The Stability Classification Of Deep Coal Roadwayroof And The Study Of Control Strategies In Chengjiao Coal Mine

At Chengjiao Coal Mine, the mining activity goes deeper. The mining depth are gradually largened with larger ground pressure. Because of the influence of geological and environmental changes in the process of coal, the lithology and rock stratum structure of coal seam roof rock strata change frequently in same layer of the same tunnel, and leading to the strength 、 roof thickness and relative position of composition of roof often change greatly. Excavating a tunnel will encount a variety types of roof. Using a kind of support parameter will let the support strength is too large In some areas, resulting in the waste of resources, or it is not enough, existing Security risks of roof fall in the roof support. The two results are not desirable. According to the analysis and research of all geological characteristics of deep coal roadway roof in Chengjiao Coal Mine, the paper classifies the deep coal roadway roof stability, choosing a reasonable supporting scheme. The paper obtains the following results:First of all, analysising the overall geological structure and the deep coal roadway roof structure of Chengjiao Coal Mine. Obtaining the main influencing factors of deep coal roadway roof stability, it includes the roof rock difference, strata combination mode, cement type, The development degree and type of bedding(fault). And founding the key rock beam bearing structure of coal roadway roof plays a decisive role on the stability of coal roadway roof.Secondly, through the analysis of the deep coal roadway roof surrounding rock stress, the determination results of physical and mechanical properties of coal or rock and the roadway of coal seam occurrence histogram, determining the steady rock limit span index, the stability of roadway roof strata from the distance and the roof unsafety factor is the three classification index.Third, by determining the five typical roadway roof classification index level, finishing the combination of roof stability classification, the roof stability of deep coal roadway of Chengjiao Coal Mine is divided into five levels: very difficult to support type, hard supporting type, medium difficulty type, easily supportingtype and easy type support.Fourth, for the four or five level roof type, forwarding the echelon support technology principle, analysising the formation and mechanism of the echelon strengthening bearing beam structure,getting the key technology of deep coal roadway roof stability control in Chengjiao Coal Mine. Using "four high" performance bolt, high preload pressure cable and anchor beam Maintain the stability of roadway.Fifth, 21105 lane roadway start construction in 2014 April, after two months of construction site, completing 450 m test road construction task. After the roadway surface displacement observation about nearly a year, we find the maximum amount of roadway surface displacement occurred in the 747 m, the left maximum deformation amount is 57 mm, the right maximum deformation amount is 59 mm, the roadway roof maximum deformation amount is 61 mm. The roadway roof is ont separation before 12 days, but it began to appear roof separation after 12 days. The separation occurs outside the scope of the anchor, the maximum separation volume is 7mm. The whole roadway supporting is well.