Analysis On Different Support Forms Of Roadways In The Deep Mining Of Jinchuan

In China,the depth of mining is increasing every year,but with the increase of mining depth,the ground stress also increases,and the underground roadways are easily deformed or even damaged directly,which seriously affects the safety and efficiency of underground constructions.Therefore,studying the characteristics of surrounding rocks and controlling the stabilization of supports of deep mine roadways are of great significance for safe and efficient mining of deep mines.In this paper,the underground tunnel of copper and nickel mine in Gansu Jinchuan mining area is taken as the research object.Through studying the roadway supporting body in the deep mining area with deformation and damage,the factors affecting the deformation of the roadway,the failure characteristics,the deformation mechanism and the supporting materials and ways of the roadway are explored.The experience of deep mining roadway is summarized,and the effectiveness of different supporting methods is compared,and the most secure and most suitable supporting method for site construction is studied.The following conclusions are drawn:(1)on the basis of the surrounding rock control principle of the soft rock roadway with high strain capacity and the interaction mechanism between the supporting body and surrounding rock,the support method with multi arch coupling with inverted arch,straight wall,semi-circular arch + high strength anchor + anchor net + shotcrete is adopted.Through the bottom plate and long anchor cable,the main parts of the deep roadway are strengthened to improve the stability of the deep roadway.(2)regarding the deformation and speed of the roadway under the original support scheme,the optimum coupling time of the long anchor cable is determined as follows : after the excavation of the bolting support,the anchor support is lagged behind for 2.3 days,and the connection between the anchor cable and surrounding rock is realized thoroughly in time.Through the engineering practice optimization,the size of the long anchor plate is determined to be 80 x 80 x 20 mm,200 x 200 x20 mm.The long anchor cable and surrounding rock meet the pressure requirements in space.(3)By virtue of the research on both deep mining engineering and backfilling system engineering,it is proposed that effective support can not rely on a single support way.Starting from the rigidity and strength of the anchor and long anchor cable,the anchor net cable connection support method can be used to maximize the interaction between the surrounding rock and the anchorage structure.It is determined that the roadway section of deep mining in Jinchuan is 4.8-3.8 meters.From the mechanical analysis,it is determined that the maximum bending moment of the inverted arch decreases first and then increases with the increase of the height of the reverse arch,and thus the support method of the inverted arch road + long anchor cable is found to be beneficial to maintain the stability of the roadway.(4)Through the repair of the 50 m section of the 1000 m level along the 1#Transportation Road(1# fork 2# fork)in the No.2 mining area of Iinchuan,the paper compares and analyzes the support effect between the 36#U steel arch and the concrete-filled steel tube,and puts forward the concrete pipe beam supporting technology in the mining area(Fills the concrete in the steel pipe,so that the steel tube confined concrete and concrete can avoid or delay the buckling of the steel pipe).It is proved that the concrete steel tube beam support can greatly improve the strength and plasticity of the support,and improve the impact resistance and earthquake resistance.