Research On Rigid-flexible Chimeric Bolting-grouting Roadway Supporting Technology In Inclined Seam

With the rapid development of mining technology and Coal machinery, the strength ofcoal exploitation grows more and more strong, which makes reserves of coal owns betterhydrogeological conditions less and less. Coal enterprises in coal mining are gradually turningto the inclined coal seam and deep geological condition complicated coal seam. In China，thelarge dip angle coal seam coal reserves account for about15%~20%of national coal reserves,which is abundant and owns better coal quality and high exploitation value. Therefore, thesignificance of study on stability control of roadway in inclined coal seam mining isparticularly important. This paper, combines with the engineering example of Changgouyucoal mine-410m horizontal crossdrift pass through steeply inclined coal seam carried out thefollowing main research by the methods of theoretical study, similar simulation, numericalsimulation, engineering monitoring.(1) It can be concluded that the reason of deformation and failure of the roadway withlarge inclined angle through the theoretical research： In inclined roadway, because ofasymmetricof its surrounding rock structure and rock properties. Different rock layers of theroadway roof have thin thickness, low strength, low cohesion or even no cohesion betweeneach other and their stratification, joints and crack grow. Because of this, it leads to theasymmetric deformation of the roadway.(2) Grouting simulation test and strength test were carried out on the coal sample takenfrom-410m level of Changgouyu coal mine. By the experiment, the proportion of ingredientsof grouting mixture and grouting parameters can be determined. Analysis about thecompressive strength of test block before and after grouting on coal sample shows that,mechanical characteristics of the testing specimen can be obviously improved after grouting.The cohesive force increases nearly5times than before. Its angle of internal friction is also improved and its compressive strength increases obviously.(3) Simulation were carried out on roadway under different support patterns bynumerical simulation software. And simulation analysis were performed on yield failure range,the vertical stress distribution, distribution of horizontal stress, vertical displacement,horizontal displacement distribution under anchor net spray support and bolt-grouting support.The analysis results show that the difference of deformation include interlaminar shear slipdeformation produced by asymmetric effect of rock mass structure and high stress extrusiondeformation is the cause of the asymmetric deformation of large angle rock roadway. Obtuseangle position of roadway and the tilting direction is the first key part of Deformation andfailure area. The form of bolt grouting support can improve the stress state of the roadwaysurrounding rock, which can make the stress uniform and make use of the bearing capacity ofthe rock itself and surrounding rock supporting effect can be brought into full play. For thisreason, roadway deformation decreases; and the stability of roadway can be controlledeffectivelywhich can achieve the purpose of long-term stability of roadway.(4) The results are applied in-410m level horizontal corssdrift of Changgouyu coalmine. After monitoring and analysis of the roadway’s displacements and the force of bolt andanchor, it is verified that the stability of the roadway support structure satisfy the requirementsof safe production of mine roadway, and it provide a reference for the safe production of deeproadway of steeply inclined coal seam.