A shear strength criterion of rock joints under dynamic normal load

The shear strength of rock joints under dynamic normal load (DNL) conditions is quite different from that under constant normal loading (CNL) conditions. However, existing studies seldom involve the shear strength prediction of rock joints under DNL conditions. Therefore, a series of shear tests for rock joints under DNL conditions were carried out. The evolutions of the shear strength parameters, including both cohesion and internal friction angle, with dynamic loading amplitude and frequency were investigated according to the experimental results. A shear strength criterion for rock joints under DNL conditions was developed. The proposed model was verified by comparing the theoretically predicted values with experimental results, both of which showed excellent agreement. Additionally, the strength criterion is utilized to predict the peak shear strength under CNL and new DNL conditions. These prediction results were further validated by experimental methods, which extend the applicability of the proposed strength criterion. This study can provide valuable references for the stability evaluation of rock formation engineering and geological hazard warning under dynamic load disturbance.