On the geology and the geotechnical properties of pyroclastic flow deposits of the Colli Albani

  • Manuela Cecconi
  • Maurizio Scarapazzi
  • Giulia M. B. Viggiani
Original Paper

Abstract

This paper presents the results of an experimental investigation into the engineering geology properties of three pyroclastic deposits from the Colli Albani volcanic complex, typical of the subsoil of Rome (Italy). In their natural state, these materials are coarse-grained weak rocks, generally unsaturated in situ. The mechanical properties of the material are related to the geological origin of the deposits, their formation environment and mechanisms. These are also revealed by peculiar micro-structural features. A technical sheet for the description and classification of these deposits is proposed in the paper. The experimental investigation consisted mainly of identification and classification tests, one-dimensional compression and direct shear tests on saturated and dry samples. Due to their nature, non standard techniques had to be developed for sample preparation and testing. The main findings on compressibility, shear strength and creep properties of the materials are presented in the paper. Special attention is given to the definition of the failure envelope at relatively low confining stress and to the assessment of the influence of saturation on shear strength parameters.

Keywords

Pyroclastic deposits Technical classification Physical properties Compressibility Shear strength 

Résumé

L’article présente les résultats de travaux expérimentaux relatifs aux propriétés géotechniques de trois dépôts pyroclastiques issus de la formation volcanique de Colli Albani, typique du sous-sol de Rome (Italie). A l’état naturel, ces matériaux sont des roches tendres à grain grossier, généralement non saturées in situ. Les propriétés mécaniques de ces matériaux doivent être mises en rapport avec l’origine géologique des dépôts, les contextes environnementaux et les processus de formation, ces derniers étant révélés par des caractéristiques micro-structurales particulières. Une fiche technique est proposée dans l’article pour la description et la classification de ce type de dépôt. Les travaux expérimentaux ont consisté principalement en des tests d’identification et de classification, des essais de compression simple et des essais de cisaillement direct sur des échantillons saturés ou secs. Du fait de la nature de ces matériaux, des techniques particulières ont dû être mises en œuvre pour la préparation des échantillons et les essais. Les principaux résultats relatifs à la compressibilité, la résistance au cisaillement et les caractéristiques de fluage de ces matériaux sont présentés dans l’article. Une attention particulière est donnée à la définition de la courbe de rupture sous relativement faible confinement et à l’évaluation de l’influence de la saturation sur les paramètres de résistance au cisaillement.

Mots clés

Dépôts pyroclastiques Classification technique Propriétés physiques Compressibilité Résistance au cisaillement 

References

  1. Alberti A, Dragone M, Manfredini M, Segre AG (1967) Carta Geologica d’Italia, Foglio 150 Roma, scala 1:100000, 2nd edn. Sev. Geolog. ItGoogle Scholar
  2. Barton NR, Choubey V (1977) The shear strength of rock joints in theory and practice. Rock Mech 10:1–54CrossRefGoogle Scholar
  3. Bernabini M, Esu F, Martinetti S, Ribacchi R (1966) On the stability of the pillars in an underground quarry worked through soft pyroclastic rocks. Proc I Congr Int Soc Rock Mech, LisboaGoogle Scholar
  4. Camponeschi B, De Casa G, Giglio G, Volponi E (1982) Studio geologico-tettonico delle tavolette Ardea e Torre S. Lorenzo. Foglio 158 della Carta d’Italia, pp 151–180Google Scholar
  5. CARG (1992) La geologia di Roma dal centro storico alla periferia. In: Funicello R, Praturlon A, Giordano G (eds) APAT. Memorie descrittive della carta geologica d’ItaliaGoogle Scholar
  6. Cattoni E (2003) Comportamento meccanico e proprietà idrauliche della Pozzolana Nera dell’area romana in condizioni di parziale saturazione. Ph.D. Thesis, Università di PerugiaGoogle Scholar
  7. Cattoni E, Cecconi M, Pane V (2007) Geotechnical properties of an unsaturated pyroclastic soil from Roma. Bull Eng Geol Environ 66:403–414CrossRefGoogle Scholar
  8. Cecconi M (1998) Sample preparation of a problematic pyroclastic rock. Proc IS Probl Soils Sendai 1:165–168Google Scholar
  9. Cecconi M (1999) Caratteristiche strutturali e proprietà meccaniche di una piroclastite: la Pozzolana Nera dell’area romana. Ph.D. Thesis, Università di Roma Tor VergataGoogle Scholar
  10. Cecconi M, Viggiani GMB (1998) Physical and structural properties of a pyroclastic soft rock. Proc II Int Symp Hard Soils/Soft Rocks Napoli 1:85–91Google Scholar
  11. Cecconi M, Viggiani GMB (2000) Stability of sub-vertical cuts in pyroclastic deposits. In: Geoeng 2000 international conference on geotechnical & geological engineering, Melbourne, Australia, on CD romGoogle Scholar
  12. Cecconi M, Viggiani GMB (2001) Structural features and mechanical behaviour of a pyroclastic weak rock. Int J Numer Anal Meth Geomech 25:1525–1557CrossRefGoogle Scholar
  13. Cecconi M, Viggiani GMB, De Simone A, Tamagnini C (2003) A coarse grained weak rock with crushable grains: the Pozzolana Nera from Roma, International Workshop on “Constitutive Modelling and Analysis of Boundary Value Problems in Geotechnical Engineering—3X4”, Napoli 22–24 Aprile 2003, Hevelius Edizioni, pp 157–216Google Scholar
  14. Cecconi M, Evangelista A, Nicotera MV, Pane V, Cattoni E, Scotto di Santolo A (2005) Wetting paths upon shearing: experimental evidence and comparative analysis of two volcanic soils in the area of Napoli and Roma. In: Trento A, Romero EJ, Cui YJ (eds) Int. symp. on advanced experimental unsaturated soil mechanics, BalkemaGoogle Scholar
  15. Croce A (1954) Sulla compressibilità delle pozzolane quali terreni di fondazione. GeotecnicaGoogle Scholar
  16. Croce A, Penta F, Esu F (1961) Engineering properties of volcanic soils. V ICSMFE, ParisGoogle Scholar
  17. De Rita D, Funiciello R, Rosa C (1988) Caratteristiche deposizionali della II colata piroclastica del tuscolano-Artemisio. Boll GNVGoogle Scholar
  18. De Rita D, Faccenna C, Funiciello R, Rosa C (1995) Stratigraphy and volcano-tectonics. In: Trigila (ed) The volcano of the Alban Hills, Tipografia SGS RomaGoogle Scholar
  19. De Rita D, Fabbri M, Giordano G, Rodani S (2000) Proposta di organizzazione della stratigrafia delle aree vulcaniche secondo i principi delle unità stratigrafiche a limiti inconformi e sua informatizzazione. Bollettino Della Società Geologica Italiana 119:749–760Google Scholar
  20. De Rita D, Giordano G, Esposito A, Fabbri M, Rodani S (2002) Large volume phreatomagmatic ignimbrites from Colli Albani Volcano (Middle pleistocene, Italy). J Volcanol Geoth Res 118:79–98Google Scholar
  21. Del Prete M, Guadagno FM, Hawkins AB (1998) Preliminary report on the landslides of 5 May 1998, Campania, southern Italy. Bull Eng Geol Env 57:113–129CrossRefGoogle Scholar
  22. Diano G (2005) Caratterizzazione geomeccanica di Unità eruttive del distretto vulcanico dei Colli Albani (Lazio Centrale). Ph.D. Thesis, Università di Roma La SapienzaGoogle Scholar
  23. Esposito L, Guadagno FM (1998) Some special geotechnical properties of pumice deposits. Bull Eng Geol Env 57:41–50CrossRefGoogle Scholar
  24. Evangelista A, Aversa S (1994) Experimental evidence of non-linear and creep behaviour of pyroclastic rocks. In: Udine, Cristescu, Gioda (eds) Viscoplastic behaviour of geomaterials, CISM Courses and Lectures, n. 350. Springer, pp 55–101Google Scholar
  25. Ferrara G, Laurenzi MA, Taylor HP Jr, Tonarini S, Turi B (1985) Oxygen and strontium isotope studies of K-rich volcanic rocks from the Alban Hills, Italy. Earth Planet Sci Lett 75:13–28CrossRefGoogle Scholar
  26. Fisher RV, Schmincke HU (1984) Pyroclastic rocks. Springer, BerlinGoogle Scholar
  27. Fornaseri M, Scherillo A, Ventriglia U (1963) La regione vulcanica dei Colli Albani. Consiglio Nazionale delle Ricerche, RomaGoogle Scholar
  28. Freda C, Gaeta M, Palladino DM, Trigila R (1997) The Villa Senni (Alban Hills, central Italy): the role of H2O and CO2 on the magma chamber evolution and on the eruptive scenario. J Volcanol Geotherm Res 78:103–120CrossRefGoogle Scholar
  29. Funiciello R, Giordano G, De Rita D (2003) The Albano Maar lake (Colli Albani Volcano, Italy): recent volcanic activity and evidence of pre-Roman Age catastrophic lahar events. J Volcanol Geoth Res 123:43–61CrossRefGoogle Scholar
  30. Gaeta M, Freda C, Christensen JN, Dallai L, Marra F, Karner DB, Scarlato P (2006) Time-dependent geochemistry of clinopyroxene from the Alban Hills (Central Italy): clues to the source and evolution of ultrapotassic magmas. Lithos 86:330–346CrossRefGoogle Scholar
  31. Gagliardi C (2002) Comportamento meccanico di un materiale granulare a grani frantumabili. Tesi di laurea. Università di Roma Tor VergataGoogle Scholar
  32. Gillespie MR, Styles MT (1999) Classification of igneous rocks. British Geological Survey Research Report RR 99–06. BGS Rock Classification Scheme, vol 1Google Scholar
  33. Giordano G, De Benedetti AA, Diana A, Diano G, Gaudioso F, Marasco F, Miceli M, Mollo S, Cas RAF, Funiciello R (2006) The Colli Albani mafic caldera (Roma, Italy): stratigraphy, structure and petrology. J Volcanol Geotherm Res Elsevier 155:49–80CrossRefGoogle Scholar
  34. Goodman RE (1989) Introduction to rock mechanics. Wiley, New YorkGoogle Scholar
  35. Hoek E (1968) Brittle failure of rock. In: Stagg KG, Zienkiewicz OC (eds) Rock mechanics in engineering practice. Wiley, London, pp 99–124Google Scholar
  36. Hoek E, Brown ET (1980) Empirical strength criterion for rock masses. J Geotech Eng Div ASCE 106(GT9):1013–1035Google Scholar
  37. Hoek E, Carranza-Torres C, Corkum B (2002) Hoek-Brown failure criterion. In: Proceedings of 5th North American rock mechanics symposium, Toronto, Canada, pp 267–273Google Scholar
  38. Houghton BF, Wilson CJN (1989) A vesicularity index for pyroclastic deposits. Bull Volcanol 51(6):451–462CrossRefGoogle Scholar
  39. Karner DB, Marra F, Renne PR (2001) The history of the Monti Sabatini and Alban Hills volcanoes: groundwork for assessing volcanic-tectonic hazards for Rome. J Volcanol Geotherm Res 107(1–3):185–215CrossRefGoogle Scholar
  40. Lee IK (1991) Mechanical behaviour of compacted decomposed granite soil. PhD. Thesis, 1991, City UniversityGoogle Scholar
  41. Lembo Fazio A, Ribacchi R (1990) Problemi di stabilità di scarpate e cavità sotterranee in rocce piroclastiche. Terzo ciclo di conferenza di meccanica e ingegneria delle rocce: “Le rocce tenere”, TorinoGoogle Scholar
  42. Mesri G, Godlewski PM (1977) Time and stress compressibility inter-relationship. J Geotech Eng Div ASCE 103(GT5):417–430Google Scholar
  43. Mesri G, Ullrich CR, Choi YK (1978) The rate of swelling of overconsolidated clays subjected to unloading. Géotechnique 28(3):281–307CrossRefGoogle Scholar
  44. Miura K, Maeda K, Furukawa M, Toki S (1997) physical characteristics of sands with different primary properties. Soil Found 38(4):159–172Google Scholar
  45. O’Rourke TD, Crespo E (1988) Geotechnical properties of cemented volcanic soil. J Geotech Eng 114(10):1126–1147CrossRefGoogle Scholar
  46. Pellegrino A (1967) Proprietà fisico meccaniche dei terreni vulcanici nel napoletano. VIII Convegno di Geotecnica, CagliariGoogle Scholar
  47. Powers MC (1953) A new roundness scale for sedimentary particles. J Sediment Petrol 23:117–119Google Scholar
  48. Salvador A (1987) Unconformity bounded stratigraphic units. Geol Soc Am Bull 98:232–237CrossRefGoogle Scholar
  49. Scandone R, Giacomelli L (1998) Vulcanologia. Principi fisici e metodi d’indagine. Liguori Editori, NapoliGoogle Scholar
  50. Serri G, Innocenti F, Manetti P, Tonarini S, Ferrara G (1991) Il magmatismo neogenico quaternario dellarea tosco-laziale-umbra: implicazioni sui modelli di evoluzione geodinamica dell’Appennino settentrionale. Studi Geolog Camerti Vol Spec 1:429–463Google Scholar
  51. Shepard FP (1963) Submarine geology. Harper & Row, EvanstonGoogle Scholar
  52. Taylor DW (1948) Fundamentals of soil mechanics. Wiley, New YorkGoogle Scholar
  53. Turi B, Taylor, HPJ, Ferrara G (1991) Comparisons of 18O/16O and 87Sr / 86Sr in volcanic rocks from the Pontine Islands, M.Ernici, and Campania with other areas in Italy. In: Taylor HP, O’Neil JR, Kaplan IR (eds) Stable isotope geochemistry: a tribute to Samuel Epstein. Geoch Soc Spec Paper, vol 3, pp 307–324Google Scholar
  54. Trigila R, Agosta E, Currado C, De Benedetti AA, Freda C, Gaeta M, Palladino DM, Rosa C (1995) Petrology. In: Trigila R (ed) The volcano of the Alban Hills. SGS, Rome, pp 95–165Google Scholar
  55. Vaughan PR (1988) Characterising the mechanical properties of in situ residual soils. In: Proceedings of 2nd international conference on geomechanics in tropical soils, Singapore, pp 469–487Google Scholar

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • Manuela Cecconi
    • 1
  • Maurizio Scarapazzi
    • 2
  • Giulia M. B. Viggiani
    • 3
  1. 1.Department of Civil and Environmental EngineeringUniversity of PerugiaPerugiaItaly
  2. 2.Geoplanning S.r.l.RomeItaly
  3. 3.Department of Civil EngineeringUniversity of Roma Tor VergataRomeItaly

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