ABSTRACT
The peak shear strength of joints can be directly determined by means of laboratory or in situ tests; alternatively the joint surface roughness (JRC)and JCS parameters can be obtained on the basis of experimental surveys and measurements which can be correlated with JRC and JCS. JRC determination free of scale effects can be determined by means of simple tilt, pull or push tests carried out on natural rock blocks having, as dimensions, the spacing of the cross joints. Different mathematical formulations for an objective JRC determination have been proposed by several authors. The methodology presented for an objective JRC determination utilizes geostatistical techniques and is herein based on the correlation of the surface irregularities for the distance variation. Geostatistics has already been introduced in Geomechanics for the spatial analysis of the fracture geometrical and physical characteristics and the construction of geomechanical models.
