Study on factors affected to stability of gateway with thick-hard roof and strong sidewall support

In order to improve the driving efficiency with the rational designed support method of thick and hard roof gateway, with the air return gateway of No. 15 seam coal mining face under thick and hard K2 limestone roof in Jincheng Mining Area as an example, a numerical calculation method was applied to the study on main factors affected to stability of hard roof gateway and support technology. The result showed that the hardness and thickness of hard roof increased, the roof deformation and plastic distribution scope of the gateway would be steadily decreased. With the support strength of two sidewalls increased, the deformation and plastic distribution scope of the two sidewalls would be obviously decreased and the roof deformation would be reduced in a certain degree. Under the second redistribution role of the mining influenced stress, the ultra thick and hard roof would always be in an elastic status, there was no pressure released zone and the support would have a less influence to the deformation of the roof and surrounding rock. Under the non support of the roof, the strong sidewall support plan could effectively control the stability of the thick and hard roof gateway.