Study On Triaxial Compression Creep Of Red Sandstone Under Dynamic Disturbance

Rock damage in underground tunnels and mountain mine activities has occurred from time to time.In the mine activity,the surrounding rock is often in a state of external force disturbance and creep action,and its deformation and characteristics are different from single creep deformation and single disturbance deformation.In response to this,the research on the influence of dynamic load disturbance on rock creep was carried out,and related experiments,theoretical and numerical simulations were carried out to investigate the influence of dynamic disturbance on long-term deformation of rock mass engineering,and to predict the long-term surrounding rock of engineering and make a reference for the deformation.The main content and concluding results are as follows:(1)The conventional triaxial compression test of indoor red sandstone is carried out by TFD-2000/D dynamic disturbance electro-hydraulic servo rock triaxial test system.The physical and mechanical properties of red sandstone are studied.The triaxial compressive strength,elastic modulus,shear modulus,internal friction angle and cohesion of the red sandstone were obtained.According to the experimental data and results analysis,the selected red sandstone is determined to be brittle hard rock.(2)The triaxial compression creep perturbation test of red sandstone was carried out,and the triaxial creep deformation characteristics of red sandstone after being subjected to disturbance load were studied.The concrete performance is as follows:the higher stress level contributes to the creep of the rock.After the creeping rock is subjected to the disturbance load,the rock will have irreversible axial deformation and lateral deformation,which will lead to sudden increase of strain and cause disturbing cumulative strain increment.The first disturbance cumulative strain increment in the lateral and axial directions is greater than the second disturbance cumulative strain increment.The magnitude of the cumulative cumulative strain increase is related to the stress level and the disturbance load,but the influence of the disturbance load amplitude is the main cause.The cumulative strain increment of theaxial disturbance is not obvious with the confining pressure condition,and the cumulative strain increment of the lateral disturbance decreases with the increase of the confining pressure.(3)Based on the Nishihara model,the disturbance cumulative strain increment is introduced to establish the creep disturbance constitutive equation,and the error between the theoretical value and the experimental measured value is small.Combined with statistics and damage mechanics,the statistical damage constitutive relation of rock creep disturbance is established.The theoretical curve agrees well with the experimental curve,and the error is within reasonable range.The wave velocity test showed that the rock creep disturbance caused damage.(4)Using the finite element analysis software ANSYS,numerically solve the test,and simulate the long-term creep of the red sandstone sample after the disturbance load,and explore the long-term deformation effect of the disturbance on the rock creep.