Influence of Loading Rate on the Mechanical and Failure Characteristics of Rock-Coal-Rock Combination Body
Aiming at the problems of complexity of the failure of rock-coal-rock composite structures in mines under different load conditions and others,the strength and failure characteristics of rock-coal-rock combination structures under different loading rates are studied based on the discrete element method.The internal stress distribution characteristics of the samples at different crack numbers and the bearing evolution process of sandstone and coal rock structures are analyzed.The results show that the peak stress of the rock-coal-rock combination body increases approximately linearly with the loading rate,the peak strain shows an overall accelerating increases trend with the loading rate,and the elastic modulus show an overall an increasing trend of deceleration with the loading rate;When the loading rate is relatively high,the stress strain curve of the samples shows significant fluctuations;As the loading rate increases,the AE events of the samples gradually become more intense during the increasing period and peak period of acoustic emission;The maximum crack number in the samples shows an overall linear increases trend with the loading rate.Under low stress levels,it is carried by the coal rock structure,and after reaching the peak strength,the bearing structure gradually transforms from the coal rock structure to the sandstone structure.
rock-coal-rock combination structurediscrete element methodstrength characteristicfailure evolution
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