Experimental Research On Anisotropy Characteristics For Non-interpenetrated Jointed Rock Mass

In the process of long geologic effect，the rock mass was cut by structural planes withdifferent shapes and directions into discontinuous rock mass with certain structure, whichled to its complicated mechanical characteristic. In this paper, the non-interpenetratedjointed by sonic wave test, uniaxial compression test, the conventional three axialcompression test and unloading test, study the acoustic characteristics of jointed rock massand loading and unloading mechanics characteristics, the specific contents are as follows:1) The upgrading of test equipment, including the rock cutting machine to meet thetest requirements of the upgrade, cutting machine after transformation can cut differentjoint angle, different joint depth of rock specimen.2) Different connectivity and different angles of discontinuous jointed rockcompressional wave velocity test, to study the acoustic wave velocity change along withthe characteristics of joint connectivity, joint angle and attenuation rule. The results showthat with the increase of joint connectivity, P-wave velocity in non-penetrating velocity ofpropagation of jointed specimens in each angle joint angle were significantly decreased;decay rate sensitivity on the joint angle in longitudinal wave velocity (sensitivity with μsaid) followed by the size of: μ0°>μ30°>μ45°>μ60°>μ90°.3) The intact rock specimen and different connectivity (k=0.25, k=0.5, k=0.75),different angle (β=0°, β=30°, β=45°, β=60°, β=90°) non through different confiningpressure jointed rock mass test, uniaxial compression (5MPa,10MPa,15MPa,20MPa)under the conventional three axial compression test, unloading (pre peak unloading) test;study of different joint connectivity, different joint inclination of non-persistent jointedrock mass deformation, a loading and unloading conditions, parameters, strength failurecharacteristics, and with complete specimens were compared. The results show that non-interpenetrated jointed rock mass under loading and unloading conditions exhibitanisotropic mechanical properties anisotropy, and with increase of jointed connectivity rate,the performance of this anisotropy is more obvious.4) Non-interpenetrated jointed rock specimen in the loading and unloading test out ofthe mechanical properties, failure mode, mechanical parameters have obvious differences,the failure mechanism of rock mass with different loading and unloading state.5) A linear type of Mohr-Coulomb strength criterion, parabolic Mohr-Coulombstrength criterion and Hoek-Brown criterion can be the main surface interaction, force are compared, parabolic Mohr-Coulomb strength criterion and Hoek-Brown criterion canaccurately describe the non-penetrating the jointed rock specimen under loading andunloading conditions of main stress.6) According to the loading test of jointed rock mass, the single non persistent jointedrock mass unloading criterion, are discussed, the non-interpenetrated jointed rock mass isregarded as a kind of injury, according to the characteristics of the stress-strain curve ofrock damage process, damage variable is introduced, the loading and unloading curve isdivided into linear elastic, ideal elastic-plastic segment, strain softening, linear residualplastic flow of4sections, and derived the corresponding strain softening constitutivemodel.