Abstract:

In order to solve the difficulty in stability control of gob-side roadway under gradient coal pillars in ascending mining, taking the auxiliary transportation roadway of 1206 working face in Yushujing Coal Mine as the engineering background, the deformation and failure mechanism of gob-side roadway is revealed by field investigation, theoretical analysis and field test. Based on the theory of collaborative support, the design scheme of sectional collaborative support is put forward, and the control effect is verified by the deformation monitoring of roadway in field test. The research shows that the causes of large deformation and failure of auxiliary roadway in No. 1206 working face are poor mechanical properties of surrounding rock, water softening, engineering stress disturbance and gradual narrowing of coal pillar. According to the elastic-plastic theory calculation, the minimum width of the protective coal pillar for the gob-side roadway is 15 m. Based on this, the roadway is divided into three influence sections: strong, medium and weak sections and the control countermeasures of different sections are formed and applied on site. The monitoring data show that the cumulative deformation of the roadway surrounding rock is reduced by more than 30% after applying the new technology, and the surrounding rock large deformation of the gob-side roadway with gradient coal pillar in the ascending mining is effectively controlled.