| The stability control of deep broken surrounding rock roadway under the action of " high stress " has always been a major engineering problem affecting the safe and efficient coal mining in China.This kind of roadway often shows the characteristics of roof plate easy to mesh and leak,two sides easy to shrink,serious floor heave and so on,and the overall deformation is large,the deformation speed is fast,the rheological time is long and so on.This kind of roadway often has the disadvantageous situation,such as repeated renovation and even failure,which not only seriously affects the roadway construction speed and mine production efficiency,but also greatly increases the roadway support cost.Therefore,in this paper,numerical simulation,theoretical analysis and field measurement are used to study the combined support technology of "strong anchor cable + anchor grouting",and has achieved the following main results:(1)A comprehensive geological and mechanical test was carried out on the West transportation roadway: the surrounding rock strength of the roadway is generally low,the integrity of the rock stratum is poor,and the in-situ stress field belongs to the area of medium high to high stress value in quantity;the deformation and failure characteristics and causes of the surrounding rock of the West transportation roadway are analyzed and summarized;at the same time,the shortage of the original support of the West transportation roadway is objectively analyzed and evaluated.(2)Based on the elastic-plastic theory and considering the dilatancy of rock mass in fracture zone,the mechanical model of roadway with broken surrounding rock before and after grouting is established.The analytical solutions of stress,deformation and fracture of surrounding rock and radius closure of plastic zone are obtained.The feasibility of grouting reinforcement technology to control the expansion and deformation of surrounding rock fracture zone is revealed theoretically.(3)Based on the deformation and instability characteristics of the West transportation roadway in the second mining area of xiaohuigou coal mine,this paper puts forward the combined support technology of "strong anchor cable + anchor grouting",expounds its supporting characteristics and principles.(4)With the help of numerical simulation software FLAC3 D,the grouting hole depth,which is the key parameter of grouting,is analyzed and studied.The simulation results show that the deformation of roadway surrounding rock increases with the increase of slurry water cement ratio,and changes abruptly when the slurry water cement ratio is 0.8,decreases with the increase of fracturing grouting area depth,and changes abruptly when the depth of fracturing grouting area is 4 m;the plastic zone distribution range of roadway surrounding rock is small when the slurry water cement ratio is less than 0.8 Therefore,it is suggested that the water cement ratio of slurry should be controlled at about 0.8 and the depth of splitting grouting area should be controlled at about 4m in practical engineering.(5)The combined support technology of "strong anchor cable + bolt grouting" was tested in xiaohuigou Coal Mine West transportation roadway,and the grouting construction technology and key points were optimized.The results of mine pressure monitoring showed that:(1)the displacement of the roof and floor and two sides of the roadway increased gradually with time and then tended to be stable,and the deformation of each measuring point on the roadway surface was allowed to change in the engineering design The results show that the combined support technology of "strong anchor cable + bolt grouting" has successfully solved the problem of reinforcement and repair of the West transportation roadway;(2)the monitoring results of displacement measuring points of deep surrounding rock and grouting effect of broken surrounding rock show that the supporting effect of the whole roadway is good,and there is no obvious large separation phenomenon;the grouting reinforcement effect of surrounding rock in fracture zone is obvious,and the overall grouting reinforcement scheme support and The repair effect is ideal.There are 45 figures,12 tables,and 72 references in the paper. |
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