EXPERIMENTAL STUDIES OF MECHANICAL PROPERTIES OF TWO ROCKS UNDER DIRECT COMPRESSION AND TENSION
LI Diyuan1，2，LI Xibing1，LI C CHARLIE2
(1. School of Resources and Safety Engineering，Central South University，Changsha，Hunan 410083，China； 2. The Norwegian University of Science and Technology，Trondheim 7491，Norway)
Abstract：Uniaxial tests are carried out on two types of hard and soft rocks by using Instron 1342 hydro-servo- controlled machine，including uniaxial compression tests and direct tensile tests. The mechanical properties of these two rocks are obtained. The uniaxial compression strength(UCS) and the uniaxial tensile strength of the two rocks are compared. Both the axial strain and the lateral strain of the specimens are logged during the tests；and the acoustic emission(AE) of the specimens is monitored by the AE sensor. The stress-strain curves and the AE counts rate curves of the two rocks are obtained under direct compression and tension. The AE characteristics of the two rocks are studied. It is found that under direct tension there are almost none of AE events during the loading process until close to the final failure. The variations of elastic modulus and the Poisson¢s ratio with the applied loads are compared between the two rocks. It shows that under compression，the initial elastic modulus of hard rock is relatively small at the beginning stage and then increases to a stable value when the stress is within its 80% of UCS；and then it decreases until the final failure. By contrast，under tension，the elastic modulus of hard rock is relatively large at the beginning stage and then decreases with loading. The Poisson¢s ratios of the two rocks are both ranged from 0.2 to 0.3 under compression；but it becomes very small and can be neglected under tension. The fracture angles，the internal friction angles and the cohesions of the two rocks are compared；and the failure modes of the rock specimens are discussed. Finally，the tensile fractures of typical rock specimens are measured by a 3D surface measurement machine. The microstructure and the roughness profile of the tensile fractures are obtained.
李地元,李夕兵，LICCHARLIE. 2种岩石直接拉压作用下的力学性能试验研究[J]. 岩石力学与工程学报, 2010, 29(03): 624-632.
LI Diyuan1，2，LI Xibing1，LI C CHARLIE2. EXPERIMENTAL STUDIES OF MECHANICAL PROPERTIES OF TWO ROCKS UNDER DIRECT COMPRESSION AND TENSION. , 2010, 29(03): 624-632.
