The effect of crack characteristics on the mechanical properties and energy characteristics of coal-rock composite structure

With the gradual increase of coal mining intensity, many pillars need to be left near stope. The stability composite structure and their overlying strata determines safety whole stope surface. This paper conducts uniaxial compression tests on coal-rock structures with same lithology height ratio finds structure’s mechanical properties failure characteristics have greater discreteness. Combining CT images rock coal, it is concluded that main reason for discreteness test results different crack in specimen specimen. Therefore, this uses PFC numerical simulation software analyzes influence properties, characteristics, impact energy index structure. sensitivity factors are used analyze angle, length, number position peak stress, total number, research can provide a theoretical basis guidance preventing instability pillar-roof