Dynamic stress distribution and energy evolution characteristics of deep roadway surrounding rock under dynamic loads
After excavation of the roadway,the concentrated distribution of the in-situ stress in the surrounding rock and the disturbance of the external dynamic load are two important factors that affect the safety and stability of the roadway.Based on the finite element mod-el and the implicit-explicit computing function of LS-DYNA,the mechanical response of the rock roadway with initial stress of 10,30 and 50 MPa under the action of dynamic load were analyzed.The dynamic stress distribution,energy change and evolution law,as well as dynamic deformation and damage characteristics of the surrounding rock of the roadway were obtained.Results show that the dynamic compressive stress concentration mainly distributes near the top and bottom corners of the roadway under the action of dynamic load,and while dynamic tensile stress concentration is mainly distributed on both sides of the roadway.The compressive stress concentration de-gree decreases with the increase of the initial stress,and there is no obvious change in the tensile stress concentration areas.Particle dis-placement and vibration velocity of the surrounding rock on the incident side of dynamic load are always higher than those on the trans-mission side.As the initial stress increases,the displacement of surrounding rock particles increases and the vibration velocity decrea-ses.The dynamic load can cause initial strain energy of surrounding rock to be released,and the strain energy density of the rock decrea-ses.The dynamic damage of surrounding rock always starts near the top of the roadway,and the damage level and areas increase with the increase of the initial stress.