Research On The Carrying Capacity Of U-steel Support And Reinforcing Methods In The Three-center Arch Roadway

Along with the increase of excavation depth,the supporting of roadway surrounding rock pressure is growing on the mining structure,high stress soft rock roadways support become the key and difficult problem to be solved urgently.U-shape support become one of the main supporting method of deep soft rock due to having the advantages of high initial yielding supporting force,high tensile compressive strength,high utilization rate of cross section,and a certain yielding to tunnel excavation.But in engineering practice,U-shape support buckling often failured because of the uneven force,posed a serious impact on the normal use of roadway.For some serious deformation of roadway,the safe production is even threatened,it is of great economic significance to adopt scientific and effective repair reinforcement method to consolidate the roadway,to restore the normal use and safety in production of roadway.In this paper,it took the III1012 roadway driving along goaf of Haizi coal mine as the research background,introduced the theory of soft rock tunnel supporting,and the Haizi ?1012 wind workface failure mechanism was analyzed according to the complex geological conditions of Haizi coal mine,the U-shape set+ tent leg reinforcing anchor combined support was provided,combined supporting structure is the combination of active support and passive support,which can effectively improve the anchor tensile force,the bolt and the interaction between the metallic frame was formed to promote mutually reinforcing mechanism,give full play to the overall carrying capacity of the supporting structure.In this paper,the numerical method was used to solve the support inside and outside edge stress before and after reinforcement,and on the basis of that the before reinforcing near the tent leg arc radius and reinforcing the tent leg of bolt support position was calculated and optimized,combining with the observation before and after the reinforcement calculation of roadway deformation speed,to test the effectiveness of repair reinforcement means,some reference and experience about the researches on unstability of the deformation of deep soft rock tunnel excavation management was provided for our country.