STUDY OF ACOUSTIC EMISSION CHARACTERISTICS OF LIMESTONE UNDER CYCLE UNIAXIAL LOADING- UNLOADING PERTURBATION
BAO Chunyan1，2，JIANG Annan1，TANG Chun?an2，LIANG Zhengzhao2
(1. College of Transportation and Logistics Engineering，Dalian Maritime University，Dalian，Liaoning 116026，China；2. School of Civil and Hydraulic Engineering，Dalian University of Technology，Dalian，Liaoning 116023，China)
Abstract：Take limestone samples from metro Line 2 as research objects，and study acoustic emission(AE) characteristics under uniaxial cyclic load-unload disturbance，which simulate the traffic load disturbance，then carry out numerical simulation of rock failure process under load-unload by RFPA2D. The results confirmed the existence of Kaiser effect of such limestone，also confirmed the existence of Felicity effect under loading- unloading. Loading and unloading theory will be applied to the rock acoustic emission precursor analysis，taken the Y value(load/unload response ratio，LURR) reach(close) to 1 as a precursor of failure characteristics of such rock. The AE energy of such stone accelerated release obviously. The numerical simulation shows evident Kaiser effect，and the corresponding AE event vividly. The comparison of the results of simulation and tests shows that，the two are the most closed when the coefficient of homogeneity m is 5. The results are expected to provide basis for construction safety and to avoid geological disaster in the underground works.
OBERT L，DUVALL W I. Micro-seismic method of determining the stability of underground openings[R]. Washington：United States Department of the Interior，1957.
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2011, Vol. 30 
