Study On Surrounding Rock Control Technology In Hard Roof And Large Mining Heigh Stope

In the process of coal mining, coal seam hard roof is one of the maindisasters in coal mine accident. Hard roof of stope is close distance will lead toa large area of hanging roof, a large area of hanging roof sudden falling impactdynamic pressure, cause harm to the equipment and staff, to bring great hiddentrouble to the safe production of coal mine.In this paper, taking Guanlingshan mine15202hard roof working facewith large mining height as the engineering background, based on the detailedanalysis and summary of existing research results, by means of the analysis ofthe field measurement, theoretical analysis and numerical simulation of hardroof of large mining height mining stope ore characteristics, workingresistance of hydraulic support and support adaptive pressure. The mainresearch results are as follows:The first roof working face with large mining of hard roof weighting stepdistance is41.81m through theoretical analysis and calculation, the periodicweighting step distance is18.46m. Through the numerical simulation of hard roof first weighting step distance of the working face is36m, the periodicweighting step distance is about16m. The comparative analysis shows that thesimulation software to consider the coal and rock in homogeneity andlaboratory determination in coal and rock mass parameters relative to the sceneof the differences, thus leading to the simulated breaking span is relativelysmall. Mechanical analysis shows that the bulk of the immediate roof as hardroof key stratum in fractured and not the overall effect on the bracket. Becauseof itslength, usually located in the rear center support, resulting in broken rockblock rotation. Broken rock break ingrotary motion in the previous broken,falling rock formation in the occlusion of goaf, the formation of the occlusalload friction between rocks reduces the actual need to support. On this basis, tostudy the rock between the occlusal function, working resistance of fac esupport the reasonable calculation. Can be calculated, taking into account thespare coefficient are calculated per meter of resistance of support, support for8283KN/load frame, site selection of ZZ8800/25/50type hydraulic support isreasonable.The rock conditions, based on the analysis of the pillar shaped figure onthe movement rule of overlying strata are studied based on the roof, becausethe alternating stiffness of roof, roof breaking rotary, overlying soft rock stratamovement, with the lower hard rock caving can timely filling mining minedout area, the formation of "three zone". Therefore, Guanling coal15202working face can form "voussoir beam" structure in top layer, to realize the protection of mining coal seam mining space, generally will not cause until thesurface collapse.Through the observation of mine pressure of working face support at theend of cycle time weighted averagere sistance, resistance, setting load isanalyzed. The results show that: the support of15202working face the settingload of utilization is good, can satisfy the working face roof controlrequirements; support in fully mechanized mining face with ZZ8800/25/50, thestatistical work of hydraulic support test was calculated as8664.09KN~8715.37KN, show that the bracket can meet the requirements ofthe roof control. Support to pressure the average resistance, mean maximumresistance, non pressure to pressure the average resistance has the samechanging trend along the working face, the maximum resistance performancefor the central frame, both sides support resistance to both sides. In front of theworking face of coal wall of the overall pressure on the smaller, smaller,15202working face crossheading advanced support length is20m, which can meetthe requirements of production safety work surface.Proposed in view of the Guanling mountain coal15202roof top open offcut deep hole loose blasting technology to increase the hard roof fracture rate,to achieve a certain area collapse in time, reduce the threat of hanging roofpressure area. The blasting scheme, the technical process and the process isdiscussed in this paper.