Abstract:The meso-crack in brittle rock is one of the important factors leading to its instability and failure. It is of great significance to study the propagation and penetration of micro-crack after loading based on meso-mechanism. There are mainly type Ⅰ-Ⅱ compound cracks in brittle rocks. at present, there are relatively few studies on the influence of the propagation and penetration of the composite cracks on the instability and failure of rock under compression. According to the maximum circumferential tensile stress criterion, combined with the mode Ⅱ crack intensity factor under tension-shear combined action, the expression of the intensity factor of mode Ⅰ-Ⅱ composite crack is transformed in this paper. the expression of the intensity factor of mode Ⅰ-Ⅱ composite crack affected by crack parameters is obtained. Through the relationship between crack intensity factor and crack propagation, the relationship between stress and crack propagation length with the influence of mode Ⅰ-Ⅱ composite crack parameters is obtained. combined with the damage-strain relationship, the stress-strain relationship affected by the crack parameters is derived.?By comparing the conventional triaxial experimental results of marble, it is found that the two results are in good agreement with each other, which fully verifies the rationality of the model.?The results show that the bearing capacity of rock decreases with the increase of initial damage, crack size, and airfoil crack length, and increases with the increase of friction coefficient between cracks.?And in the case of the same axial pressure, the crack propagation length decreases with the increase of confining pressure, indicating that the confining pressure can effectively restrain the propagation and penetration of internal cracks in the rock.?In this paper, the influence of mode Ⅰ-Ⅱ compound crack parameters on the bearing capacity of rock are explained from the point of view of meso-mechanics, and the crack opening angle is taken into account, which provides a certain reference value for studying the compressive failure of rock from the meso-mechanism.