MESOSCOPIC SIMULATION OF RELATIONSHIP OF ACOUSTIC EMISSION AND COMPRESSIVE DEFORMATION BEHAVIOUR IN SANDSTONE UNDER CONFINING PRESSURES EFFECT
MU Kang1，LI Tianbin2，YU Jin1，2，CAI Yanyan1，2，LIU Shiyu1，TU Bingxiong1，JIANG Haochuan1
(1. Institute of Geotechnical Engineering，Huaqiao University，Xiamen，Fujian 361021，China；
2. State Key Laboratory of Geohazard Prevention and Geoenvironment Protection，Chengdu University of Technology，Chengdu，Sichuan 610059，China)
Abstract：The macro-mechanical parameters and acoustic emission(AE) data of sandstone under various confining pressures were obtained by triaxial compression tests and AE tests. According to laboratory testing results，the spatial and temporal distributions of AE in compression deformation of sandstone under different confining pressures were simulated from mesoscopic aspect by using the particle flow code(PFC2D). Considering different development patterns of the tension and shear cracks，the relation between AE characteristics during the compression deformation of sandstone and the brittle-ductile transition is established. The study shows that under low confining pressure，AE tests experienced the“quiet period”，“developing period”，“erupting period” and “dropping period”. The cracks were mainly constituted by tension cracks with a few shear cracks，which were concentrated in the shear zone. Under high confining pressure，no obvious drop appeared after“erupting period”of AE. Before the peak strength，the dispersed shear cracks were more than the tension cracks，but concentrated connected tensile cracks were more than the shear cracks after the peak strength. The AE mainly based on tension cracks reflects a brittle characteristic of failure. And when numbers of shear cracks are developed，it indicates that the specimen is transited from brittle to ductile one.
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2014, Vol. 33 
