Experimental research on characteristics of deformation and failure of surrounding rock of roadway in deep mine under influence of principal stress evolution

It is necessary to study the characteristics of deformation and failure of surrounding rock of roadway under influence of the principal stress for roadway support. Based on the surrounding rock of roadway with high horizontal stress in a deep mine, the characteristics of shear and slip with support method are physically simulated by using a large-scale three-dimension test system and principal direction strain sensors. The simulation method of loading first and then excavation is carried out. At the same time, the influences of degree and direction of the principal direction stress are taken into account. The results indicate that the roof and bottom of roadway fail due to pressing and slipping under the high horizontal stress. The development of failure range exhibits 'wedge' shape. By observing the section of model, there are different shear slip fractures with the form of symmetric helical segments at the roof and bottom during drilling. The fractures expand to the wall and cross at last. The shear failure zone is formed at the surrounding rock. The shear slip fractures formed by the high horizontal stress are linked to the evolution of the principal stress by analyzing the direction and degree of the principal stress. The evolution of the minimum principal stress plays an important role in the formation of shear slip fractures.