Study On Support Technology Of Weak Cemented Soft Rock Roadway In Western China

The weak cemented soft rock is dilated and muddy by water,resulting in large deformation of surrounding rock and failure of supporting structure,which seriously affects safety.Based on the study of Wangwa No.2 coal mine,which is characterized by loose and broken surrounding rock,easy to muddy and hydrolyzed,and serious floor heave deformation,the deformation and failure characteristics and causes of weak cemented soft rock roadway in the lower part of No.21 mining area are systematically analyzed by means of relevant data review,field investigation,theoretical analysis,laboratory test,numerical simulation and field observation Effective support technology.Through XRD,XRF and electron microscope scanning of surrounding rock samples,the composition and microstructure of the surrounding rock of the roadway are obtained.Some physical properties of the surrounding rock of the roadway in the lower part of mining area 21 are analyzed.Through the physical and mechanical properties test of the surrounding rock,the mechanical parameters of the surrounding rock of the roadway are obtained.It is determined that the surrounding rock of the roadway in the lower part of mining area 21 is "weak cemented soft rock" with low strength,poor cementation,easy weathering and easy to be muddy when encountering water " Through grouting materials,the surrounding rock samples of the roadway after "crushing" are grouted and reinforced,and the mechanical properties of the grouted and solid are analyzed.Compared with the physical and mechanical properties of the original rock,the uniaxial compressive strength is increased by 156%～240%;the elastic modulus is increased by 118%～221%;the Poisson’s ratio is increased by 150%～179%;the tensile strength is increased by 316%～426%;the density is reduced by 128%～130%,indicating that the physical and mechanical properties of the surrounding rock after grouting are improved The resistance to deformation and failure is better than that of surrounding rock without grouting.By using FLAC3D software,the mechanical model of roadway support structure is established for different surrounding rocks such as coal,mudstone,fine-grained sandstone and medium grained sandstone.By analyzing the causes of deformation and failure of roadway under the original support scheme,the displacement distribution law of surrounding rocks under different support schemes is obtained,and the deformation characteristics of surrounding rocks under different support schemes under the same conditions are studied.Combined with the site construction conditions,the final decision of 21 mining area lower parking lot is to adopt the combination of grouting reinforcement technology and anchor net+anchor(cable)combined support technology to repair.21 mining area lower parking lot carries on the spot industrial test,through to the spot anchor bolt,the anchor cable dynamometer monitors the mine pressure change,uses the cross method to monitor the roadway surface displacement under the new support plan,compared with the original support condition distortion,the result proves that the stability of the roadway surrounding rock is effectively controlled under the new support plan,saves a lot of manpower and material for the mine To achieve better economic benefits.Figure 62,table 17,references72...