Experimental Study on Creep Acoustic Emission Characteristics of Tailings Cemented Backfill Under Three-Point Bending
In order to study the creep characteristics of tailings cemented backfill under three-point bending,the flexural strength of backfill with cement-sand ratio of 1∶4,1∶6 and 1∶8 was measured by three-point bending test.On this basis,the acoustic emission test of three-point bending creep with graded loading was carried out,and the three-point bending creep characteristics and acoustic emission characteristics of tailing cementeds backfill under different cement-sand ratio and different load levels were studied.The results are concluded as follows.Firstly,the whole process of three-point bending creep of tailings cemented backfill is characterized by three creep stages:deceleration,steady state and acceleration.The backfill with cement-sand ratio of 1∶4 and 1∶6 enters the accelerated creep stage at the 7th load level,and the backfill with cement-sand ratio of 1∶8 enters the accelerated creep stage at the 5th load level.Secondly,with the increase of load level,the instantaneous creep amount,creep deformation amount and creep rate of tailings cemented backfill continue to increase.The larger the cement-sand ratio,the weaker the creep deformation ability of the backfill.Finally,with the increase of load level,the impact number,ringing count and energy value of acoustic emission decrease first and then increase.The backfill with cement-sand ratio of 1∶4 and 1∶6 reaches the minimum value at the 4th load level,and the backfill with cement-sand ratio of 1∶8 reaches the minimum value at the 3rd load level.The larger the cement-sand ratio of the backfill,the more acoustic emission signals and the greater the acoustic emission energy generated during creep fracture failure.
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