The Reasonable Bolting Selection And Optimization Of Kouzi East 11-2 Mine Coal Roadway With Composite Roof

With the development of the coal industry, shallow coal mining has been almost depleted; we had to deeper mining to meet people’s daily needs for coal resources. According to the statistics, deep mining of coal resources in most of the mine tunnel are composite roof, If the composite roof instability will cause the occurrence of roof collapse, therefore, to remain the stability of separation between the layer composite roof is the issues that deeper mining should be considered the most. In this paper, combined with Kouzi east 11-2 mine current roadway engineering practice, using the method of theoretical analysis and numerical simulation analysis, the 11-2 coal roadway supporting the rationality of the existing support pattern and parameters analysis, we should choose reasonable support nursing program and the corresponding support parameters, and on this basis to remain the structure of the 11-2 coal roadway roof surface layer determination and the surrounding broken rock loose stable, stand near the ultimate bearing capacity of the stent in the subject.The authors combined with Kouzi east mine 11-2 coal roadway engineering, choose the appropriate model numerical simulation. Numerical simulation model is divided into two:(1) The model on coal seam roadway layout:11-2 advanced driving pedestrian mountain coal, coal seam roadway layout in 11-2, and the tunneling along the roof of coal seam direction to driving, according to the geological histogram to determine the compound roof structure, two coal wall and floor lithology.(2) The model roadway layout in 11-2 coal seam roof:driving late in 11-2 coal seam roof, floor roof of coal roadway driving along the 11-2,the coal between two rock and bottom seam is 11-2.By analyzing the stability of 11-2 mine coal roadway complex roof separation in different support and parameters, based on the two kinds of numerical calculation model,respectively, when the support has or has no preload (bolt pre respectively tightening torque 260N.M, anchor preload 16T), supporting strength are no supporting, bolt support parameters(according to the the provisions of support parameters of bolt anchor cable support), anchor cable support (distance between the anchor cable row and third, respectively, for the next half) under different conditions,the results of the two models were analyzed, and come to the following conclusions:(1)whether the coal roadway is embedded in coal seam roadway or embedded in the roof of roadway, the drum is smaller than two and bottom;and the instability of the roof layer appear is mainly due to structural layer separation(2)Interlayer separation instability is mainly beginning from the key layer, the reasonable support (main anchor cable support) at the same time, should focus on the key layer tightly strengthen support,mainly in addition to choose rational support methods on the key layer can be strengthened, supporting reasonable support parameters support position of key stratum and key layers of interlayer separation stability has great influence, only taken into account, it can maintain the stability of the key layer;(3)For deep mining in coal mines, the central structure of the coal mine roadway roof produce tensile stress, and the stress caused the roof structure plane separation. Therefore, in support of the key should focus on strengthening the central layer surface support, so as to maintain the separation between layers of stability.(4) The roof abscission layer of Kuzi east mine 11-2 coal roadway roof arises because the interlayer separation caused by unstable, but the plastic deformation of roof is stable; 11-2 coal roadway in the actual project, selection of supporting form is the bolt cable combined support form, but according to the analysis of anchor cable supporting density (spacing) is small, the preload is too small, the layout is not reasonable. According to the results of this paper, the anchor cable support parameters are improved:①The anchor cable supporting density from 1.57/m2 (the original roadway bolt spacing is 0.800* 0.800m),3/m2 (into the bolt spacing to 0.600* 0.600m); the bolt half width in the original structure of the cable in roadway density increased to 4/m2 (Anchorage spacing of 0.500* 0.500m), and the other half roadway width from the surface center far within the anchor density should be increased to 2/m2 (Anchorage spacing of 0.500* 0.500m);②The bolt pre tightening torque from the original 260N.m (pre tightening force of about 55.0KN to 340N.m (7) to improve the pre tightening force of about 5.0KN); the anchor pretightening force was increased from 160KN to 200KN.