Stability Analysis Of Surrounding Rock In Deep Roadway Under Complex Stress Field

With increasing burnout of shallow resources,deep exploiting has become the focus of current research emphasis,but deep resource mining is also facing many problems to be solved,such as layer crack,rock burst,large deflection and other issues pose a great threat to the safe production of the mine.In order to study the impacts of deep,complex stress fields on the stability of tunnel wall rock during stepwise excavation of tunnels,the deformation mechanism of deep roadway was analyzing.Based on the measured data of Yangquan No.2 Mine,the corresponding model was established in FLAC3 D software.The control variable method was adopted,and modifying stress in X and Y steer respectively.The step by step excavation analysis of the model was performed,and the regularity of the evolution of the principal stress difference,increment shear deformation and plastic zone of roadway in different stress fields was investigated.The main research topics are as followings:(1)Study of the stability of roadway surrounding rock under different maximum horizontal principal stress.Research and discover that the stability of roadway deep surrounding rock from big to small is sorted as two ribs,floor,roof;the influence degree on the stability of tunnel wall rock from big to small is ranked as floor,roof and two ribs;the main stress difference of deep country rock floor and roof increases,decrease and grows when the maximum horizontal main stress,also with growth of maximum horizontal main stress differential of deep surrounding rock of two rids becomes less.The increment shear strain of roof and shallow surrounding rock of two rib increases with the increase of the maximum horizontal major stress,and the plastic zone distribution of surrounding rock is almost done not influenced by the maximum horizontal major stress.(2)Study of the stability of the gallery around the rock under different minimum horizontal main constraints.It is found that the main stress difference of roof surrounding rock is not affected by the minimum horizontal major stress.The main stress difference of deep surrounding rock of two ribs decreases with the increase of the minimum horizontal major stress,and the main stress difference of shallow surrounding rock of bottom plate increases following with the increase of the minimum horizontal major stress.The influence degree on an increment shear strain of surrounding rock from large to small is the roof,two ribs and floor,and the deformation damage degree of shallow surrounding rock from large to small is two ribs,roof and floor.(3)Study of the stability of roadway surrounding rock under same lateral pressure coefficient.Study of the road surface surrounding the rock was investigated using various lateral pressure coefficients.It was remarked that the affected of excavation of the surrounding rock pavement inside the range of 5 m collision beach of the pavement is large.The principal stress difference between the floor and roof around rock starts to rise with the number of excavation steps and then falls quickly to a steady present trend.With the increase excavation steps,the principal stress difference between the two sides of surrounding rock shows a trend of slow increase,increase rapidly,and gradually rise a stable value.(4)Study of the stability of roadway surrounding rock under different lateral pressure coefficient.Research and discover,with the lateral pressure coefficient rise,the degree of influence on the deformation damage of surrounding rock is sorted from big to small as roof,floor and two ribs.The plastic zone area and shear failure area of surrounding rock decrease and increase.