1.Mining and Design Branch,China Coal Research Institute,Beijing ,China;2.Department of Mining and Design,Tiande Science and Technology Company Limited,Beijing ,China

In order to study the failure condition of the gateway surrounding rock in the driving process of the large cross section gateway with thick top seam and the rational support method,a numerical simulation and an underground test method were applied to analyze the deformation failure condition of the gateway surrounding rock under different width of the gateway and the different support method affected to the stability of the gateway surrounding rock.The study results showed that the width variation of the gateway would have a big influence to the stability of the thick seam roof.When the width of the gateway was increased from 4 m to 6 m,the roof subsidence would be increased with 55 mm.The max deformation would be occurred in the middle of the thick seam roof.The application of the pre-stressed bolt and anchor support method and a proper improvement of roof support density could make a higher pressure stress to the surrounding rock in the shallow depth and could well control the roof subsidence.The underground engineering practices showed that the rational pretension and the support parameters of the bolt and anchor could keep the stability of the gateway surrounding structure.The mine pressure monitoring and measuring data showed that the max deformation of the two sidewalls both would not be over 40 mm,the max bed separation value of the roof would not be over 100 mm,the bolt and anchor stressed would keep stable and the support effect was excellent.