Failure mechanism recognition and optimum support design of roadway groups in soft and fractured surrounding rock - case study: Paner coal mine

As increasing number of coal mines turn to deep mining stage, stability control of surrounding rock in deep roadway groups has become a major technical problem. Based on the roadway groups in shaft station of second east mining area, Paner coal mine, the characteristics of deformation split of surrounding rock, failure of supporting structure, and asymmetric deformation mechanism of roadway are analyzed. It is concluded that the soft and fractured surrounding rock, lower supporting intensity, especially the almost orthogonal between strike direction of roadway and direction of maximum horizontal primary stress are the main causes of roadway deformation characterized mainly by wall-to-wall convergence and floor heave. Besides, the asymmetric deformation mechanism of roadway can be explained by the flexural deformation and high-stress squeezing of surrounding rock starting at the position of right sidewall and floor corner of roadway due to the smaller lateral confinement from inclined rock mass structure. Based on the above analysis, a combined multiple-step control countermeasure for roadway groups with soft and fractured surrounding rock are put forward. Moreover, through numerical analysis and field monitor measuring, the control countermeasure is analyzed and verified which indicates that it-is rational and efficient for the stability control of surrounding rock in deep mining engineering.