Arbanas, Ž, Grošić, M & Briški, G 2008, 'Behaviour of Engineered Slopes in Flysch Rock Mass', in Y Potvin, J Carter, A Dyskin & R Jeffrey (eds), SHIRMS 2008: Proceedings of the First Southern Hemisphere International Rock Mechanics Symposium
, Australian Centre for Geomechanics, Perth, pp. 493-503, https://doi.org/10.36487/ACG_repo/808_07
This paper presents some experiences during the reinforced cut construction in the flysch slopes for the Adriatic motorway near the city of Rijeka, Croatia. The Cretaceous and the Paleogene limestone are situated on the top of the slope, while the Paleogene flysch crops are on the lower slope and in the bottom of the Draga Valley where the motorway is located. Unlike limestone rocks at the top of the slope, flysch rock mass is almost covered by colluvial deposits, residual soils and talus breccia. The major part of the motorway was constructed by cutting of the slopes in flysch rock mass. Stability of the slopes was ensured by the reinforcement of the rock mass with rockbolts and appropriate supporting system. The self boring rockbolts, in combination of multi-layered sprayed concrete or reinforced grid construction, were used. The deep boring drains were installed for dissipation of ground water collected at contact of permeable cover and impermeable flysch rock mass. The interactive rock mass cutting design, based on the observational methods, was introduced during the construction. The initial design of slopes construction was based on the recommended Hoek–Brown criteria for heterogeneous rock mass such as flysch. Design properties of the flysch rock mass were adopted on the geological strength index (GSI) concept. During the phase of interactive design the appropriate measured equipment was installed. This active design approach has allowed the designer, based on the rock mass conditions and monitoring results, to change the support system in the slopes at some unfavourable locations. The measured values and the back analysis enabled the establishment of real rock mass strength parameters and deformability modulus.
Arbanas, Ž., Benac, Č., Andrić, M. and Jardas, B. (1994) Geotechnical Properties of Flysch on The Adriatic Motorway from Orehovica to St. Kuzam, Proceedings Symposium Geotechnical Engineering in Transportation Projects, Croatian Geotechnical Society, Novigrad, October 5-8, pp. 181–190 (in Croatian).
Arbanas, Ž. (2002) The influence of rockbolts on the rock mass behaviour during excavation of deep cuts, MSc Thesis, Faculty of Civil Engineering, University of Zagreb (in Croatian), 207 p.
Arbanas, Ž. (2003) Construction of open pit Zagrad in Rijeka, Građevinar, Vol. 55, No. 10, pp. 591–597 (in Croatian).
Arbanas, Ž. (2004) Prediction of supported rock mass behaviour by analysing results of monitoring of constructed structures, PhD Thesis, Faculty of Civil Engineering, University of Zagreb (in Croatian), 220 p.
Arbanas, Ž., Kovačević, M.-S. and Szavits-Nossan, V. (2006a) Interactive design for deep excavations, Proceedings XIII Danube-European Conference on Geotechnical Engineering, Active Geotechnical Design in Infrastructure Development, J. Logar, A. Gaberc and B. Majes (editors), Slovenian Geotechnical Society, Ljubljana, May 29–31, Vol. 2, pp. 411–416.
Arbanas, Ž., Grošić, M. and Jurić-Kaćunić, D. (2006b) Influence of grouting and grouting mass properties on reinforced rock mass behaviour, Proceedings 4th Conference of the Croatian Geotechnical Society, Soil and Rock Improvement, Opatija, V. Szavits-Nossan and M.S. Kovačević (editors), Croatian Geotech. Society, Zagreb, 5–7 October, pp. 55–64.
Arbanas, Ž., Grošić, M. and Jurić-Kaćunić, D. (2007a) Experiences on flysch rock mass reinforcing in engineered slopes, The Second Half Century of Rock Mechanics, Proceedings 11th Congress of the Int. Society for Rock Mechanics, Lisbon, Portugal, July 9-13, Taylor and Francis Group, London, pp. 597-600.
Arbanas, Ž., Grošić, M. and Kovačević, M.-S. (2007b) Rock mass reinforcement systems in open pit excavations in urban areas, Slope Stability 2007, Proceedings 2007 Int. Symp. on Rock Slope Stability in Open Mining and Civil Engineering, Perth, Australia, September 12–14, Y. Potvin (editor), Australian Centre for Geomechanics, Perth, pp. 171–185.
GEO-Slope Int. Ltd (1998) User’s Guide Slope/W for Slope Stability Analysis, Version 4, Calgary.
Hoek, E. (1994) Strength of Rock and Rock Masses, ISRM News Journal, Vol. 2, (2), pp. 4–16.
Hoek, E. and Bray, J.W. (1977) Rock Slope Engineering, 2nd Edition, The Institute of Mining and Metallurgy, London, 527 p.
Hoek, E., Carranza-Torres, C.T. and Corkum, B. (2002) Hoek–Brown Failure Criterion, 2002 Edition, Proceedings 5th North American Rock Mechanics Symposium, Toronto, Canada, Dept. Civ. Engineering, University of Toronto, pp. 267–273.
Hoek, E., Kaiser, P.K. and Bawden, W.F. (1995) Support of Underground Excavations in Hard Rock, A.A. Balkema, Rotterdam, 215 p.
Hoek, E., Marinos, P. and Benissi, M. (1998) Applicability of the Geological Strength Index (GSI) Classification for Very Weak and Sheared Rock Masses. The Case of the Athens Shist Formation. Bull. Eng. Geol. Env., No. 57, pp. 151–160.
ISRM, Commission on Standardization of Laboratory and Field Test (1981a) Suggested Methods for the Rock Characterization, Testing and Monitoring, E.T. Brown (editor), Pergamon Press, Oxford, UK, 211p.
ISRM, Commission on Standardization of Laboratory and Field Test (1981b) Suggested Methods for the Quantitative Description of Discontinuities in Rock Masses, E.T. Brown (editor), Pergamon Press, Oxford, UK, 211p.
ISRM, Commission on Standardization of Laboratory and Field Test (1985) Suggested Methods for Determining Point Load Strength, Int. Jour. Rock Mech. Min. Sci. & Geomech. Abstr., Vol. 22, No. 2, pp. 51–60.
Kovačević, M.-S. (2003) The Observational Method and the Use of Geotechnical Measurements. Geotechnical problems with man–made and man influenced grounds, Proceedings 13th European. Conference on Soil Mechanics and Geotechnical Engineering, Prague, Czech Republic, August 25–28, Vol. 3, pp. 575–582.
Kovačević, M.-S. and Szavits-Nossan, V. (2006) Interactive design – Croatian experience, Proceeding of XIII Danube-European Conference on Geotechnical Engineering, Active Geotechnical Design in Infrastructure Development, J. Logar, A. Gaberc and B. Majes (editors), Slovenian Geotechnical Society, Ljubljana, May 29–31, Vol. 2, pp. 451–455.
Marinos, P. and Hoek, E. (2000) GSI: A geologically friendly tool for rock mass strength estimation, Proceedings GeoEng 2000 at the international conference on geotechnical and geological engineering, Melbourne, Technomic publishers, Lancaster, pp. 1422–1446.
Marinos, P. and Hoek, E. (2001) Estimating the Geotechnical Properties of Heterogeneous Rock Masses such as Flysch. Bull. Eng. Geol. Env., No. 60, pp. 85–92.
Marinos, V., Marinos, P. and Hoek, E. (2005) The geological strength index: applications and limitations, Bull. Eng. Geol. Environ, No. 64, pp. 55–65.
Nicholson, D.P., Tse, C.M. and Penny, C. (1999) The Observational Method in Ground Engineering: Principles and Applications, Report 185, CIRIA, London.
Peck, R.B. (1969) Advantages and limitations of the observational method in applied soil mechanics, Géotechnique, Vol. 19 (2), pp. 171–187.
Powderham, A.J. (1998) The observational method–application through progressive modification. Civil Engineering Practice, Journal of the Boston Society of Civil Engineers Section/ASCE, Vol. 13 (2), pp. 87–110.
Stillborg, B. (1994) Professional Users Handbook for Rock Bolting, Trans Tech Publications, Series on Rock and Soil Mechanics, Vol. 18, 2nd Edn., Clausthal-Zellerfeld, 164 p.
Szavits-Nossan, A. (2006) Observations on the observational Methods, Proceeding XIII Danube-European Conference on Geotechnical Engineering, Active Geotechnical Design in Infrastructure Development, J. Logar, A. Gaberc and B. Majes (editors), Slovenian Geotechnical Society, Ljubljana, May 29–31, Vol. 1, pp.171–178.
Terzaghi, K. and Peck, R.B. (1967) Soil Mechanics in Engineering Practice. John Wiley, New York.
Wyllie, D.C. and Mah, C.W. (2004) Rock Slope Engineering, Civil and Mining, 4th. Edn., Spon Press, New York, Taylor & Francis Group, 431 p.