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Abstract Acoustic emission tests under triaxial compression of limestone were carried out by MTS815 servo-controlled rock mechanical test system and AE21C acoustic emission monitor. The characteristics of limestone damage evolution under triaxial compression are analyzed through acoustic emission parameters. The results show that：(1) Under the same experimental condition，the maximum acoustic emission ringing counts and energy with the detector inside the confining chamber are more 27.0% and 32% higher than that outside the confining chamber，respectively. The more comprehensive and real acoustic emission signals can be received with the detector inside the confining chamber. (2) The confining pressure can make the acoustic emission activities decrease in the stage of compaction. The time of acoustic emission ringing counts reaching its highest value lags behind the time of the macroscopic failure of the specimen，which indicates that the confining pressure not only improves the shear strength of rock，but also its bearing capacity after the peak stress. (3) The rock damage evolution model is established with the acoustic emission ringing counts under triaxial compression. The damage evolution process of rock can be divided into following four stages：initial damage stage，stable damage evolution and development stage，damage speeding development stage and damage failure stage. The acoustic emission activities are less in the initial damage stage. In the stable damage evolution and development stage，the acoustic emission activities begin to be active with the increase of the acoustic emission ringing counts and energy. In the damage speeding development stage， the acoustic emission activities become extremely active；and the acoustic emission ringing counts and energy reach their peak values short after the macroscopic failure. In the damage failure stage，the rock still has bearing capacity and some acoustic emission events are still active.
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Received: 22 November 2012
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2014, Vol. 33 
