Precursor information study on acoustic emission characteristics of marble under uniaxial cyclic loading-unloading

In the engineering construction,the rock mass is often under cycle loading-unloading. The prediction of the rock damage under cycle load-unloading has an important practical significance. Two different cyclic stress paths are set to study the acoustic emission characteristics of the Yunnan white marble under cycle loading-unloading. The study shows that:during the unloading phase there is no apparent acoustic emission in the early stage,the acoustic emission appears during the intermission period. The change trend of the Felicity value is relatively consistent under the differ- ent stress paths:the Felicity values gradually reduce with the increase of stress level. The Felicity values of the stress limit constant load-unloading scheme are relatively lower than the stress difference constant load-unloading scheme, which shows that the first scheme causes more serious damage to the rock. The b value can be divided into three parts during the whole cycle loading:the b value decreases with the increase of stress when the rock is under lower stress level,and then the b value fluctuates within certain extent showing that the cracks within the rock goes through a rela- tively stability development period. Before the rock damage,the b value shows a certain degree of increase. In a single cycle unloading the b value presents a V-shaped distribution and the b value has a dramatic change before the destruc- tion of rock. b value and Felicity value have a certain consistency and diversity,the use of the combination of these val- ues can improve the accuracy of rock damage prediction.