Experimental Study On Creep Performance Of Surrounding Rock In Deep Roadway Under Excavation Disturbance

With the deepening of the mine depth,the deep rocks are in the stress environment of three high and one disturbance.In the deep rock,the stress is close to the ultimate strength of the rock,showing obvious creep behavior.At the same time,when the deep mine is disturbed,failure may occur if no support is provided.In order to deeply explore the creep disturbance characteristics of surrounding rock,and to provide security and theoretical basis for the support of confining pressure,the creep disturbance experiment was carried out.1)The deformation of surrounding rock was studied by laboratory experiment.Made kind of rock specimen,analog simulation principle based on TAW-1000 D rock rheological experimental apparatus of disturbance to normal compression experiment of specimens,including the experiment of uniaxial compression and triaxial compression experiment,through the experiment found that with the increase of confining pressure,the bearing capacity of the specimen also will increase,and its deformation limit increases unceasingly,the modulus of elasticity also will increase.2)Uniaxial creep and triaxial creep tests were carried out on the specimens.Based on the TAW-1000 D rock rheological perturbation experiment instrument,the transitional creep method was adopted.It is found that: when the stress is lower than the long-term strength,the creep deformation of the specimen is smaller;when the stress is higher than the long-term strength,the creep deformation is more and more sensitive to the stress,and the resulting deformation is also increasing.At the same time,the specimen will be hardened,also accompanied by damage.Meanwhile,with the increase of confining pressure,the long-term strength and total strain of the specimens also increased.Under different confining pressures,the rock will also enter three stages(decay creep stage,constant creep stage and accelerated creep stage).With the increase of confining pressure,the time ratio of constant creep increases.It is also found that with the increase of surrounding rock,there may be secondary hardening of rock-like specimens,but the instantaneous deformation modulus of secondary hardening is lower than that of the first hardening.3)Uniaxial creep perturbation experiment and triaxial creep perturbation experiment were carried out on the specimen.Axial creep disturbance experiment,from the above analysis canfollow when rock is lower than long-term strength,disturbance of specimen has almost no effect,after the disturbance is close to or slightly higher than long-term strength,disturbance of specimen produce certain effect,but have little deformation when the preliminary static load is close to the ultimate strength of the rock,disturbance larger influence on specimen,can accelerate the destruction of the specimen.In the triaxial creep perturbation experiment,by changing the confining pressure,it is found that with the increase of prestatic load,the rock damage caused by the perturbation increases gradually.In particular,the influence of disturbance on rock is obviously increased after large deformation under prestatic load.The perturbation deformation under single axis is more disordered than that under confining pressure.With the increase of confining pressure,the ability of the specimen to resist disturbance deformation increases gradually.4)Create creep perturbation model based on basic model elements.When the stress is below the long-term strength,the Burger model is used to describe it,and the new model is constructed by connecting with the disturbance surge deformation element.When the stress is higher than the long-term strength,the Burger model,the nonlinear disturbance element and the disturbance surge deformation element are connected to construct the composite Burger model,and the experimental results of the confining pressure of 3MPa in chapter 4 are verified to verify the correctness of the model.