Study on surrounding rock control of large cross-section open-off cut in short-wall fully mechanized top-coal caving of extra-thick coal seam
Taking the short-wall fully-mechanized caving face of extra-thick coal seam in Nanyangpo Mine of Shanyin Jinyang as the research object,aiming at the support design of fully-mechanized enlarged section cut with a span of 8.7 m,it is necessary to meet the requirements of effective control of surrounding rock deformation of cut roadway,and to minimize the waste of support materials and the high cost of support.The numerical simulation software FLAC3D was used to study the distribution characteristics of roof prestress field under different support schemes,and the support form of large-span cut was determined as the combined support form of bolt,metal diamond net,anchor cable+W steel belt and single pillar.By checking the support parameters,the support design can meet the requirements.Finally,the deformation of surrounding rock was observed on site.The separation values of shallow and deep base points were 9 mm and 12 mm respectively.The subsidence of roadway roof was about 140 mm.The deformation of roadway on coal wall side was about 105 mm.The deformation of roadway on old pond side was about 98 mm,and the deformation of surrounding rock was small.It showed that the large section open-off cut roadway had been effectively controlled,which could meet the requirements of safe production and use,and provided a reference for the support of large section open-off cut under other similar engineering conditions.
large cross-section open-off cutnumerical simulationtheoretical calculationroof controlfield measurement
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