Practical assessment of grade in a weathered granite

  • Baynes F. J. 
  • Dearman W. R. 
  • Irfan T. Y. 


The variability of the engineering character of a chemically weathered granite from South-west England has been assessed in the context of quarrying to produce roadstone and concrete aggregates. Present grading schemes are reviewed with regard to their practical application, and have been developed into methods of grading capable of characterizing both the relevant engineering properties and the distribution of weathering grades in the weathering profile. The data obtained have been used to deduce a geological model for the prediction of rock conditions from an engineering geological plan of the quarry.

The economic implications of the distribution of weathering grades are considered from the aspects of practical quarrying grades related to the criteria of material quality and ease of excavation.


Rock Mass Rock Material British Standard Concrete Aggregate Weathered Granite 

Evaluation Pratique Du Degré D’Altération D’un Granite


La variabilité des propriétés techniques d’un granite du sud-ouest de l’Angleterre, chimiquement altéré, a été estimée dans le cadre de l’exploitation de carrières productrices de matériaux d’empierrement et de granulats pour le béton. On passe en revue les systèmes de séparation actuels, en ayant en vue leur application pratique, et on en tire des méthodes de séparation pouvant caractériser à la fois les propriétés techniques correspondantes et la répartition des degrés d’altération dans un profil d’altération. Les résultats obtenus furent utilisés pour en déduire un modèle géologique pour la prévision de la qualité des roches par l’examen d’un plan géotechnique de la carrière.

Les conséquences économiques de la répartition des degrès d’altération sont examinées au double point de vue de la facilité de l’excavation et de la détermination pratique d’un zonage de la carrière correspondant à la qualité du matériau.


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Copyright information

© International Assocaition of Engineering eology 1978

Authors and Affiliations

  • Baynes F. J. 
    • 1
  • Dearman W. R. 
    • 1
  • Irfan T. Y. 
    • 1
  1. 1.Engineering Geology Unit, Department of Geology, Drummond BuildingUniversity of Newcastle upon TyneU.K.

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