Study On The Prediction Models Of Volume Strain And Damage In Millisecond Grades Of Different Rock Mass

This thesis depends on different working condition of dynamic load on the rock mass.Such as waveform frequency conversion variable peak load or loops and uninstall simulated earthquake,rising and dropping drastically the reservoir water level,caused by blasting vibration,construction operation period of mechanical vibration and so on.Then study on the transverse strain rate,volumetric strain and damage of sandstone,limestone and mudstone are simulated in millisecond scale.In this paper,the main research results are as follows:1)The relative parameters such as the dynamic Poisson's ratio,the force rate,the axial deformation rate,the lateral deformation rate and the instantaneous elastic modulus under millisecond dynamic action are compared and studied,which provide the data support for the rock mechanics test and the prediction of the stability of the engineering rock mass.2)Under the same n value,the increase of the displacement rate will have a linear acceleration effect on the increase of the force acceleration.Therefore,in engineering practice,according to the law of this change,the difficult force acceleration can be predicted from the easily measured displacement rate,and then the law of the variation of the force in the sandstone is predicted.3)The linear relationship between the dynamic Poisson's ratio and the immediate load,the immediate transverse length and the immediate axial height,respectively,are obtained respectively under the conditions of the peak load and unloading section of the peak load and unloading section under the conditions of triangular wave and sinusoidal wave,,and the number of these linear relationships under each load peak has obvious correlation with the corresponding peak load.The linear relationship between these coefficients and the peak value of different loads under different conditions is obtained.On the basis of a small number of cyclic tests,the dynamic parameters of rock can be obtained,and the linear relationship between the dynamic Poisson's ratio and the three parameters under different load peaks is predicted.4)For the 0.1Hz triangle wave and the sinusoidal wave loading and unloading,the lateral displacement and volume strain are simulated in milliseconds.Through a small amount of experimental data under the peak loading force,there is no need to measure the relative displacement value,and the rock samples with different waveforms under different loading peaks can be obtained under different k Nown pieces.The volume strain and the change of damage variable make a millisecond accurate prediction model.5)This paper defines and divides the stress-strain asynchrony time and the axial strain-lateral strain asynchrony time respectively under the triangle wave and sine wave loading,and analyzes the difference of the corresponding parameters of various rock masses under different wave,frequency and different load peak values,and puts forward that the time interval of speed is not synchronous.Finally,the effect of asynchrony on the volumetric strain and energy of rock samples is discussed.