Research On Top Coal Weakening Technology Using High Level Fully-mechanized Cavingin Steep Thick Seam

The steep seam occurrence conditions are complex, in process of full-mechnizied caving,the stability control of coal and strata is critical to safety. This aritical bases on the tunnelstability control during steep caving mining in full-mechnizied process of steep thick seam inUrumqi, using theoretical analysis, simulation, numerical simulation experiment, fieldmonitoring and engineering practice, the stability control technology in these seam is in-depthstudyed.Based on the comprehensive research and analysis of field engineering geology andmining model, a large three-dimensional physical simulation experiment is used to explorethe acoustic emission(AE)row when the surrounding rock breaking and evolution in theprogress of roadway driving, ming, caving and roof picking, mining, which is also revealingthe roadway's characteristic and law from micro-bred, rupture, origin, evolution until macro,crack. Within three-dimensional finite difference calculation program(FLAC3D)to analysiythe roadway's stress and diaplacement character of B1+2 workface on +618 level in XIAO–hongou coal mine, the results show that after the face advancing, aroud the maximumprincipal stress area in the roadway forms great tensile stress area, above the top of the tunnelhave obvious compressive stress, the stress next to two low-corners of roadway concentratesmore obviously, and it presents a significant non-symmetrical features. After anchor controlmeasures is taken, roadway surrounding rock mass's displacement volume decrease, tensilestress area has been significantly reduced, and the stress concentration area concentratedaround to the roadway. The thickness of the ring bemoces smaller, and non-continuous, all ofthese shows that the bolting system can effectively control the surrounding rock deformation,and constrained the roadway of displacement, it has played a significant role to the roadstability control. The support of bolt - metal mesh - h-shaped steel belt and chains models and parameters is optimizated and assured. Using loose circle and drilling peeping to monitor andverify support result. Practice shows that the solution meets the needs of onsite securityproduction.This study can provides significance to other similar roadway strata stability control.h...