Meso-Damage Mechanism of Strength and Deformation Characteristics of Typical Sandstone in Xinwen Coalfield

Geotechnical engineering problems will cause asymmetric deformation of surrounding rock, which is not conducive to the stability of rock mass. In order to study the meso-damage mechanism of rock strength and deformation characteristics, taking three kinds of typical sandstone as examples, the meso structure images of sandstone were obtained by JSM-6510LV scanning electron microscope (SEM). According to the meso-structure images and fractal theory, MATLAB was compiled to calculate the fractal dimension of the meso-structure images of the three types of sandstone. The uniaxial compression test of sandstone is carried out by using the Shimadzu electronic universal testing machine. The mechanical parameters of three types of sandstone are obtained. By comparing the relationship between fractal dimension and mechanical parameters, the correlation between strength and deformation characteristics of sandstone and mesostructure is analyzed. The results show that sandstone has the characteristic of self-similarity. The fractal dimension of sandstone decreases with the increase in magnification. The macro-mechanical properties of sandstone are closely related to the meso-structure. The strength characteristics of sandstone are inversely proportional to the fractal dimension. The greater the uniaxial compressive strength and elastic modulus, the smaller the fractal dimension. The damage problem of sandstone can be characterized by critical damage value, which is proportional to the fractal dimension; the larger the fractal dimension, the more serious the internal damage of sandstone.