The Coal Face Failure Controlling Mechanism and Parameter Optimization of ‘Manila + Grouting’ Technology in a Large-Cutting-Height Panel

With the exposure of these problems of low ductility, easy breakage and high cost of grouting anchor cable, the application of “manila + grouting” full length anchorage technology in the prevention and controlling of coal face failure is more and more widely, the key procedure of which is the selection of manila diameter. Aiming at the difficulty of the choice of reasonable manila diameter, the uniaxial compressive and the wedge shear test of grouting coal samples with manila at different manila diameters were performed using the rock mechanics testing machine. The study shows that: The existence of manila extends the deformation of grouting coal samples and improves the tensile strength of coal samples; The manila has good ductility and high shear strength and the damaged coal body of coal face will not fall down immediately due to the function of manila; The uniaxial compressive strength and residual strength value of coal samples with an appropriate diameter of manila in it can reach the maximum, and the effect of the prevention and controlling of coal face failure is better and the cost is lower. It is concluded that the research result can provide the theory foundation for the “manila + grouting” full length anchorage technology.