TITLE:
New Approach of Geomechanical Properties by Scale Effect and Fractal Analysis in the Kedougou-Kenieba Inlier (Senegal-West Africa)
AUTHORS:
Déthié Sarr, Meissa Fall, Papa Malick Ngom, Mamadou Gueye
KEYWORDS:
Rock; Scale Effect; Fractal; Kédougou; Sedimentary; Igneous
JOURNAL NAME:
Geomaterials,
Vol.3 No.4,
October
14,
2013
ABSTRACT: This paper shows geometric aspects of rock masses in the Senegalese
side of Kédougou-Kéniéba inlier. The studies are done in one part on
sedimentary rocks (represented by sandstones) with stratification and on the other part in igneous rocks (represented by basalts). Geometric studies are the
fractal configuration and the scale effect. Scale effect is stud- ied by
comparing the results of mechanical tests done in the laboratory and on
outcrops. For all samples, laboratory pa- rameters are higher than
values of field. In this paper, scale effect is characterized by the decrease of
mechanical pa- rameters from laboratory samples to field. The scale coefficient is
defined and characterizes the relation between me- chanical
properties. More importantly, the scale effect is more significant. This
scale effect depends largely on the rock anisotropy. The anisotropy depends on
the fracturation and the filling. The scale effect takes into account
the fracturation, the filling minerals and their diversity which define the
complexity of the rock. The anisotropy is complex; the impact of scale effect
traduced by an increase of scale coefficient is the highest.
Configuration of discontinuities also defines fractal geometry. This fractal
aspect appears on the asperities, the spacing and the apertures of discontinuities.
The fractal dimension is different from a parameter to another. All these two
parameters estimate the stage of fracturation of the rock in a geological
system and depend one on another if they are studied in the same element.