Research on roof falling mechanism and support technology of mining roadway in expansive soft rock

It is easy to destroy in expansive soft rock roadway with the large deformation and roof falling. The key problems are the mechanism is not clear and the support scheme is not reasonable. Based on the 1202 track roadway in Lijialou Coal Mine, by conducting laboratory experiments, field measurements, theoretical analysis and numerical simulation, the mechanism of roof falling and reasonable support scheme were studied. The results showed: ( 1 ) there are mudstones in the 2 to 4 m roof of the 1202 track, the clay mineral content in the mudstone is as high as 70%, and the montmorillonite content is as high as 25%, therefore, the mudstone is easily disintegrated by water; ( 2 ) the reason of roof falling were the presence of weak interlayer in immediate roof, strong rainfall, moist air, unreasonable support scheme and low support parameters; ( 3 ) the new support method for expansive soft rock roadway was combined with support including bolt, metal mesh, steel ladder beam and reinforced anchor cable. Also its pre-tightening force and anchoring force should be improved to prevent immediate roof separation and the lack of pulling force of the top suspension. The on-site monitoring system showed that the total separation of the roof of the roadway was 12 mm with the advancement of working face. The surrounding rock is at good conditions. © 2020, Editorial Office of Journal of Mining and Strata Control Engineering. All right reserved.