Experiment and Mechanical Mechanism of Interference Effect between X-shaped Discontinuous Intersecting Joints

Conjugated X-shaped jointed rock masses are widely distributed in nature. An accurate understanding of the interference effect between conjugated X-shaped intersecting joints is very important for the safety and stability of related rock mass projects. To study the influence of intersecting joint interference effects on the mechanical properties of rock masses, it makes specimens of similar materials for jointed rock masses, changes the inclination angle and length of the primary and secondary intersecting joints and conducts indoor model tests and theoretical analysis as well. The research results show that the X-shaped jointed rock mass wing cracks mainly propagate along the tip of the main joint, while the expansion of the secondary joint is suppressed. The interference effect between the same-inclined intersecting joints causes the stress intensity factor of the main joint tip to increase, and when the inclination angle of the secondary joint is 45°, the interference effect is the most obvious. When the angle between the primary and secondary joints is 60°, the secondary joint has the strongest shielding effect on the stress intensity factor at the tip of the primary joint. When the angle between the primary and secondary joints is 90°, there is no intersecting joint interference effect. When the angle between the primary and secondary joints of the opposite tendency is greater than 90°, the interference effect of the intersecting joints causes the stress intensity factor at the tip of the primary joint to decrease.