Research on classification of rock tensile-shear fracture based on acoustic emission RA-AF values and kneedle algorithm
The accurate determination of the boundary equation is crucial for classifying and identifying cracks in the process of rock fracture using the RA(Rise Time)and AF(Amplitude Ratio)values of acoustic emission.The granite shear acoustic emission monitoring experiments were carried out.Based on the crack classification method using RA-AF,the influences of the slope k and intercept b of the boundary equation on the crack classification results were analyzed.Utilizing the turning point detection algorithm for curves(kneedle algorithm),a method for accurately determining the boundary equation was developed,and the crack classification results were analyzed.The results indicate that both the slope k and intercept b of the boundary equation have an influence on the crack classification results,which is related to the magnitudes of the two values.There exist critical values for both the critical slope and critical intercept.When these values are smaller than the critical values,the classification results are greatly affected,whereas when they exceed the critical values,the classification results are almost unaffected.The kneedle algorithm for curve inflection point detection can effectively determine the critical points of the boundary equation slope and intercept,providing a method and basis for accurately determining the critical slope and intercept in the boundary equation.Compared to the boundary equation without intercept,if the boundary equation has an intercept b,the proportion of shear cracks will increase by approximately 20％.The research findings provide a basis for determining the boundary equation for classifying rock tensile-shear cracks using RA and AF values,which contributes to the application of this method in rock mechanics.
rock mechanicsacoustic emissionRA valueAF valuecrack classification
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