Experimental Research On Mechanical Parameters Of Double-Direction Control Bolt Supported Rock Mass

At present phase,Coal is an important energy demanded in China.The support effects of roadway directly affect the operation of coal mining.The mining way along the gob-side entry retaining will produce great impact pressure on the coal pillar in the parallel roadway,which causes the serious deformation and even complete destruction of the roadway.The system of double controlled bolt through the coal?rock?wall carries on the bidirectional equivalent reinforcement,which makes the mechanical properties more uniform and greatly reduces the deformation and damage caused by the uneven internal stress.By changing the parameters of the bolt,the influence of its mechanical properties on the anchorage composite is discussed.The paper bases on the analysis of theory,the simulation test and the software FLAC^3D of numerical simulation,analyzed the mechanical properties of the various layout parameter of bolt for the medial coal pillar of parallel roadway.The main conclusions are as follows:?1?According to the outcome of the similar material test,the system of double control bolt can strengthen the ultimate strength and residual strength of anchoring complex,especially to residual strength.?2?Numerical simulation shows the failure form of the coal pillar in the roadway and points out the stress state of each part of the coal?rock?column and provides reference for the layout of double-control bolt.?3?FLAC^3D was used to analyze the stress state,plastic zone and displacement of the anchorage composite under different conditions of different densities,different diameters and different preloads.It was shown that the mechanical properties of the anchorage composite were improved with the increase of the three factors.Under the same conditions,the effect of supporting with preload is better.