Sturdy on ground pressure law and support adaptability of deep-buried and ultra-long fully-mechanized longwall mining face

In order to explore the laws of ground pressure and the adaptability of hydraulic supports in the deep-buried and ultra-long fully-mechanized mining face in the Mongolia-Shaanxi area,the No.21102 first mining face of Hulusu Coal Mine was used as the engineering research background,and the theoretical calculation of ground pressure,the on-site dynamic real-time monitoring and KJ21 software analysis of a variety of means such as working resistance of hydraulic support,the periodic pressure on the working face and the change law of abutment pressure were analyzed.The results show that the initial pressure step distance of No.21102 working face roof in Hulusu Coal Mine is 38.5～45.9 m,with an average of 41.4 m,which is basically consistent with the theoretical calculation.The maximum step distance of periodic pressure is 31.9 m,the minimum step distance of cycle pressure is 12 m,and the average step distance of cycle pressure is 22 m.When the basic top pressure is applied,the maximum dynamic load coefficient is 1.09,the minimum is 1.03,and the average is 1.06.The dynamic load coefficient is very small,indicating that the overall pressure on the working face is not obvious.The pressure of the hydraulic support is divided into five areas along the working face:“low pressure area,high pressure area,low pressure area,high pressure area and low pressure area”,which are distributed in the shape of a “saddle”.In the direction of the working face,the pressure can be divided into three areas:“low pressure area,transition area and high pressure area”.The influence range of the advanced abutment pressure of the working face is about 45 m in front of the working face,and the significant influence range is about 18 m in front of the working face.The current leading support distance of 20 m meets the requirements.It is in the early stage of ensuring the quality of the bolt support of the mining roadway and the quality of the single pillar support.The existing four rows of advanced support single pillars can be reduced to two rows.Judging from the use of the ZY10000-16/32 two-pillar shielded hydraulic support in the No.21102 working face,the support working resistance is relatively small.It is recommended that hydraulic supports with a working resistance of 12 000 to 14 000 kN should be selected for fully-mechanized coal mining faces with similar coal seam conditions in the Inner Mongolia and Shaanxi regions to prevent large-area pressure caused by large roof pressures during the stop of production,passing through empty roadways and crossing faults.