effect of engineering geology on the rock load and squeezing potential in Lot2 of Imamzadeh-Hashem tunnel

Iranian Journal of Earth Sciences

مقاله 6، دوره 12، شماره 2، تیر 2020، صفحه 151-165   

نوع مقاله: Original Research Paper

شناسه دیجیتال (DOI): 10.30495/ijes.2020.673336

نویسندگان

Mohammad-Reza Baghban Golpasand^{* 1}؛ Seyyed-Ghafour Alavi²؛ Amirhassan Rezaei³

¹Department of Civil Engineering, Seraj Institute of Higher Education, Tabriz, Iran

²Departments of Earth Sciences, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran

³Faculty of Engineering, Azarbaijan Shahid Madani University, Tabriz, Iran

چکیده

The load entering from the ground surrounding on the tunnel’s lining is one of the effective parameters in the designation of a tunnel. The amount of this parameter, which is called Rock load in a rocky environment, depends on several factors such as the overburden thickness, geological and geomechanical conditions and the depth of tunnel. In the present study, the amount of rock load for the Lot 2 of Imamzadeh Hashem Tunnel (L2IHT) has been evaluated using various methods and the effect of geological characteristics of the rock units on the tunnel route has been investigated. For this purpose, different methods for estimating the rock load were introduced firstly, and then the amount of this parameter for the tunnel was estimated using these methods. To evaluate the thickness of the plastic zone around the tunnel, the numerical method, finite difference code of FLAC3D software, has been used. Comparison of the results obtained from different methods and their analysis indicates that the rock load applying from H-4 and H-10 rock units is more than the other units. This happens because of the specific geological characteristics of these rock units such as high degree of crushing due to the geological factors and being in the faulted zone. Therefore, it is required for the stronger lining of the tunnel in the range of these units.

کلیدواژه‌ها

Rock load؛ Squeezing؛ Engineering Geology؛ FLAC 3D؛ Lot 2 of Imamzadeh-Hashem Tunnel

مراجع

1. Anon (1995) The description and classification of weathered rocks for engineering purposes. Working Party Report. Qurterly Journal of Engineering Geology and Hydrogeology 28 (3), 207-242
2. Baghban Golpasand MR, DO N-A, DIAS D and Nikudel MR (2018) Effect of the lateral earth pressure coefficient on settlements during mechanized tunneling. Geomechanics and Engineers, 16 (6), 643-654.
3. Barton N, Lien R, Lunde J (1974) Engineering Classification of Rock Masses for the Design of Tunnel Support. Rock Mechanics 6, 189-236.
4. Bhasin R, Grimstad E (1996) The Use of Stress-Strength Relationships in the Assessment of Tunnel Stability. Tunnelling and Underground Space Technology 11 (1), 93-98.
5. Bieniawski ZT (1989) Engineering Rock Mass Classifications. John Wiley, Rotterdam, 189 p
6. Carranza-Torres C, Fairhurst C (2000) Application of the convergence-confinement method of tunnel design to rock-masses that satisfy the Hoek-Brown failure criterion. Tunnelling and Underground Space Technology152, 187–213.
7. Deere DU, Peck RB, Monsees JE, Parker HW, Schmidt B (1970) Design of tunnel support system. In: 49th Annual Meeting of the Highway Research Board, Washington, DC, 26-33.
8. EM 1110-2-2901 (1997) Engineering and Design: TUNNELS AND SHAFTS IN ROCK. U.S.Army, p. 236.
9. Goel RK, Jethwa JL (1991) Prediction of Support Pressure using RMR Classification. In: Proceeding of Indian Geotechnical Conference, Surat, India, 203-205.
10. Goel RK, Jethwa JL, Paithankar AG (1995a) Indian Experiences with Q and RMR System. Tunnelling and Underground Space Technology 10 (1), 97–109.
11. Goel RK, Jethwa JL, Paithakan AG (1995b) Tunnelling through the young Himalayas, a case history of the Maneri-Uttarkashi power tunnel. Engineering Geology 39, 31–44.
12. Goodman RE (1989) Introduction to Rock Mechanics. Wiley, Chichester, 2nd edn., 562 p.
13. Hassanpour J, Baghban Golpasand, MR, Hashemnezhad A (2014a) TBM performance prediction using new experimental model in Emamzadeh-Hashem tunnel, lot 2. In: Proceeding 5th Iranian Rock Mechanic Conference, Tarbiat Modares University, Tehran (In Persian)
14. Hasanpour R, Rostami J, Unver B (2014b) 3D finite difference model for simulation of double shield TBM tunneling in squeezing grounds. Tunnelling and Underground Space Technology 40, 109–126.
15. Hoek E, Brown ET (1997) Practical Estimates of Rock Mass Strength. international Journal of Rock Mechanic and Mining Sciennce 34 (8), 1165-1186.
16. Hoek E, Marinos P (2000) Predicting tunnel squeezing problems in weak heterogeneous rock masses. Tunnels and Tunnelling International pp. 15-21: part two.
17. ISRM (International Society for Rock Mechanics) (1978) commission on standardization of laboratory and field tests: Suggested methods for the quantitative description of discontinuities in rock masses. International Journal of Rock Mechanics and Mining Sciences 15(6), 319-368.
18. Itasca (2006) FLAC3D (Fast Lagrangian analysis of continua in 3D dimensions). User’s guide.
19. Jethwa JL, Singh B, Singh, Bhawani (1984) Estimation of ultimate rock pressure for tunnel linings under squeezing rock conditions-a new approach. In: Proceeding of the ISRM Symposium on Design and Performance of Underground Excavations, Cambridge, 231-238.
20. Palmstrom A (1982) The volumetric joint count- a useful and simple measure of the degree of rock jointing. In: Proceeding of 41st International Congress of International Association of Engineering Geology, Delphi, 5, 221-228.
21. Panthi KK (2006) Analysis of engineering geological uncertainties related to tunneling in Himalayan rock mass conditions. Doctoral Thesis, Norwegian University of Science and Technology, Trondheim, Norway
22. Ramoni M, Anagnostou G (2010) Thrust force requirements for TBMs in squeezing ground. Tunnelling and Underground Space Technology 25, 433–455.
23. Shaffiee Haghshenas S, Shaffiee Haghshenas S, Mikaeil R, Sirati Moghadam P, Shafiee Haghshenas A (2017) A New Model for Evaluating the Geological Risk Based on Geomechanical Properties —Case Study: The Second Part of Emamzade Hashem Tunnel. Electronic Journal of Geotechnical Engineering, 22 (01), 309-320.
24. Shamsoddin Saeed M, Maarefvand P (2014) Engineering Geological Study of NWCT Tunnel in Iran with Emphasis on Squeezing Problems. Indian Geotechnical Journal 44 (3), 357-396.
25. Singh B, Goel RK (1999) Rock Mass Classification - A Practical Approach in Civil Engineering. Elsevier Science Ltd., The Netherlands, 267.
26. Singh B, Jethwa JL, Dube AR, Singh B (1992) Correlation between observed support pressure and rock mass quality. Tunnelling and Underground Space Technology 7 1, 59– 74.
27. Terzaghi K (1946) Rock defects and loads on tunnel supports. In: Proceeding Rock tunneling with steel supports. Commercial Shearing and Stamping, Youngstown, p. 271.
28. Unal E (1983) Design Guidelines and Roof Control Standards for Coal Mine Roofs. Ph. D. Thesis, Pennsylvania State University, University Park, p. 355.
29. Zhao K, Janutolo M, Barla G (2012) A Completely 3D Model for the Simulation of Mechanized Tunnel Excavation. Rock Mechanics and Rock Engineering 45(4), 475-497.