Study on Once-tunneling Technology for Large Cross Section Open-Off Cut Based on Continuous Mining Construction

In order to improve the driving speed of large section open-off cut and ensure roadway overall stability during tunneling process，the once-tunneling technology suited for continuous miner is proposed，which greatly improves the driving speed. A Midas/ GTS numerical simulation is applied to study the surrounding rock deformation features and the stress distribution features of the open-off cut under two kinds of excavation modes of continuous mining once-tunneling and traditional sub-sectional secondary tunneling. The results show that the roof subsidence value, the floor heave value and the plasticity zone of the surrounding rock are small with continuous mining construction once-tunneling technology，the gateway stress is even and favorable to the stability of the surrounding rock.