Research On Modeling Method And Fracture Mechanism Of Three Dimensional Complex Particle Rock

Rock mechanics and engineering problems are three dimensional mechanical problems. Due to a large number of different types of heterogeneous materials with complex internal meso structure, such as rock, concrete and other structures of the particles and the structure of the space and the cracks, holes and other defects, and a variety of mesoscopic mechanics characteristic and defect structure of the rupture mechanism have important implications, makes the rock, concrete and other materials of the rupture process become a nonequilibrium and nonlinear three-dimensional mechanical problems. However, due to the limitation of the mathematical theory, laboratory tests and field observation test condition and technical, bring to the study of the three-dimensional failure process of rock great difficulties. So, numerical simulation has become one of the powerful tools to solve these problems. Establishing the numerical model is the key of the process of numerical simulation. Therefore, as far as possible using a method which express rock materials with different fine view of the morphological structures. Establish a 3D numerical model based on authentic materials meso structure, more intuitive, more comprehensive and more appropriate with the actual study on the mechanical properties of rock.In this paper, granite and concrete as the research object, using digital image processing technology to characterize the internal granule structure, hole and crack complex microstructure, combined with RFPA^2D-DIP software to establish the two-dimensional numerical model and numerical simulation. Access to the internal structure of concrete layer slice images with CT scanning technology, based on the numerical method of two-dimensional model, combined with RFPA3D-DIP software for the first time to establish a 3D numerical model of concrete defect with prefabricated pores and cracks, and the simulation of concrete uniaxial compression experiments, compared the numerical results and experimental results. The main research work is as follows:1. The analysis in the color space feature structure containing granite and concrete materials in digital image structure and defects of complex particles. The using of image recognition and image segmentation methods in digital image processing, which is digital image characterization of meso structure within the material.2. Based on the microstructure characterization of the material, the two-dimensional numerical model of granite and concrete is established by the RFPA^2D-DIP program. Numerical simulation and experiment analysis of influence of particle morphology structure and defects such as holes and cracks and fracture mechanics properties of composites.3. The inner structure of concrete for prefabricated crack, holes and other defects by CT scanning technique layer slice image. Based on the meso structure characterization on each layer image characterization information from tensile forming a layer of three-dimensional model data. A three dimensional structure model of concrete containing defects is established by using the method of data layer by layer stacking.4. The three-dimensional structure model of concrete is combined with RFPA3D-DIP to establish a numerical model which can reflect the real microstructure of the materials. Simulation analysis of influence and defects of aggregate particles under uniaxial compression on the rupture process. The numerical calculation results and experimental results were compared and validated from the crack location and rupture mode as well as the surface, both have good consistency. Using RFPA3 D specific model cutting slicing model, analysis model of internal crack propagation characteristics.Based on the research on the reconstruction method of the structural model of granite, concrete and other heterogeneous materials, the numerical model is established with numerical simulation software. The numerical results and experimental results were verified, the results on the mechanical properties of rocks, granite and other research materials and rupture mechanism has important theoretical significance and practical application value.