Numerical evaluation of rock strength with different sizes of circular opening

Abstract

Abstract The presence of opening in the rock may be natural or artificial. In such circumstances, the stability should be examined through studying the strength of the rock. In the present study, the effect of size of the circular opening on the compressive and flexural strengths of limestone rocks has been studied. Both, the compressive and flexural strengths under confining pressure have been examined numerically. Two types of 2D-rock models have been studied are (200×200 mm2) and (200×700 mm2), respectively, for compression and flexural states with three sizes of openings having diameters of 10, 25, and 40 mm. The results of compression state showed that the strength reduces with existing opening and the reduction increases with the size of opening. The unconfined rock exhibited higher reduction in the strength than that of confined one with exists of opening. In case of flexural state, both compressive and tensile strengths increase with the increasing confining pressure, while they decrease with the opening size. At higher confining pressure, the size of opening has insignificant effect on the tensile strength. The tensile strength of the unconfined rock remains unchanged with increase in the size of opening beyond certain limit.