Research On Control Technology And Analysis Of Bolt Breaking Mechanism In Coal Roadway Under Deep And Large Section Condition

With the increase of the depth of coal mining in our country, the stress of the surrounding rock changed dramatically, and one of the most distinguish features is high geo-stress.Under high geo-stress complex conditions, such as breaking the induced anchor supporting structure failure problems appeared gradually, which is serious threat to the economic benefits of coal mine and production safety.In order To solve the deep roadway support bolt broken reality, this paper analyzes the theoretical studies of anchor under complex stress conditions(axial tensile load, transverse shear load, tangential torsional load) of the mechanical characteristics, using numerical simulation the studied rock deformation laws of deep roadway deformation features and bolt, cable and other support structures in supporting conditions, according to bolt material, the breaking strength of the source and location of the broken bolt in the form of classification, deduced tensile load, shear load combined action with bolt axial tensile stress is calculated, based on the new dragon mine site survey results, combined with bolt broken form, we analyzed each bolt broken reason and targeted We propose the use of secondary support, increasing the diameter of the bolt and other control measures, and proposed deep under complex stress bolt broken control program, and the program parameters were optimized. Paper made about the results and conclusions:(1) Bolt withstand axial tensile load of coal, mainly from plastic expansion, expansion and formation separation, anchor withstand lateral shear loads mainly from rock dislocation, anchor withstand the torsional load mainly from the preload application process. Therefore, that anchors subject to axial tensile loads and transverse shear loads are all surrounding rock displacement of the anchor load, anchor withstand tangential torsional load belongs to artificial stress load.(2) deep seam roadway with a large cross section of large deformation, deformation large area, a large plastic zone features, such Bolt, reliable anchor combined support technology lies in "soft after just the first anchor, anchor immediately after the first flexible cable ", using bolt multilevel structure allows the pressure to adapt to surrounding rock deformation characteristics of large capacity and extend its anchor end installation.(3) According to the source anchor breaking force, breaking the bolt into the form of cut, brittle fracture, broken, pull off, crash, back caps, crash six categories; according to bolt material, the bolt broken into the form, etc. strong threaded bolt broken, small pitch high strength bolt broken, broken anchor and other categories; according to bolt broken position, the bolt broken into the form of shoulders, Jianwo, helped by a second root roof, roof middle helped by roof second root portion, with the help of six central and the like.(4) proposed deep complex stress condition bolt broken thought control(raise anchor material load limit or reduce the load anchor actually incurred) and four control program(to increase the size of the bolt, bolt strengthening material, weakening support stiffness, the implementation of secondary support).