Experimental And Constitutive Model Research On Deep Rock Relaxation Characteristics Under Dynamic Disturbances

Deep rock masses tend to be the complex stress environment of “three highs and one disturbance”.The deformation,strength and failure form of rock masses after dynamic disturbances such as earthquakes,blasting,and vehicle loads directly affect safety and stability in deep rock mass engineering construction.At the same time,most of the rock masses in engineering construction have significant rheological properties and have been in a fractured state for a long time.This state makes its epoch characteristics different from that of intact rocks.Therefore,it is of practical significance and academic to study the rheological characteristics of rock masses under the combination of high stress and external dynamic disturbance forces.It is of practical significance and academic to explain the underlying causes and internal mechanisms of some deep rock engineering disasters.It is of great significance to maintaining long-term stability of deep rock mass engineering and disaster prevention and control.In order to clarify the law and mechanism of the effect of dynamic disturbance on the rheological characteristics of rocks,this study first adopted a self-developed rock dynamic disturbance servo triaxial test system to perform stepwise stress relaxation tests under different confining pressure conditions on marble Investigate the changing rules of characteristic indicators and their influencing factors.Then,rock specimens under different confining pressure conditions are subjected to progressive loading stress relaxation-dynamic disturbance tests to explore the influence of the dynamic disturbance forces with fixed disturbance time and amplitude on the stress relaxation characteristics.At the same time,an orthogonal experiment was designed to study the effect of dynamic disturbance forces with different disturbance times and amplitudes on the stress relaxation of rock under uniaxial conditions.Finally,based on the above experimental data,a dynamic disturbance factor was proposed and added to the Burgers model.The main research work of the paper can be summarized as:(1)The gradual loading stress relaxation tests under different confining pressure conditions were carried out,and the stress relaxation characteristics and influencing factors of marble under different strain levels before and after the peak wereanalyzed.The variation of stress relaxation rate,stress relaxation rate and energy conversion characteristics during stress relaxation with confining pressure and strain level were analyzed;(2)The gradual loading stress relaxation-dynamic disturbance test under different confining pressure conditions was conducted to explore the stress-strain characteristics,stress relaxation characteristics,and dynamic disturbance process of marble under different confining pressure and different axial strain levels.Law of deformation amount and anisotropic failure characteristics(3)Uniaxial stepwise stress relaxation-dynamic disturbance tests with different dynamic disturbance frequencies and amplitudes were carried out.The stress-strain relationship,the variation of peak strength,and the variation of stress relaxation at different axial strain levels are analyzed.A stress relaxation-dynamic disturbance constitutive model for marble is proposed.