Study On The Correlation Between Fracture Energy Andgeometrical Characters Of Mesostructure Of Marble

Fracture energy is a very important quantity describing fracture behaviors of rock. Rock consists of mineral grains on the meso-scale. This kind of mesostructure governs the macro fracture energy. The determination of mesostructure on fracture energy comes from two aspects. One is the mechanical properties of mesostructure and another is the geometrical characters of mesostructure. To reveal the meso mechanism of macro fracture energy, the present dissertation studies the correlation between the geometrical characters of mesostructure and the macro fracture energy.To explore the effects of meso-structure geometrical characters(topology of grain interface network and particle size distribution) on the fracture energy and get ins ight into the micro mechanism of macro fracture energy of rock, the three-point-bending test is firstly carried out to obtain the fracture energy of marble. Then a rock slice is taken from fracture surface for SEM scanning in order to obtain the image of meso-structure of rock. Using the technique of digital image processing, the grain interface network and particle s ize distribution is obtained. Through the analys is on the interface network and particle size distribution, it is found that both the topology of interface network and the grain s ize distribution present a strong fractal feature. There exists a strong correlation between the fractal dimensions and macro fracture energy. The relationship between the fracture energy and the fractal dimension of interface network can be well characterized by the quadratic function while the relationship between the fracture energy and the fractal dimension of grain size distribution can characterized by the linear function. The macro fracture energy increases with the increas ing of the fractal dimens ion to some extent,the fractal dimension can describe the impact of meso-structure characteristics to the rock fracture energy quantitatively. The results of this study reveal a correlation between macro fracture energy and geometric characteristics of meso-structure, deepen the understanding on meso-mechanism of macro fracture energy.