| The mechanical properties and internal damage evolution of rock materials under external loads are largely controlled by the internal meso-structure.In order to better carry out the study of rock failure characteristics at meso-level,an equivalent crystal model with actual mineral distribution characteristics was constructed,and the effect of rock meso-structure parameters on fracture evolution was investigated by numerical simulation.Based on the contact branching information in the numerical model,a calculation method of fracture evolution evaluation factor is proposed,the fractures development degree of the rock is quantified.The research results are as follows:1)The digital model of rock can reflect the real meso-structure inside rock,simulate the meso-structure behavior of different minerals in the process of rock deformation and failure,and identify and quantitative analysis the mode of crack evolution and its mechanical mechanism in the process of rock fracture.2)The crack evolution mode is intergranular in the strong mineral crystals,in the weak mineral crystals,the crack evolution mode is “Intergranular + Intragranular”.The main crack network is formed when the distribution of strong and weak mineral crystals is concentrated,and the net-like crack network is formed when the strong and weak mineral crystals are distributed discretely.3)Compared with the bond strength,the crystal size has more obvious influence on the macro-mechanical properties of rock,a less influence on the development of internal fractures,and a greater effect on the formation of macro-crack network,but both of them can restrain the intergranular crack growth and promote the intragranular crack growth,and promote the development and formation of crack concentration band.4)The calculation method of fracture evolution evaluation factor constructed can quantitatively describe the fractures development degree,the results show that the crystal size has more significant influence on the fracture evolution than the bond strength.Figure 40;Table 31;Reference 63... |
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