Study on the law of roof breakage and mine pressure passing large cross-section gob group in the fully-mechanized face with high mining height

In order to solve the problem of roof fall when passing through large section gob groups in the fully-mechanized working face with large mining height and avoid the problems of roof falling， the 26 roadway groups in No.22311 comprehensive mining face of Halagou coal mine are taken as the research object.Numerical simulation and on-site monitoring methods were used to study the instability mechanism of gob and the basic law of roof breaking when passing through the gob groups in the fully mechanized working face.The supporting effect of pumping pillar is adopted when passing through the gob of the fully mechanized coal face， and the roof subsidence and pressure are monitored by instruments.Finally，No.22311 fully-mechanized mining face passes 26 large section gob groups safely and smoothly.The research shows that the instability of the roadway is mainly caused by the advance breaking of the basic roof， followed by the insufficient support of the roadway.The support of the pumping pillar should have the characteristics of cutting， large cross-section， high load bearing and yield deformation.The combined support mode of "pumping pillar + anchor cable + W steel strip" is adopted to make the pillar and the surrounding rock of the roof and floor in a synergistic state， which can ensure that the fully mechanized working face can pass through the large cross-section roadway group safely.