EXPERIMENTAL AND NUMERICAL STUDIES OF MECHANICAL RESPONSE OF PLATE-SHAPE GRANITE SAMPLES CONTAINING PREFABRICATED HOLES UNDER UNIAXIAL COMPRESSION
LI Diyuan1，2，LI Xibing1，LI C Charlie 3，WONG Louis Ngai Yuen2
(1. School of Resources and Safety Engineering，Central South University，Changsha，Hunan 410083，China；2. School of Civil and Environmental Engineering，Nanyang Technological University，639798，Singapore；3. Department of Geology and Mineral Resources Engineering，The Norwegian University of Science and Technology，Trondheim 7491，Norway)
Abstract：The uniaxial compression tests of plate-shape granite samples containing two prefabricated holes on each side，prepared from Iddefjord granite blocks in Norway，are carried out by Instron hydraulic servo control testing machine in laboratory. The axial stress，axial and lateral strain，acoustic emission(AE) counts and failure modes of the samples are monitored during the tests. The splitting cracks occur near the holes′ vertical surface and parallel to the loading direction when the loading stress increases to a certain value. Some characteristics of rockburst phenomena such as rock block ejection and slabbing failure can be observed around the prefabricated holes under high compressive stress. The failure modes of samples always initiate from the splitting fractures around the holes under uniaxial compression. By observing the AE counts rate curve，it is shown that more jumping mutation points appear in the curve than that of intact rock samples. Based on the experimental studies，numerical models are validated by FLAC3D(3 dimensions fast lagrangian analysis of continua). The principal stresses distributions in the samples are obtained by the elastic model analysis，while the failure process is studied by the Mohr-Coulomb strain softening model. The modes of failure zones are monitored and characterized by the AE count events. Most failure zones are failed in tension and connected together to form as splitting fractures parallel to the vertical boundary of the holes. The numerical results are almost the same as the laboratory tests. The research results，to some degree，reveal the formation mechanism of slabbing fractures，which are usually parallel to the excavation boundary surrounding underground openings in hard rocks under high in-situ stresses.
李地元1，2，李夕兵1，李春林3，王毅远2. 单轴压缩下含预制孔洞板状花岗岩试样力学响应的试验和数值研究[J]. 岩石力学与工程学报, 2011, 30(6): 1198-1206.
LI Diyuan1，2，LI Xibing1，LI C Charlie 3，WONG Louis Ngai Yuen2. EXPERIMENTAL AND NUMERICAL STUDIES OF MECHANICAL RESPONSE OF PLATE-SHAPE GRANITE SAMPLES CONTAINING PREFABRICATED HOLES UNDER UNIAXIAL COMPRESSION. , 2011, 30(6): 1198-1206.
DIEDERICHS M S. Instability of hard rock masses：the role of tensile damage and relaxation[Ph. D. Thesis][D]. Waterloo，Ontario，Canada：University of Waterloo，1999.
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2011, Vol. 30 
