Study on safety technology of anti-caving at a super-large section roadway with thick and fractural coal roof

Numerical simulation is applied to analyze surrounding stress distribution of individual cells and the reasons are proposed why roof caving easily happens at apex angle and at the center of roadway. Furthermore, based on key factors of roof caving and mechanics derivation of neutral axis's new position in roof beam, the superiority of prestressed truss cable and its key component--connector is thoroughly analyzed in safety management of anti-caving. Finally, according to the geometric size and abutment pressure influence of coal roadway No. 9101 in Danshuigou coal mine, prestressed truss cable combined control scheme and its corresponding parameters are designed by use of numerical simulation method and engineering analogue method, then the scheme have been put into practice on spot. The field observation results show that roof should be effectively controlled by the cable truss structure consisting of two long cables and one connector, which could prevent roof accidents fundamentally at a super-large section roadway with thick and fractural coal roof.