Study on law of strata behavior in shallow-buried working face under contiguous gobs

For the same shallow buried working face, there are specific engineering conditions in the gob under the close distance and solid coal rock. The theoretical analysis and field measurement method were used to study the characteristics of the mining pressure under the working face in the very close distance gob. The geological conditions of single working face mining pressure behavior law were compared and analyzed. The results show that under the condition that the equilibrium "masonry beam" structure formed by the overburdened key layer is close to the lower coal seam, the overburden of the working face is more unstable, the pressure is frequent and the pressure strength is higher; Under solid coal and rock, the mean value of the pressure step distance is smaller, the average amplitude of reduction is 19%, and the variation in the direction of the strike is large. There is no obvious regularity and periodicity, and the overall pressure strength increases. The average increase is 6%, and the dynamic load coefficient is reduced. The working area under the gob is more affected than under solid coal rock. The distance between the peak of the supporting pressure and the working surface is nearly the same. The distance between the peak of the supporting pressure and the working surface is basically constant, and the peak strength and the stress value of the stable coal in the deep are obviously reduced. Roof management and mine pressure observation should be strengthened during the mining of the working face under the gob, and corresponding measures should be taken in time to ensure safe production.