Study On The Key Technologies Of Gob-side Gate Entry Driving On Deep Working Face

Based on the wider and wider application of high production and efficiency gob-side gate entry driving technology and, the new manifesting rules of the mine pressure and phenomenon of dynamical disasters on deep working face, the subject of studying on the key technologies of gob-side gate entry driving on deep working face is proposed.Firstly, the critical depth of deep mine in Xinwen Mining Area is calculated. The evolution, the distribution rules of abutment pressure and the characteristics of "S" letter type overlying strata spatial structure on gob-side working face are analyzed. And the formation of "plate-shell" big structures, "articulated rock plates half-arch" small structures and their relationship with internal-external stress fields are researched. Then the simulating software FLAC^3D is used to studying the movement of overlying strata spatial structures and the distribution evolutionary rules on gob-side working face and gate entry.Secondly, the necessity of the coexistence of internal-external stress fields on deep working face is discriminated. Based on proposing "two fields with four regions" theory on deep and high stress working face, lateral stress distribution rules are obtained. Then the elastic-plastic softening model is built, the deformed mechanical mechanism and related parameters of every region of gob-side coal mass are researched. By definition the concept of ideal crushing region, the calculation formula for scope of it around the rectangular gate entry after the upper working face mining is derivated. Then a new design method of fully plastic section coal pillar parameters is proposed and the theoretical calculation formula also be given, with which can obtain that the reasonable width of the pillar of tail gate 51103 in Liangzhuang Coal Mine is 5 meters.Thirdly, the influencing factors and the key influencing factors of gob-side gate entry surrounding rock stability are researched. And the distortion and failure character of gob-side gate entry on deep working face is analyzed. After studying on the stability of the big and the small overlying strata spatial structures of gob-side gate entry on deep working face, the instability mechanism for surrounding rock of the entry is investigated, the theoretical foundation for surrounding rock control of the entry is obtained, and the countermeasures and methods for surrounding rock control of the entry are proposed. Besides those, it is pointed out that the instability of the orthotopic big overlying strata spatial structures is the incentive induced factor for gob-side gate entry rock burst in deep mines. Then the controlling ways of the rock burst are given.Eventually, according to geological engineering condition of tail gate 51103 in Liangzhuang Coal Mine, the holistic supporting scheme of full screw threads and equal strength bolt with anchor cable, steel beam and anchor aging steel strip of the entry's roof and sides is put forward. Then, the section shape and sizes of the entry, the bolt supportting ways of entry's roof and sides and, cable strengthening manners of the roof are designed. It is indicated that the supporting scheme and reinforcement measures are reasonable through the field observations of application effect, which can effective improve the rock conditions of the entry, inhibit the loosening deformation of surrounding rock and increase the stability of the entry and utilization ratio of the cross section.