Influence of weathering on the engineering properties of Harsit granitic rocks (NE Turkey)

Weathering and hydrothermal alteration of the granitic rocks in the Eastern Black Sea Region (NE Turkey) are important phenomena affecting the engineering projects in the region. The study investigated the probable paths of rock-forming mineral transformations due to weathering in the Harsit granitoid rocks, the changes of the major oxides as a consequence of weathering and the effects of weathering on the engineering properties. To identify the changes in the major oxides, the volume concentrations were considered in relation to the dry density. Chemical leaching during weathering was shown to be significant in changing the minerals. It was concluded that the engineering properties of the weathered granitic rocks can be most reliably predicted by P-wave velocity.RésuméLes altérations météoriques et hydrothermales de roches granitiques dans la région de la Mer Noire orientale (NE de la Turquie) jouent un rôle notable dans les projets d’ingénierie de cette région. L’étude a concerné les modes de transformations minèralogiques et l’évolution des principaux oxydes rèsultant de l’altération météorique des roches granitoïdes de Harsit, ainsi que les effets de ces transformations sur les propriétés géotechniques de ces roches. Pour suivre l’évolution des principaux oxydes, leurs concentrations volumiques ont été analysées en fonction de la densité sèche des matériaux. Le rôle de la lixiviation pendant l’altération a été souligné comme facteur important de l’évolution minéralogique. De plus, il a été montré que les propriétés géotechniques des roches granitiques altérées pouvaient être prédites de façon assez fiable par les vitesses de propagation des ondes P.

[1]  A. Parker.  An Index of Weathering for Silicate Rocks , 1970, Geological Magazine.

[2]  E. T. Brown.  Rock characterization, testing & monitoring: ISRM suggested methods , 1981 .

[3]  Zulfu Gurocak,et al.  Effect of weathering on the geomechanical properties of the Miocene basalts in Malatya, Eastern Turkey , 2005 .

[4]  G. E. Powell,et al.  Engineering geological investigations for pile foundations on a deeply weathered granitic rock in Hong Kong , 1985 .

[5]  S. G. Lee,et al.  Quantitative definition of highly weathered granite using the slake durability test , 1988 .

[6]  R. M. Göktan,et al.  A SUGGESTED IMPROVEMENT TO THE SCHMIDT REBOUND HARDNESS ISRM SUGGESTED METHOD WITH PARTICULAR REFERENCE TO ROCK MACHINEABILITY , 1993 .

[7]  J. Banfield,et al.  Chemical weathering of silicates in nature; a microscopic perspective with theoretical considerations , 1995 .

[8]  M. S. Braga,et al.  Weathering of the Oporto granite: geotechnical and physical properties , 2002 .

[9]  C. F. Lee,et al.  Engineering and geological characteristics of granite weathering profiles in South China , 2003 .

[10]  Anand S. Gupta,et al.  Weathering indices and their applicability for crystalline rocks , 2001 .

[11]  Atiye Tugrul,et al.  Weathering and its relation to geomechanical properties of Cavusbasi granitic rocks in northwestern Turkey , 2001 .

[12]  J. Banfield.  The mineralogy and chemistry of granite weathering , 1985 .

[13]  W. D. Keller.  The Nascence of Clay Minerals , 1985 .

[14]  M. Sorriso-Valvo,et al.  Weathering of gneiss in Calabria, Southern Italy , 2001 .

[15]  D. Boztuǧ,et al.  Comperative Geochemistry of Four Plutons From the Cretaceous-Palaeogene Central Eastern Anatolian Alkaline Province (Divriği Region, Sivas, Turkey) , 1997, Turkish Journal of Earth Sciences.

[16]  M. Selby,et al.  Hillslope materials and processes , 1982 .

[17]  Tamer Topal,et al.  Deterioration mechanisms of tuffs in Midas monument , 2003 .

[18]  P. Reiche.  A survey of weathering processes and products , 1950 .

[19]  S. Augustithis.  Leaching and diffusion in rocks and their weathering products , 1983 .

[20]  T. Topal,et al.  Effect of weathering on the geomechanical properties of andesite, Ankara – Turkey , 2006 .

[21]  Comprehensive study of the weathered condition of welded tuff from a historic stone bridge in Kagoshima, Japan , 2000 .

[22]  Atiye Tugrul,et al.  The Effect of Chemical Weathering on the Engineering Properties of Eocene Basalts in Northeastern Turkey , 1997 .

[23]  F. C. Loughnan,et al.  Chemical Weathering of the Silicate Minerals , 1970 .

[24]  J. A. Franklin,et al.  Suggested method for determining point load strength , 1985 .

[25]  R. Eggleton,et al.  Weathering of Basalt: Changes in Rock Chemistry and Mineralogy , 1987 .

[26]  N. Duzgoren-Aydin,et al.  Chemical Heterogeneities of Weathered IgneousProfiles: Implications for Chemical Indices , 2003 .

[27]  I. Kheoruenromne,et al.  Isovolumetric geochemical investigation of a buried granite saprolite near Columbia, SC, U.S.A. , 1978 .

[28]  N. Duzgoren-Aydin,et al.  Behaviour of chemical elements during weathering of pyroclastic rocks, Hong Kong. , 2001, Environment international.

[29]  N. Duzgoren-Aydin,et al.  Re-assessment of chemical weathering indices: case study on pyroclastic rocks of Hong Kong , 2002 .

[30]  T. Irfan,et al.  Mineralogy, fabric properties and classification of weathered granites in Hong Kong , 1996, Quarterly Journal of Engineering Geology.