Influence of weathering processes on the shear strength of siltstones from a flysch rock mass along the northern Adriatic coast of Croatia

  • Martina Vivoda Prodan
  • Marta Mileusnić
  • Snježana Mihalić Arbanas
  • Željko ArbanasEmail author
Original Paper


Weathering processes cause significant changes in the engineering properties of rocks. Slope instability in flysch rock formations along the northern Adriatic coast of Croatia is related to the effects of weathering on the shear strength of siltstones from the flysch rock mass. Therefore, changes in geotechnical properties according to weathering grade are of immense importance in relation to instability processes. In this work, we investigated siltstones from flysch rock masses in the study area, and evaluated changes in engineering properties due to weathering. The research began with field observations and determination of the strength of different weathering grades of siltstones in the area. Mineralogical and laboratory studies were subsequently conducted, and mineral content was determined for siltstones of different weathering grades. We also performed a series of drying–wetting cycles to simulate natural conditions of the weathering process involved in the disintegration of the rock material into sand-sized and smaller particles. This weathering process resulted in disintegration of the siltstone rock mass into smaller particles that were not a unique rock block, with the soil-like material consisting of unbound particles of rock. Laboratory tests were also carried out on the soil-like material to determine the specific gravity, grain size distribution, Atterberg limits and residual shear strength for the different weathering grades of siltstones. Based on this research, we determined the changes in engineering properties for different weathering grades. Our results underscore the significant influence of the weathering process on mineral content, cation exchange capacity, liquid limit and residual shear strength, thus affecting slope stability in siltstones in flysch rock masses.


Siltstones Flysch rock mass Weathering Mineralogy Shear strength 



This work is supported in part by the University of Rijeka under project no. 475, entitled "Development of Landslide Monitoring and Early Warning System for the Purpose of Landslide Hazard Reduction." Equipment used in the study was obtained with financial support from the SATREPS [Science and Technology Research Partnership for Sustainable Development] program, financed by the Japan Science and Technology Agency and Japan International Cooperation Agency through the Project Risk Identification and Land-Use Planning for Disaster Mitigation of Landslides and Floods in Croatia. This support is gratefully acknowledged.


  1. Aljinović D, Jurak V, Mileusnić M, Slovenec D, Presečki F (2010) The origin and composition of flysch deposits as an attribute to the excessive erosion of the Slani Potok valley (“Salty Creek”). Geol Croat 63(3):313–322Google Scholar
  2. Arbanas Ž, Benac Č, Jurak V (2006) Causes of debris flow formation in flysch area of North Istria, Croatia. In: E De Lorenzini G, Brebbia CA (eds), Monitoring, simulation, prevention and remediation of dense and debris flows. WIT transaction on ecology and the environment, 283–292Google Scholar
  3. Arbanas Ž, Grošić M, Dugonjić S (2008) Behaviour of the reinforced cuts in flysch rock mass. In: Ellis Gm E, Hai-Sui Y, A. D, Thom N (Eds.), Proc. of 1. int. conf. on transportation geotechnics. Taylor and Francis Group, Nottigham, 283–291Google Scholar
  4. Arbanas Ž, Mihalić Arbanas S, Dugonjić Jovančević S, Vivoda M (2010) Brus landslide, translational block sliding in flysch rock mass. In: Zhao J, Labiouse V, Dudt JP, Mathier JF (eds) Proceedings of the European rock mechanics symposium (Eurock 2010). Laussane, 635–638Google Scholar
  5. Arbanas Ž, Dugonjić S, Benac Č (2013) Causes of small scale landslides in Flysch deposits of Istria, Croatia. In: Margottini C, Canuti P, Sassa K (eds) Landslide science and practice, volume I: landslide inventory and susceptibility and hazard zoning. Springer, Berlin, pp 221–226CrossRefGoogle Scholar
  6. Arbanas Ž, Mihalić Arbanas S, Vivoda M, Peranić J, Dugonjić Jovančević S, Jagodnik V (2014) Identification, monitoring and simulation of landslides in the Rječina River Valley, Croatia. In: Proceedings of SATREP workshop on landslides. Hanoi, 200–213Google Scholar
  7. Arel E, Tuǧrul A (2001) Weathering and its relation to geomechanical properties of Cavusbasi granitic rocks in northwestern Turkey. Bull Eng Geol Environ 60:123–133CrossRefGoogle Scholar
  8. ASTM (2004) Standard test method for slake durability of shales and similar weak rocks (D4644-87). American Society for testing and Materials, PhiladelphiaGoogle Scholar
  9. Aydin A (2015) ISRM suggested method for determination of the Schmidt hammer rebound hardness: revised version. In: Ulusay R (ed) The ISRM suggested methods for rock characterization, testing and monitoring: 2007-2014 SE-2. Springer, Berlin, 25–33. doi:  10.1007/978-3-319-07713-0_2
  10. Benac Č, Arbanas Ž, Jurak V, Oštrić M, Ožanić N (2005) Complex landslide in the Rječina valley (Croatia): origin and sliding mechanism. Bull Eng Geol Environ 64(4):361–371CrossRefGoogle Scholar
  11. Benac Č, Dugonjić S, Arbanas Ž, Oštrić M, Jurak V (2009) The origin of instability phenomena along the karst-flysch contacts. In: I. Vrkljan (ed) ISRM international symposium rock engineering in difficult ground conditions: soft rock and karst. CRC Press, Boca Raton, 757–761Google Scholar
  12. Benac Č, Mihalić S, Vivoda M (2010) Geological and geomorphological conditions in the area of Rječina river and Dubračina river catchments (Primorsko-Goranska County, Croatia). In: Abstracts book of 1st Japanese–Croatian project workshop “International experience”. Dubrovnik, p 39Google Scholar
  13. Benac Č, Dugonjić S, Vivoda M, Oštrić M, Arbanas Ž (2011) A complex landslide in the Rječina Valley: results of monitoring 1998–2010. Geol Croat 64(3):239–249. doi: 10.4154/GC.2011.20 Google Scholar
  14. Benac Č, Oštrić M, Dugonjić Jovančević S (2014) Geotehnical properties in relation to grain-size and mineral composition: the Grohovo landslide case study (Croatia). Geol Croat 67(2):127–136CrossRefGoogle Scholar
  15. Bergant S, Tišljar J, Šparica M (2003) Eocen carbonates and flysch deposits of the Pazin basin. In: 22nd IAS meeting of sedimentology. Field trip guidebook. OpatijaGoogle Scholar
  16. Bernat S, Domlija P, Mihalić Arbanas S (2014) Slope movements and erosion phenomena in the Dubračina river basin: A geomorphological approach. In: Proceedings of 1st regional symposium on landslides in the adriatic-balkan region “Landslide and flood hazard assessment”, 79–84Google Scholar
  17. Bhattarai P, Marui H, Tiwari B, Watanabe N, Tuladhar G, Aoyama K (2006) Influence of weathering on physical and mechanical properties of mudstone. Disaster Mitigation of Debris Flows, Slope Failures and Landslides, Niigata, pp 467–479Google Scholar
  18. Blašković I (1999) Tectonics of part of the Vinodol Valley within the model of the continental crust subduction. Geol Croat 52(2):153–189Google Scholar
  19. Brown ET (1981) Rock characterization, testing & monitoring: ISRM suggested methods. Commission on testing methods, international society for rock mechanics. Pergamon Press, OxfordGoogle Scholar
  20. Cano M, Tomás R (2015) An approach for characterising the weathering behaviour of Flysch slopes applied to the carbonatic Flysch of Alicante (Spain). Bull Eng Geol Environ 74(2):443–463. doi: 10.1007/s10064-014-0632-6 CrossRefGoogle Scholar
  21. Cano M, Tomás R (2016) Proposal of a new parameter for the weathering characterization of carbonate flysch-like rock masses: the potential degradation index (PDI). Rock Mech Rock Eng. doi: 10.1007/s00603-016-0915-2 Google Scholar
  22. Cardoso R, Alonso EE (2009) Degradation of compacted marls: a microstructural investigation. Soils Found 49(3):315–327. doi: 10.3208/sandf.49.315 CrossRefGoogle Scholar
  23. Ceryan S, Tudes S, Ceryan N (2008) Influence of weathering on the engineering properties of Harsit granitic rocks (NE Turkey). Bull Eng Geol Environ 67:97–104CrossRefGoogle Scholar
  24. Chandler RJ (1969) The effects of weathering on the shear strength properties of Keuper marl. Geotehnique 19(3):321–334CrossRefGoogle Scholar
  25. Chigira M, Oyama T (2000) Mechanism and effect of chemical weathering of sedimentary rocks. Eng Geol 55(1–2):3–14. doi: 10.1016/S0013-7952(99)00102-7 CrossRefGoogle Scholar
  26. Dick JC, Shakoor A (1995) Characterizing durability of mudrocks for slope stability purposes. Geol Soc Am Rev Eng Geol 10:121–130CrossRefGoogle Scholar
  27. Dugonjić Jovančević S, Arbanas Ž (2012) Recent landslides on the Istrian Peninsula, Croatia. Nat Hazards 62(3):1323–1338CrossRefGoogle Scholar
  28. Eberhardt E, Thuro K, Luginbuehl M (2005) Slope instability mechanisms in dipping interbedded conglomerates and weathered marls—the 1999 Rufi landslide, Switzerland. Eng Geol 77(1–2):35–56. doi: 10.1016/j.enggeo.2004.08.004 CrossRefGoogle Scholar
  29. Ehlen J (2002) Some effects of weathering on joints in granitic rocks. Catena 49(1–2):91–109. doi: 10.1016/S0341-8162(02)00019-X CrossRefGoogle Scholar
  30. El Amrani Paaza N, Lamas F, Irigaray C, Chacón J, Oteo C (2000) The residual shear strength of Neogene marly soils in the Granada and Guadix basins, southeastern Spain. Bull Eng Geol Environ 58(2):99–105. doi: 10.1007/s100640050003 CrossRefGoogle Scholar
  31. Erguler ZA, Shakoor A (2009) Quantification of fragment size distribution of clay-bearing rocks after slake durability testing. Environ Eng Geosci 15:81–89CrossRefGoogle Scholar
  32. Fookes PG, Gourley CS, Ohikere C (1988) Rock weathering in engineering time. Q J Eng Geol 21:33–57CrossRefGoogle Scholar
  33. Franklin JA, Chandra R (1972) The slake-durability test. Int J Rock Mech Min Sci Geomech Abstr 9:325–341. doi: 10.1016/0148-9062(72)90001-0 CrossRefGoogle Scholar
  34. Frydman S, Talesnick M, Geffen S, Shvarzman A (2007) Landslides and residual strength in marl profiles in Israel. Eng Geol 89(1–2):36–46CrossRefGoogle Scholar
  35. Gamble JC (1971) Durability-plasticity classification of shales and other argillaceous rocks. Ph.D Thesis. University of IllinoisGoogle Scholar
  36. Gulam V (2012) The erosion of flysch badlands in the Central Istria. Dissertation, University of Zagreb (in Croatian) Google Scholar
  37. Irfan TY, Dearman WR (1978) The engineering petrography of a weathered granite in Cornwall, England. Q J Eng Geol Hydrogeol 11:233–244. doi: 10.1144/GSL.QJEG.1978.011.03.03 CrossRefGoogle Scholar
  38. ISRM, Commission on Standardization of Laboratory and Field Test (1977) Suggested methods for determining water content, porosity, density, absorption and related properties and swelling and slake durability index properties. In: Ulusay R, Hudson JA (eds) The complete ISRM suggested methods for rock characterization, testing and monitoring:1974–2006Google Scholar
  39. Jurak, V. (1980) Personal notes (Unpublished material)Google Scholar
  40. Jurak V, Slovenec D, Mileusnić M (2005) Excessive flysch erosion—Slani Potok. Excursion guide book of the 3rd Croatian geological congress. Opatija, Croatia, pp 51–55Google Scholar
  41. Lee SG, Freitas MH (1988) Quantitative definition of highly weathered granite using the slake durability test. Geotehnique 38(4):635–640CrossRefGoogle Scholar
  42. Little AL (1969) The engineering classification of residual tropical soils. In: Proceedings of 7th international conference on soil mechanics and foundation engineering, Mexico, 1–10Google Scholar
  43. Marinčić S (1981) Eocene flysch of adriatic zone. Geol Vjesn 34:27–38 (In Croatian) Google Scholar
  44. Marinos P, Hoek E (2001) Estimating the geotechnical properties of heterogeneous rock masses such as flysch. Bull Eng Geol Environ 60(2):85–92. doi: 10.1007/s100640000090 CrossRefGoogle Scholar
  45. Martinez-Bofill J, Corominas J, Soler A (2004) Behaviour of the weak rock cut slopes and their characterization using the results of the slake durability test. Eng Geol Infrastruct Plan Eur 104:405–413. doi: 10.1007/978-3-540-39918-6_47 CrossRefGoogle Scholar
  46. Mihljević D, Prelogović E (1992) Structural-geomorphological characteristic of the mountain ranges Učka & Ćićarija. In: Bognar A (ed) Proceedings of the international symposium geomorphology and sea and the meeting of the geomorphological commission of the Carpatho-Balkan countries. Mali Lošinj, 13–24Google Scholar
  47. Miller RP (1965) Engineering classification and index properties for intact rock. Dissertation, University of IllinoisGoogle Scholar
  48. Miščević P, Vlastelica G (2011) Durability characterization of Marls from the region of Dalmatia, Croatia. Geotech Geol Eng 29(5):771–781. doi: 10.1007/s10706-011-9416-y CrossRefGoogle Scholar
  49. Miščević P, Števanić D, Štambuk-Cvitanović N (2009) Slope instability mechanisms in dipping conglomerates over weathered marls: Bol landslide, Croatia. Environ Geol 56:1417–1426CrossRefGoogle Scholar
  50. Oštrić M, Sassa K, Ljutić K, Vivoda M, He B, Takara K (2014) Manual of transportable ring shear apparatus, ICL-1. In: Proceedings of 1st regional symposium on landslides in the Adriatic-Balkan region “Landslide and flood hazard assessment”, Zagreb, 1–4Google Scholar
  51. Rahardjo H, Aung K, Leong E, Rezaur R (2004) Characteristics of residual soils in Singapore as formed by weathering. Eng Geol 73(1–2):157–169. doi: 10.1016/j.enggeo.2004.01.002 CrossRefGoogle Scholar
  52. Reiβmüller M (1997) Geotechnische Eigenschaften verwitterter Kfssener Mergel. Diploma Thesis, Technical University of Munich, MunichGoogle Scholar
  53. Sassa K, Fukuoka H, Wang G, Ishikawa N (2004) Undrained dynamic-loading ring-shear apparatus and its application to landslide dynamics. Landslides 1(1):7–19. doi: 10.1007/s10346-003-0004-y CrossRefGoogle Scholar
  54. Selby MJ (1993) Hillslope materials and processes. Oxford University Press, OxfordGoogle Scholar
  55. Tišljar J (2004) Sedimentology of clastic and siliciclastic sediments. Croatian geological survey, CroatiaGoogle Scholar
  56. Tsiambaos G (1991) Correlation of mineralogy and index properties with residual strength of Iraklion marls. Eng Geol 30:357–369CrossRefGoogle Scholar
  57. Turkington AV, Paradise TR (2005) Sandstone weathering: a century of research and innovation. Geomorphology 67(1–2):229–253. doi: 10.1016/j.geomorph.2004.09.028 CrossRefGoogle Scholar
  58. Ündül O, Tuǧrul A (2012) The influence of weathering on the engineering properties of Dunites. Rock Mech Rock Eng 45:225–239. doi: 10.1007/s00603-011-0174-1 CrossRefGoogle Scholar
  59. Utili, S. (2004) Evolution of natural slopes subject to weathering: an analytical and numerical study. Dissertation, Politecnico di MilanoGoogle Scholar
  60. Velić I, Vlahović I (2009) Geologic map of Republic of Croatia 1:300.000. Croatian geological survey, Zagreb (in Croatian) Google Scholar
  61. Vithana SB, Nakamura S, Gibo S, Yoshinaga A, Kimura S (2012) Correlation of large displacement drained shear strength of landslide soils measured by direct shear and ring shear devices. Landslides 9(3):305–314CrossRefGoogle Scholar
  62. Vivoda M, Benac Č, Žic E, Đomlija P, Dugonjić Jovančević S (2012) Geohazards in the Rječina valley in the past and present. Croat Waters J Water Econ 20(81):105–116 (in Croatian) Google Scholar
  63. Zhao J, Broms BB, Zhou Y, Choa V (1994) A study of the weathering of the bukit timah granite part A: review, field observations and geophysical survey. Bull Eng Geol Environ 49(1):97–106Google Scholar
  64. Žufić, E. (2011) Investigation of geotehnical properties of flysch rock mass in Istria area. MS Thesis, University of Zagreb (in Croatian) Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • Martina Vivoda Prodan
    • 1
  • Marta Mileusnić
    • 2
  • Snježana Mihalić Arbanas
    • 2
  • Željko Arbanas
    • 1
    Email author
  1. 1.Faculty of Civil EngineeringUniversity of RijekaRijekaCroatia
  2. 2.Faculty of Mining, Geology and Petroleum EngineeringUniversity of ZagrebZagrebCroatia

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