The effect of meso-structure heterogeneity in material on the mechanical behavior of rock is studied in this paper, using Discrete Element Method and Weibull distribution model. Several triaxial compressive tests are conducted. Different meso-structure distributions are used. It is shownby numerical tests that the different internal meso-structure distribution can have considerable effects on the compressive strength, crack initiation stress and stress-strain relationship, and other macro-properties. The micromechanical behavior of rock samples is affected by the distribution of internal meso-structure parameters as well. The deformation and failure of rock is simulated by tracing the extension of the microscopic cracks and the micromechanical behaviors. Results demonstrate that the meso-structure heterogeneity have considerable effects on the mechanical behavior of rock.
The constitutive relation of rock has always been the focus of geotechnical research, with many kinds of models being found. However, most of the existing models cannot reflect the real behavior of rock in the force-deformation process actually. Rock and soil under complex geological conditions often exist in deep rock mass with high stress, so that their mechanical deformation properties are often non-linear, ductility and nonuniform.
The modeling and application of discrete element method in geotechnical engineering have undergone a relatively mature development, since itwas initiatively proposed by Cundal (1971). The discrete element modeling method is widely used in establishing models to trace the emergence and development of the microscopic cracks, estimate the ultimate strength, predict the body changes during force deformation process and so on.
Many international scholars have researched the application of the discrete element method in geotechnical engineering. Cho N, Martin CD et al (2007) explored the influence of the clustering characteristics for particles of rock and soil on the deformation and failure of corresponding materials. Diederich MS (2000) did research into the instability of hard rock specimens in tensile failure. Griebel M, Knapek S et al (2007) adopted numerical simulation and comparison to study the particle settings, algorithm selections and application of parallel computing in the calculation of dynamic characteristics for particle materials. Hazzard JF, Young RP (2000) modeled the mechanical properties of meso-structure to research its deformation and failure characteristics. Hoek E, Brown ET (1998) did some practical simulations and estimates on the strength of the rock specimen. Kazerani T, Zhao J (2010) fitted the failure of brittle materials using the method of bonding particles, compared and analyzed the influence of different meso-structure parameters on the deformation and failure of brittle materials. Jing L, Stephansson O(2007) systematically proposed basic principles of the theory and application of the discrete element model in geotechnical engineering.