Effect of setting load on the dynamic loading of powered supports

The paper examines the parameter values of dynamic loading which affect powered supports at different levels of initial static loading. It was established that the initial setting pressure which is applied to the legs after advancing the support unit has a considerable effect on the dynamic pressure levels and on the average pressure increase in the legs. Because of the magnitude and nature of the dynamic loading which the roof strata exert on the support unit, there is no advantage to be gained in the support legs being subjected to a greater pressure than po, which is the pressure needed to maintain the equilibrium of the rock mass immediately above the support unit.