Study On The Cracks Developing And Distribution In The Surrounding Rock Of Deep Roadway Group

In practical geotechnical engineering problems,due to the existence of primary fractures in the rock mass,when the stress of the rock mass is lower than its failure strength,the primary fractures in the rock mass gradually expand,and accompanied by the generation of secondary fractures.Because of the expansion of the primary fractures and the generation of this fracture and the communication between the fractures,the rock mass is unstable and damaged.There are also a large number of cracks in the surrounding rock of the coal mine roadway.Under the action of stress,the fracture zone of the surrounding rock expands,which affects the stability of the surrounding rock of the roadway.In this paper,the influence of fracture parameters on fracture propagation form,failure mode and strength of rock mass under compression is analyzed;the evolution and breakthrough law of fracture propagation in rock mass are analyzed by theoretical analysis and numerical simulation,and the influence of fracture on the distribution characteristics of fracture area of deep roadway surrounding rock is further analyzed by numerical simulation;the conclusion is obtained by drilling and peeping on site The influence of fracture on the distribution and evolution of deep roadway group fracture area.The following conclusions are drawn:(1)According to the expansion form,the fractures can be divided into three basic types: type i-open,type ii-sliding and type iii-tearing.Because of the large stress,the surrounding rock fractures of deep roadway usually belong to type I-II composite fractures.Due to the influence of fracture parameters and stress,tension wing crack,shear wing crack and tension shear mixed wing crack are usually produced when the fracture is expanding and expanding,and different wing cracks lead to different failure modes of rock mass.(2)The dip angle and opening degree of the fracture will have an effect on the expansion form,failure mode and strength of the rock mass.Among them,the fracture obliquity has a greater impact on the fracture mode and the fracture expansion form;the fracture opening has a greater impact on the strength of the fractured rock mass,but a smaller impact on the failure mode and the fracture expansion form of the rock mass.(3)Through the numerical simulation,the evolution and communication law of the surrounding rock fracture of the deep roadway are analyzed,and the feasibility of the simulation is determined by the comparison of the experimental results.The influence law of the factors such as the fracture angle and the fracture spacing on the distribution characteristics of the surrounding rock fracture of the deep roadway is further analyzed.(4)Through the numerical simulation analysis of the deep roadway group surrounding rock under the influence of the mining of the two flank working faces,the law of the surrounding rock fracture expansion and evolution,the law of the development of the plastic zone;through the field drilling peep obtained the plastic zone range of the roadway group and the distribution characteristics of the surrounding rock fracture of the roadway group at a certain stage,combined with the numerical simulation results,the final distribution characteristics and the plastic zone range of the surrounding rock fracture of the roadway group were determined,It provides theoretical guidance for later roadway support.There are 91 figures,15 tables and 101 references in the dissertation.