Study On Creep And Damage Law Of Deep Rock

With the rapid development of the national economy and national defenses construction, underground exploitation depth trends much more deep levels. Kilometer or even several kilometers coal mines and tunnels can be found everywhere. Deep rock mass dues to it's particularity of physical geography environment and complexity of it's stress field has become a problem that must be carefully taken into consider and study in engineering practice. In this paper combined with "the study on coalrock dynamical disaster time effect of deep exploitation" which supported by National Natural Science Foundation of China, experimental study and theoretical analysis were used to study creep and damage property f deep limestone, gained a some Practical Significance research results.The experiment of deep limestone specimen were first carried out under uniaxial and triaxial compression load which under natural conditions, the complete stress vs strain curve of rock and it's damage failure condition were analysised. Based on the study of basic mechanics properties of deep limestone, the basic mechanics parameters were determined.Creep experiment of deep rock specimen under three different uniaxil loads were carried out. At the mean time the acoustic emission signal was monitored by acoustic emission instrument at the process of compression as well. In the paper deep limestone creep damage properties under three different loads was analysised, meanwhile the acoustic emission during creep process was analysised too. At last was conclusion and discussion about the creep and damage of deep limestone and the properties of acoustic emission. The curve of accumulated acoustic emission ringing count vs time and the curve of creep strain vs time have same tendency, the accumulated acoustic emission damage generation and the AE signal level represents the degree of the creep damage.Through triaxial creep test shows that the rock microcrack nucleation and growth was relatively dependent on deviatoric loads and confining pressures. At the same deviatoric loads the steady creep ratio and damage evolvement increased with increasing of confining pressure. The expands of microcracks increased with increasing of deviatoric loads at same confining pressure. The power law type creep constitutive model was used in this paper and by the fitting got the parameters of this model. Compared with experiment data, result show that the power law type creep constitutive model can better simulate rock creep behavior except for the third creep stage.Finally, the power law type creep model was used to numerical simulation deep tunnel creep and damage property at different depth levels. The horizontal and vertical displacement deformation and damage properties of the tunnel wall rock have been analyzed. The result show that FLAC^3D three dimension Fast Lagrangian Analysis of Continua code can simulate then whole process of structure which from elasticity to plasticity yield, unstable failure up to larger deformation expediently.