A. Fahimifar - Department of civil and environmental engineering, Amirkabir university of technology, Hafez Ave, Tehran, Iran
A.R. Hedayat - Department of civil and environmental engineering, Amirkabir university of technology, Hafez Ave, Tehran, Iran

A new rigorous approach for calculating the distribution of stresses and displacements around a circular opening excavated in a strain-softening generalized Hoek-Brown rock mass is presented. After the yield criterion, the plastic potential function, and the evolution of Hoek-Brown strength parameters are defined, the differential equilibrium equation and equation of compatibility of deformations are solved simultaneously by means of Runge-Kutta forth-order method. In addition, the applicability and accuracy of the proposed method is shown through an example. Finally, the influence of the softening parameter, appearing in the evolution of Hoek-Brown parameters, is examined through the establishment of the ground response curves.

Circular opening, elasto-plastic analysis, strain-softening, Hoek-Brown criterion.