Study On The Rules Of Ground-pressure Manifestation Of And Long Coalface With The Large Height In Sihe Coal Mine

With the increasement of coalface length becoming another main technology for mines to acquire high production and high efficiency of the centralized production, numerous mines in China try to aggrandize the length of coalface. Currently, the coalface length of sihe mine of Jincheng Coal Mining Group has been 300m, along with this trend, it has become an urgent problem to be solved to research into regulations of coal-pressure manifestation of the overlength coalface and the regulations of migration of the overlying rock.This paper has 4301 initial mining fully mechanized working face of NO.4 panel in the east in sihe mine as its engineering background, with the combinative measures of site ground pressure monitoring, theoretical analysis, equivalent material simulating and numerical simulation, this paper deals with the study of the regulations of coal-pressure manifestation of 300m coalface in sihe coal mine which is under the condition of high mining height and deep burial depth, as well as the structure of the overlying rock strata and its movement characters.By means of site ground pressure monitoring and analysis of the regulations of coal-pressure manifestation of the working face, it turns out that the coal roof weighting step has been shorter and the weighting strength has been more moderate when the length of working face of sihe mine changes from former 225m to 300m, and it also finds that 300m working face has enlarged its advanced influenced range and the hysteretic coal-pressure is obvious; working resistance of the support mainly distributed between 6000KN and 9000KN,and the roof pressure presents to be higher in the middle and lower in both ends along the direction where the working face is leaning to, and the pressure is much higher in the tail part than the head part.By analysing the structure of the roof through the means of theoretical analysis using"key stratum theory",analog simulation,numerical simulation, it turns out that when the length of working face increases, the height of the roof breaking will also increase. as a consequence, the 7.1m high layer of medium grained sand in the roof rock and its Control strata has been in the range of caving zone, and 22.93m above the roof rock is the caving zone, and 64.45m above the caving zone belongs to the fissure zone, and above the fissure zone, it has entered into the bending sink zone.