Support Technology Research On Bolt With High Pre-tightening Large Deformation Of Soft Rock Roadway

In order to realize the high-efficiency and safe exploitation in soft rock roadway, and solve the problems about large deformation, high repair rate and high cost of supporting works in the exploitation process of soft rock roadway, therefore, based on the Jinyang mine engineering, the dissertation researches on the geological conditions of the mining area and makes systematic analysis about soft rock through drilling detection, and eventually develops a large deformation bolt (cable) with high pre-tightening force which is suitable for soft rock roadway and has a good effect on surrounding rock deformation control. The research of this paper and development of new products have great significance to guide the application of large deformation bolt (cable) with high pre-tightening force in soft rock roadway. The main research results are as follows:(1) Find out the maximum flexible range of soft rock roadway in Jinyang coal mine is 2.6m, and the average value can reach about 2.1m. And utilizing numerical simulation, the paper concluded that the preload of bolt plays a key role in the deformation of roadway. And for Jinyang coal mine, the appropriate row and column spacing is 900*900mm, and the bolt pre-tightening force is 120kN.(2) Develops a sort of large deformation bolt (cable) with high pre-tightening force, this product can provide high pre-tightening force with no less than 100kN, slip point pressure 180-240kN, and the deformation generally maintain 150-1000mm. The rupture stress of bolt can reach 350kN and bolt maintains a constant or increasing high resistance in the process of deformation.(3) Making numerical simulation about the large deformation bolt with high pre-tightening force through FLAC3D software, and making secondary development to establish axial tensile mechanical model of anchor rod body, in order to accurately simulate the axial tensile mechanical behavior of large deformation bolt.(4) Based on Jinyang Coal Mine, propose corresponding design scheme, and and make comparison between design scheme and original supporting scheme through numerical calculation method. Meanwhile, it is found that, according to field monitoring, utilizing large deformation bolt with high pre-tightening force in the soft rock roadway can effectively control surrounding rock deformation of roadway, which clearly verify the applications of large deformation anchor bolt (cable) with high pre-tightening force.