In the study of early warning of backfill instability

the acoustic emission precursory characteristics have been recognized by many scholars. However

there are many forms of acoustic emission precursory characteristics

which have certain influence on the early warning of the backfill instability. Based on this

this paper attempts to establish a fixed form of early warning model of the backfill instability. First of all

based on the energy evolution characteristics and cusp catastrophe theory

an early warning model of backfill instability is constructed

and then the uniaxial compression acoustic emission verification test is carried out for backfill with different ash sand ratios. Experimental results show that the early warning state of backfill can be described by the interval composed of the catastrophe of dissipative energy and the catastrophe of releasable elastic strain energy

and the interval is defined as early warning interval. Moreover

the early warning intervals of backfill with different cement-sand ratios are unique

implying the model is extremely flexible and universal. The precursory characteristics of acoustic emission characteristic parameters with high recognition such as ringing counting rate are employed to verify the reasonableness of the early warning interval. It is found that the early warning interval calculated from the model is highly consistent with the time of the precursory characteristics of acoustic emission parameters

further proving the rationality and universality of this model and providing a new idea for the early warning of instability of backfill.