Constitutive model of soft rock disturbance creep based on disturbance factor

The surrounding rock around soft rock roadway in deep mine with dynamic disturbance has the characteris-tics of large rheological deformation and rapid deformation rate,which may lead to difficulty in supporting and frequent disasters. In order to study the characteristics and constitutive model of the soft rock creep damage with dynamic dis-turbance,using self-developed rock disturbance creep experimental system,a multi-stage loading creep experiment of the mud shale is carried out under dynamic disturbance. The experimental results show that the rheological deformation of the rock unsteady rheological curve is significantly different before and after the disturbance. When the stress level is relatively small,its strains happen to change suddenly after disturbance at the first and the second creep stage,then gradually take a very small rebound,eventually the rock deformation tends to a stable value. When the stress level is relatively high,the repetitious disturbance to the rock at the first and the second creep stage leads to the acceleration stage of rheological rate when the accumulation of energy in rocks reaches to the destroy energy. At the third creep stage under dynamic disturbance,the rock creep rate is accelerated and the time of rock failure is shortened. Based on the disturbance theory,the disturbance power and disturbance frequency as independent variables,a disturbance factor function is derived. Combining with the NRC model,a disturbance rheological constitutive model is proposed and the model parameters are identified. The results show that the theoretical curves are in good agreement with the experimen-tal curve,which verifies the model is able to describe the soft rock creep characteristics with dynamic disturbance. The result has a reference value for the study of stability of deep underground engineering project.