大采高工作面覆岩运动与煤壁片帮规律OA北大核心CSTPCD

In order to explore the strata movement law and rib spalling mechanism of large mining height working face,three UDEC numerical models under different mining heights were established.The effects of mining height and support panel position on roof caving step distance,shape and rib spalling were analyzed,and the mechanical model of rib spalling was established.The results show that the first weighting step distance is less affected by the mining height,both of which are 45 m.The periodic weighting step distance decreases with the increase of mining height.The roof of the large mining height working face is easy to form a cantilever beam structure because the caving gangue cannot fill the goaf.The increase of mining height will increase the risk of rib spalling.The maximum roof pressure that the rib of the large mining height working face can withstand is calculated,and the criterion of rib slip failure is given.By establishing the numerical model of different positions of the guard plate,the optimal support position of the guard plate of the 8.8 m large mining height working face is obtained.The rib control method of increasing the horizontal thrust and support area of the guard plate is proposed,and the stability of the rib is effectively improved after field application.