Abstract
Active landslides in clay shales are widespread in Mediterranean countries. One of their characteristics is that the mobilized shear strength corresponds to the residual strength. The residual friction angle of clays depends on pore fluid composition which, in formations of marine origin, could have changed after emersion from the sea because of a number of processes, e.g., contact with rain or fresh water. This study aims at evaluating the influence of pore fluid composition and of its changes on the behaviour of Costa della Gaveta landslide, used as a case study. The natural pore fluid composition was analysed; then, the influence of such composition on the residual strength, and the effects of its variation on the shear creep behaviour were investigated. The paper shows that the natural pore fluid is a composite salt solution with variable concentration. It exhibits characteristics close to those of seawater at about 30 m depth, whereas it is very dilute close to the ground surface. Salt solutions at various concentrations and distilled water were thus used to simulate in the laboratory tests the effects of the different natural pore solutions. The results show that the residual friction angle varies significantly within the field concentration range. Moreover, exposure to distilled water causes a noticeable decrease in the residual strength during tests under constant shear displacement rate. Consistently, under constant driving shear stresses, time dependent displacements are observed, evolving with primary, secondary and tertiary creep phases, characterized, respectively, by decreasing, constant and increasing displacement rates.
Similar content being viewed by others
References
ASTM D422 - 63 (2007) Standard test method for particle-size analysis of soils. Book of Standards Vol 04.08
Augustesen A, Liingaard M, Lade PV (2004) Evaluation of time-dependent behavior of soils. Int J Geomech 4(3):137–156
Bjerrum L (1954) Geotechnical properties of Norwegian marine clays. Geotechnique 4(2):49–69
Bjerrum L (1955) Stability of natural slopes in quick clay. Geotechnique 5:1–101
Bjerrum L, Rosenqvist IT (1956) Some experiments with artificially sedimented clays. Geotechnique 6(4):124–136
BS 1377–2 (1990) Methods of test for soils for civil engineering purposes. Classification tests. Part 2, Ch 4.3 & 4.4
Cascini L, Calvello M, Grimaldi GM (2010) Groundwater modeling for the analysis of active slow-moving landslides. J Geotech Geoenviron Eng 136(9):1220–1230
Cascini L, Calvello M, Grimaldi GM (2014) Displacement trends of slow-moving landslides: classification and forecasting. J Mt Sci 11(3):592–606
Chapman DL (1913) A contribution to the theory of electrocapillarity. Philos Mag 25(6):475–481
Chen Z, Mi H, Zhang F, Wang X (2003) A simplified method for 3D slope stability analysis. Can Geotech J 40:675–683
Christian GD (1994) Analytical chemistry, 5th edn. Wiley, New York
Comegna L, Picarelli L, Urciuoli G (2007) The mechanics of mudslides as a cyclic undrained-drained process. Landslides 4(3):217–232
Corominas J, Moya J, Ledesma A, Lloret A, Gili JA (2005) Prediction of ground displacements and velocities from groundwater level changes at the Vallcebre landslide (Eastern Pyrenees, Spain). Landslides 2:83–96
Cruden DM, Varnes DJ (1996) Landslide types and processes. In: Turner AK, Schuster RL (eds) Landslides investigation and mitigation. Transportation research board, US National Research Council. Special Report 247, Washington, DC, Ch 3, pp. 36–75
D’Elia B (1975) Aspetti meccanici delle frane tipo “colata”. Ital Geotech J 1:32–42
Di Maio C (1996a) Exposure of bentonite to salt solution: osmotic and mechanical effects. Geotechnique 46(4):695–707
Di Maio C (1996b) The influence of pore fluid composition on the residual shear strength of some natural clayey soils. Proc Int Symp Landslides 2:1189–1194
Di Maio C (1998) Discussion on exposure of bentonite to salt solution: osmotic and mechanical effects. Geotechnique 48(3):433–436
Di Maio C (2004) Consolidation, swelling and swelling pressure induced by exposure of clay soils to fluids different from the pore fluid. Chemo-mechanical couplings in porous media Geomechanics and Biomechanics. Springer-Verlag, pp 19–43
Di Maio C, Fenelli GB (1994) Residual strength of kaolin and bentonite: the influence of their constitutive pore fluid. Geotechnique 44(4):217–226
Di Maio C, Santoli L, Schiavone P (2004) Volume change behaviour of clays: the influence of mineral composition, pore fluid composition and stress state. Mech Mater 36:435–451
Di Maio C, Vassallo R, Vallario M, Pascale S, Sdao F (2010) Structure and kinematics of a landslide in a complex clayey formation of the Italian Southern Apennines. Eng Geol 116:311–322
Di Maio C, Vassallo R, Vallario M (2013) Plastic and viscous shear displacements of a deep and very slow landslide in stiff clay formation. Eng Geol 162:53–66
Geertsema M, Torrance JK (2005) Quick clay from the Mink Creek landslide near Terrace, British Columbia: geotechnical properties, mineralogy, and geochemistry. Can Geotech J 42:907–918
Gouy G (1910) Charge électrique à la surface d’un electrolyte. J Phis (Paris) 4(9):456–468
Harbaugh AW (2005) MODFLOW-2005, The U.S. Geological Survey modular ground-water model - the Ground-Water Flow Process: U.S. Geological Survey Techniques and Methods
Hungr O, Leroueil S, Picarelli L (2014) The Varnes classification of landslide types, an update. Landslides 11(2):167–194
Iverson RM (1985) A constitutive equation for mass-movement behaviour. J Geol 93(2):143–160
Kenney TC (1967) The infuence of mineralogical composition on the residual strength of natural soils. Proc Oslo Conf on Shear Strength Properties of Natural Soils and Rocks 1:123–129. AAs & Whals Boktrykkeri, Oslo
Leroueil S (2001) Natural slopes and cuts: movement and failure mechanisms. Geotechnique 51(3):197–243
Mesri G, Olson RE (1970) Shear strength of montmorillonite. Geotechnique 20(3):261–270
Mitchell JK (1993) Fundamentals of soil behavior, 2nd edn. Wiley, New York
Moore R, Brunsden D (1996) Physico-chemical effects on the behaviour of a coastal mudslide. Geotechnique 46(2):259–278
Moum J, Rosenqvist IT (1961) The mechanical properties of montmorillonitica and illitic clays related to the electrolytes of the pore water. Proc 5th Int Conf on SMFE 1:263–267
Picarelli L, Di Maio C (2010) Deterioration processes of hard clays and clay shales. Geol Soc Lond Eng Geol Spec Publ 23:15–32. doi:10.1144/EGSP23.3
Picarelli L, Di Maio C, Olivares L, Urciuoli G (2000) Properties and behaviour of tectonized clay shales in Italy. Proc 2nd Int Symp on Hard soils and soft rocks, Naples, pp 1211–1242
Picarelli L, Urciouli G, Ramondini M, Comegna L (2005) Main features of mudslides in tectonised highly fissured clay shales. Landslides 2(1):15–30
Pilson MEQ (2013) An introduction to the chemistry of the sea, 2nd edn. Cambridge University Press, UK
Rosenqvist IT (1966) The Norwegian research into the properties of quick clay—a review. Eng Geol 1:445–450
Schulz WH, McKenna JP, Kibler JD, Biavati G (2009) Relations between hydrology and velocity of a continuously moving landslide—evidence of pore-pressure feedback regulating landslide motion? Landslides 6:181–190
Sridharan A (1991) Engineering behaviour of fine grained soils. Indian Geotech J 21(1):1–136
Sridharan A, Ventakappa Rao G (1973) Mechanisms controlling volume change of saturated clays and the role of the effective stress concept. Geotechnique 23(3):359–382
Suhaydu JN, Prior DB (1978) Explanation of submarine landslide morphology by stability analysis and rheological models. Offshore Technol Conf, Houston, pp 1075–1079
Summa V (2006) Final report of the project “Monitoraggio della Frana di Costa della Gaveta del Comune di Potenza” (Monitoring of Costa della Gaveta Landslide in Potenza), in Italian, CNR-IMAA (National Research Council of Italy), Tito (PZ), Italy
Tika TE, Vaughan PR, Lemos LT (1996) Fast shearing of pre-existing shear zones in soil. Geotechnique 46(2):197–233
Vassallo R, Di Maio C, Comegna L, Picarelli L (2012) Some considerations on the mechanics of a large earthslide in stiff clays. Proc 11th Int and 2nd N Am Symp on Landslides and Engineered Slopes, Banff, Canada, vol 1, pp 963–968
Vassallo R, Grimaldi GM, Di Maio C (2014) Pore water pressures induced by historical rain series in a clayey landslide: 3D modeling. Landslides. doi:10.1007/s11069-011-9984-4
Yen BC (1969) Stability of slopes undergoing creep deformation. J Soil Mech Found Div ASCE 95(4):1075–1096
Acknowledgments
The authors would like to thank Mr. M. Belvedere for carrying out in situ measurements. The authors are particularly grateful to Prof. S. Masi and Mr. D. Molfese who carried out chemical analyses on the salt solutions. Part of this research has been funded by the Italian Ministry of Education, University and Research (PRIN project 2010–2011: landslide risk mitigation through sustainable countermeasures). Special thanks to Prof. Luciano Picarelli for inviting us to give a lecture on this topic at MWL 2013.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Di Maio, C., Scaringi, G. & Vassallo, R. Residual strength and creep behaviour on the slip surface of specimens of a landslide in marine origin clay shales: influence of pore fluid composition. Landslides 12, 657–667 (2015). https://doi.org/10.1007/s10346-014-0511-z
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10346-014-0511-z