Evaluation of the shear strength of rocks by cracks based on the results of testing samples with spherical indentors

Abstract

Experimental data on the relationship of the residual shear strength of rocks in closed cracks with the functional characteristics of intact rocks – the tensile and compressive components of adhesion, the roughness of the crack surfaces, and the level of normal stresses are presented. A unified integrated approach determines the shear strength of intact and destroyed rocks, the residual shear strength of closed rough cracks has been developed. The approach provides for the selection of stress intervals corresponding to different types of fracture, for each of which a strength criterion is proposed, expressed in terms of functional characteristics of intact rock. An express method for estimating the residual shear strength of rocks by cracks with a rough surface has been developed, in which an improved method of loading samples with spherical indentors is used as a basic test method. The express method implements the transition from the data of mechanical tests of samples with spherical indentors to the shear strength indicators for cracks in the rock mass, taking into account the level of normal stresses and the roughness of the crack surfaces measured in field conditions. In this case the roughness scale developed by Barton is used. The express method is informative and available in the fieldwork.

Scientific fundamentals for the use of serpentinized rocks from the eastern region of Cuba

“…In a general sense, the serpentine rocks of the Moa region have a high degree of serpentine, a phenomenon that is more accentuated in the Amores area than in Merceditas, but which does not limit its industrial application. Other regularities stand out in them, such as: the practically total absence of pyroxenes (less than 1%); the high content of forsterite (91 -94%); small contents of impurities such as iron that together favor its use as a refractory material [19].…”