Analysis on the superposition effect of stress and the failure law of surrounding rock during the last mining period of pre-excavation return channel
Article
Figures
Metrics
Preview PDF
Reference
Related
Cited by
Materials
Abstract:
In order to obtain the control method of the pre-excavation return channel surrounding rock failure in the last mining, the superposition effect of the concentrated stress around the return channel and the mining supporting pressure, and the law of surrounding rock failure were analyzed through numerical simulation, and the field verification was carried out. The results show that with the decrease of the distance between the working face and the return channel, the superimposed stress increases gradually and is transferred to the positive side of the return channel, and the failure of the return channel moves from the front side to the working face. Because of the stress superposition effect, when the working face is 20 m away from the return channel, the plastic failure of roof changes from sparse failure to dense failure. Before the failure of coal pillar between the working face and the return channel, the deformation and failure of the back channel mainly occurr at the front side of the return channel. The damage of the front side is more serious than that of the auxiliary side when the coal pillar is less than 5 m. When the coal pillars are completely destroyed, the roof lost support, resulting in roof rotation, and the scope of the roof and floor damage increases correspondingly. It is suggested that the key to control the large deformation of the return channel is to control the stability of the front side of the return channel.
