Research And Applicayion On Supporting Technology Of Fully-mechanized Caving Along Gob Large Span Open-off Cut In Thick Coal Seam

The full-mechanical caving along gob large span length open-off cut in thick seam has own characteristic: the coal pillar along gob has been damages seriously, the span of open-off cut is large, the roof of open-off cut is the coal seam, difficult to support. It has not form the complete supports and protections system at present, and it urgently awaits to research science reasonable supports and protections way to guarantee that its supports and protections is safe and reliable.This dissertation set Baodian colliery as the prototype. Using numerical simulation analysis, similar material simulation experiment, theoretical analysis and scene experience, we do research to rock stability, reasonable coal pillar, roof structure, supporting principle, supporting way and parameters.Discrete element numerical simulation analysis on the rock movement of open-off cut is being done, and we obtain the following conclusion: the size of pillar, supporting way and parameters has great effects on surrounding rock stability. With the pillar size be larger, the stress area that the roadway be located change from low stress area to peak stress area and final be in original rock stress area; with the supporting way be change, the surrounding rock structure is change, when using cable truss, the roof form "pressing reinforced beam"; cable span more bigger, and surrounding rock stability more weaker.It can get some conclusions from the similar material simulation experiment of open-off cut. With working face advancing, the inferior rock of moving rock is forming "space small structure", and superior rock is forming "space large structure"; when "large roof is coming, the basic roof turn into step structure, the pressure and the influence scope is large. When using cable truss, the surrounding rock is steady.Theoretical analysis is being done on reasonable position and supporting way of open-off cut. Supporting pressure is assume "the camelback" distribution, the position and the value of the biggest supporting pressure does not have the sweeping change; after using the cable supporting way, and the loosening rock layer and weakness plane form "carrier beam"; and then hits the anchor cable, thickened bar's thickness correspondingly, moreover it make "extrusion beam" fix to the stable rock layer, it is more effective to control the rock distortion.Thanks to the scene study, we can see that the stability of surrounding rock balance structure has great influence to open-off cut, when using cable truss, the roof forms bend thick plank, and limiting horizontal crack cut through, cable truss supporting way has obtain great technology and economic result.