Study On The Stability Of Roadway Surrounding Rock Containing Layered Clastic Rock And Fault Structure In Southwestern Guizhou

Southwestern Guizhou is an important gold distribution area in China,known as the "Golden State of China".The orebodies in this area generally take fine clastic rock as surrounding rock and ore bearing rock,and the stability of mining roadway is greatly affected by layered clastic rock and fault.The study on the stability of roadway surrounding rock with stratified clastic rock and fault structure in southwest Guizhou is carried out to provide support basis for roadway with stratified clastic rock and fault structure.(1)Jin Feng gold mine roadway surrounding rock broken,joint fissure development,roadway in in-situ stress and mining factors such as stress,lack of support strength,deformation and failure of surrounding rock of roadway in a variety of forms,roadway roof and two for rock bolt anchor cable and the coupling effect is poor,anchor rod anchor invalidation,roof and two serious help surround rock mass deformation and destruction.(2)The mechanical model of layered roadway roof beam is established,the stress state of layered roadway roof rock mass is analyzed,and the influence of clastic rock thickness and elastic modulus on the stability of roadway surrounding rock mass is studied.When the roadway width is constant,the larger the elastic modulus E is,the smaller the tensile stress is.The greater the thickness H of roof rock,the higher the stability of surrounding rock.The clastic rock thickness and elastic modulus are the influencing factors of the stability of surrounding rock.(3)A similar experimental model of roadway containing layered clastic rock and fault structure is made,and the mechanical failure experiment is conducted.The results show that the bearing capacity of roadway increases with the increase of bed thickness and decreases with the increase of fault dip Angle,and the fault weakens the overall strength of roadway surrounding rock.The rock mass around the roadway is prone to appear micro-cracks at the interface of layered clastic rock and fault fracture zone.The strain fluctuation range of the roadway roof and the two-sided rock mass is larger than that of the floor.The roof of the roadway near the fault zone falls seriously,and the two-sided rock mass is the most severely deformed and damaged by extrusion to the roadway fronting surface.(4)The influence of the thickness of stratified clastic strata and the dip Angle of fault on the stability of roadway surrounding rock was studied by numerical test.With the increase of the thickness of clastic strata,the volume proportion of the whole weak structural plane of rock mass is reduced and the bearing capacity of roadway is increased.,the influence range of the fault on the surrounding rock mass is larger,and the deformation and damage of the surrounding rock mass on the hanging wall of the fault are more serious than that on the footwall.With the increase of fault dip Angle,the stress concentration area in front of the roadway shifts to the rock mass deep in the roof of the roadway.The larger the fault dip Angle is,the weaker the bearing capacity of the rock mass around the roadway will be,and the smaller the ultimate load will be when the model is destroyed,which is consistent with the results of physical experiments.(5)In order to determine the reasonable support design,the mechanical parameters of bolt support were deduced and the roadway support scheme was designed.For the surrounding rock mass and fault fracture zone,the grouting reinforcement is carried out first,and then the combined support measures of bolt +anchor net + shotcrete are carried out.After adopting the combined support measures,the deformation and damage degree of the surrounding rock mass is small,and the problem of difficult support of the roadway is well solved.