Experimental Study on the Mechanical and Acoustic Characteristics of Cemented Backfill with Unclassified Tailings at Different Curing Ages under Uniaxial Compression

Abstract

In order to study the influence of the cement–tailing ratio and curing age on the mechanical properties of cemented backfill with unclassified tailings and improve the accuracy of the backfill monitoring method, the mechanical characteristics of the failure process of cemented backfill with unclassified tailings at different curing ages were studied using the acoustic emission and infrasound method. The results show that the peak strength and modulus of elasticity of backfill are positively correlated with the curing age. During the failure process of cemented backfill with unclassified tailings, the acoustic emission ringing count shows a “stabilizing–rising–falling–rising” trend, and the infrasonic ringing count will have a “multiple peak” phenomenon. The ib value of the acoustic emission signal generally increases with the extension of the curing age. The ib value of the infrasonic signal generally has a negative correlation with the increase of the curing age. When the ib value of the acoustic emission and infrasonic wave all start to decline in a jumping manner, this indicates that the backfill is about to be damaged. The dominant frequency ratio of acoustic emission signals (FAE) is distributed between 0–4 during the failure process, and the total number of FAE shows the phenomenon of “first decreasing and then increasing” with the curing age. The dominant frequency ratio of infrasonic signals (Fs) is distributed between 0–6. During the failure process of cemented backfill with unclassified tailings, the quantity ratio of class A and B of acoustic emission signals shows a gradually increasing trend, and the quantity ratio of class A and B of infrasonic signals shows a “decreasing–increasing–decreasing” trend, and the quantity ratio of class A and B of acoustic signals shows a sharp increase at the stage of entering the crack’s unstable growth stage.

Study on triaxial compression performance and damage characteristics of fiber-reinforced ecological matrix cementing gangue gypsum fill material

“…Deng et al [21] revealed the mechanism of the strength of cement backfill influence on the filling rate through laboratory tests and theoretical analysis, expounded the calculation principle of the target filling rate of multi-scene cement backfill, and finally formed the dynamic design method of the strength demand of cement backfill guided by the filling rate control in coal mine goaf. Zhao Kang et al [22], Liu L et al [23], Zhao Kui et al [24] carried out theoretical research on the strength of backfill under different conditions, and achieved a series of results. Xu Wenbin et al [25], Li E et al [26], Xu Jun et al [27] through a large number of experimental studies show that: fiber can enhance the strength of the filling body, the influencing factors are fiber type, content and fiber length.…”