Study On The Technology Of Phased Gob-side Entry Retaining In Thick Coal Seam

In order to solve the gas exceeding limit of the upper corner of the mine with coal and gas outburst.Combining with the production geological conditions of Huarun Daning Mine in Shanxi Province,this paper puts forward the technical idea of phased gob-side entry retaining by filling roadside with high-water material.And implementing shifting Y-type ventilation in working face.In order to ensure the stability of surrounding rock of gob-side retaining roadway,through theoretical calculation,numerical simulation and field practice,the movement law of overlying strata,stability mechanism and control technology of surrounding rock in phased gob-side retaining roadway with large mining height are studied,and the following conclusions are drawn.?1?Based on the theory of key strata put forward by academician Qian Minggao and combined with the production geological conditions of the test mine,the position and periodic breakage form of key strata in the overlying strata of the phased gob-side retaining roadway are analyzed.It is concluded that the small periodic weighting of key stratum I has little effect on the deformation of surrounding rock of roadway,and the large periodic weighting of key stratum II has great influence on the deformation of surrounding rock of roadway.Key stratum II is the main control stratum of phased gob-side entry retaining.It provides a theoretical basis for similar mines to implement phased gob-side entry retaining to determine reasonable spacing of contact roadways.?2?The mechanical model of the composite bearing structure is established,and the formulas for calculating the support resistance of the filling body near the roadway at the initial and later stages of retaining roadway are obtained.And the mechanism of anti-horizontal slip of filling body is also analyzed.Through theoretical deduction,the upper limit formula of retaining roadway width and the lower limit formulas for calculating the width of filling body beside roadway is obtained.?3?By using FLAC^3D numerical simulation software,the stress distribution and deformation of surrounding rock in phased gob-side entry retaining are studied and analyzed.The results show that the stress above the filling body reaches its maximum at about 60 meters behind the working face,and the deformation velocity of the surrounding rock of the roadway reaches its peak at the same position.In order to prevent the deformation of surrounding rock of roadway from being too large to control,phased gob-side entry retaining should be completed before the peak stress of surrounding rock reaches.?4?In view of the three weak links of surrounding rock control,according to the principle of surrounding rock control of"roof control and strong slope",the paper proposes to use high-strength and high-prestressing bolt to support the roof of roadway,and to arrange cable-stayed anchor at shoulder angle,and to use high-strength and high-prestressing concessional bolt to support the side,and to use single hydraulic prop to strengthen the support during the period of mining high stress.