Assessment of rock mechanical behavior considering stress dependent stiffness of the cracked domain within crack tensor-based approach

Abstract:

The analyses dedicated to media with prevalent discontinuities such as rocks has mostly been limited to inevitable simplifications to make engineering judgments on the material behavior feasible. Such assumptions, though favorable in numerical simulations, usually lead to overestimations in aseismic design of earthen structures. One of the forbidding tasks in modeling rock behavior is taking the stress dependency of stiffness into consideration which implies more complicated formulations. Although the theoretical relationship for such computations has already been proposed by scholars, there still remains some gaps in the real-world application of the aforementioned. The crack tensor-based formulation in describing stress-strain behavior of cracked rock is a case in point in which the fourth-rank crack tensor effect is usually ignored due to adopting equal normal and shear stiffnesses for the medium. Once the stiffnesses were distinguished in different values, the accompanying condition imposed by the formulation requires computation of fourth rank tensor which has not been obtained in a practical manner so far. In the present study, we aim to acquire the values via experimental measurements and implement the results to further improve the accuracy of the formulation used in characterizing mechanical behavior of rock samples.