|
Abstract In order to explore the fatigue properties and its influence factors，an evolution model of damage accumulation was established and the effect of static loading on the damage accumulation of rock under cyclic impaction was studied. Compared with the S-shaped growth curve，a model of the damage evolution of rock having a trend of rapid rising，steady development and sharp rising subjected to the coupled static-cyclic impact loadings was established using the inverse transformation of logistic function. The physical meanings of the parameters in the damage accumulation model were determined by analyzing the variation of the curves with three parameters fixed and one varying. The objective function for fitting the damage model was established based on the approximation theory of the least squares. After programmed with Matlab，the data fitting of the damage accumulation model was calculated and the damage accumulation model was proved to be correct by the test data. The evolution model of damage accumulation was used to fit the experimental data of rock damage upon cyclic impaction under different static loadings. The effect of static loading on damage accumulation was studied through analyzing the relation between the fitting parameters and the static loadings. The axial pressure and the confining pressure have great effect on the trend of dynamic fatigue damage of rock. The change of axial pressure has smaller influence on the parameters ?，? and ? with the confining pressure increasing. The change of confining pressure always influences evolution the trend of dynamic damage accumulation no matter how much the value of the axial compression is.
|
|
Received: 31 July 2013
|
|
|
|
2014, Vol. 33 
