Research on gob-side entry retaining technology of shed roadway in Donghuantuo Mine
In order to realize the gob-side entry retaining under the condition of traditional shed supporting,the shed roadway of No.20221 working face in Donghuantuo Mine was taken as the research object,and the method of establishing mechanical model was used to calculate the bending moment of coal pillar under different conditions.According to the actual on-site input of relevant values,under the condition of stable overall structure,the length of the cantilever beam outside the arch shall not exceed 6 m,and the overlap length shall not be less than 4.5 m.At this time,the supporting strength met the requirements.The process of gob-side entry retaining in shed roadway was designed,and the engineering effect was analyzed.Affected by the lithology of roadway floor,the deformation of roadway is mainly floor heave and two-side movement,and the roof has almost no subsidence behind the working face.When the measuring point is located in front of the mining face,the average rate of floor heave is 5 mm/d;when located 0-35 m behind the surface,it is in the surge area of the floor heave,with an average ve-locity of 62 mm/d;after a distance of more than 35 meters from the working face,the average speed is 15 mm/d;at present,there is no stable area,and the governance is mainly based on clear lying.The mutation point of the displacement of the two sides is 0,and the mutation value is 280-320 mm.The 0-91 m is in the surge area of the displacement of the two sides,and the average rate is 12.29 mm/d.91-200 m is loca-ted in the two sides of the displacement of the slow increase area,with an average velocity of 2.5 mm/d.When it is greater than 200 m,the ve-locity is less than 1 mm/d.
shed supportinggob-side entry retainingmechanical model