Lengthening Anchor and Cluster Pillar Combined Strengthen Support Technology for Secondary Mining Coal Roadway

In order to resolve the problem of secondary mining roadway with serious surrounding rock deformation at fully mechanized top-coal caving face in Yangmei 2^# Coal Mine，through the theoretical analysis of the difficult supporting in secondary mining coal roadway and the defects of original supporting scheme，lengthening anchor and cluster pillars combined strengthen support scheme was put forward. According to practice， the numerical simulation software is used to simulate reinforced roadway surrounding rock deformation characteristics，the convergence of roof-to-floor decreased by 71.3%, percentage reduction of area reduced from 80% to 17% by the original supporting scheme. The results showed that the technical effect of lengthening anchor and cluster pillars combined strengthen supporting technology was good，it could effectively connect massive structure formed by anchor bolt support with deep surrounding rock in soft rock roadway，and maintained roadway stability.