ABSTRACT
In order to study the time-dependent deformation of surrounding rocks in underground caverns under the high stress, mechanical tests were carried out firstly to simulate the unloading stress path during the excavation process to obtain the unloading-fractured rocks, and then based on the triaxial creep tests on the unloading-fractured specimens, the time-dependent deformation behaviour of the unloading-fractured marble was studied. The axial, lateral and volumetric deformations all experienced the transient creep, steady creep and accelerated creep stages. The deformation was related to the deviatoric stress and the confining pressure, especially the confining pressure had a significant restraint effect on the lateral and volumetric deformation. The lateral creep deformation and steady creep rate both were greater than the axial creep deformation and steady creep rate, and the dilatancy of the unloading-fractured marble became stronger over time. The lateral deformation of the unloading-fractured marble has more significant time-dependent characteristics than the axial deformation, meaning that the lateral time-dependent deformation behaviour is the key to the stability of the surrounding rock in the underground cavern.
