Study Of The Deformation And Failure Rules Of Surrounding Rock Of Different Depth And Different Section Size Roadways

In the production work of underground mining,it is often used to excavate roadways with different depth,different shapes and different sections according to different production tasks.The deformation and failure of roadway surrounding rock are closely related to the security of underground excavation works.Through the dimensional analysis of the displacement of roadway surrounding rock,it is found that the displacement of roadway surrounding rock is changed regularly with the buried depth or the section size of roadway.And this detailed regular relation is studied by numerical simulation of particle flow code(PFC).Based on the particle flow code,the excavation simulation of the straight-wall-semicircular-arch roadways and square roadways with different depths and section sizes are carried out.For the problem of insufficient displacement accuracy through the history command of PFC,so the code for calculating the precise displacement and output displacement of the surrounding rock is written in the fish language.From the aspects of displacement,stress and energy,the deformation failure characteristic and the regular relation of deformation failure with roadway depth or section size changes of roadway surrounding rock are studied.The following main conclusions were obtained:(1)The deformation and failure of surrounding rock becomes serious with the increase of the depth and section size of the roadway.The straight wall and semicircle arch connection position,the lower part of roadway sides and the bottom corner surrounding rock of straight-wall-semicircle-arch roadway is caved and broken more.The surrounding rock of roadway sides of square roadway is bulged and caved more.The deformation and failure of the surrounding rock in diagonal position of square roadway are more.(2)When the section size of roadway is constant,the vertical displacement of surrounding rock at the top,bottom and top corner of roadway has a good linear relationship with the buried depth.Within a certain depth range,the vertical displacement of surrounding rock at the bottom corner and sides of roadway has linear relationship with the depth.The linear relation between horizontal displacement and buried depth of roadway surrounding rock is not obvious.(3)When the depth of roadway is constant,the vertical displacement of surrounding rock at the top and bottom of the straight-wall-semicircle-arch roadway and square roadway has a good linear relationship with the roadway size(width and length of the roadway).At the 450 position of the semicircle arch of the straight-wall-semicircle-arch roadway,the vertical displacement of the surrounding rock also has a good linear relationship.(4)The vertical stress of the surrounding rock of the roadway sides is the largest.The horizontal stress in the bottom corner of the straight-wall-semicircle-arch roadway is the largest.The horizontal stress in the top corner and bottom corner of the square roadway is the largest.When the lateral pressure coefficient is constant,the vertical stress and horizontal stress of surrounding rock of roadway has a good linear relationship with the buried depth.(5)The energy development of surrounding rock caused by excavation of roadway is divided into three stages:energy release,energy recovery and energy stability.The energy changing value of numerical models have a quadratic function fitting relationship with roadway buried depth.And there is a linear relationship between the energy changing value of numerical models and roadways section size.