Earth Pressure near a Longwall Working Place

Abstract

The earth pressure around a longwall working place has been studied, taking into account several factors such as the balance of force, the supporting capacity of the overlying layers, and the retardation of the surface subsidence. As the results, the authors have derived a theory on the transition of stress conditions in the ground above a mined area ; that the earth pressure distribution in a goaf is at first very irregular but it becomes more and more uniform as time passes, as illustrated in Fig. 7, and that less irregularity is seen on the plane farther from the coal seam as shown in Fig. 6. This theory has proved serviceable to explain various facts that had otherwise never been understood.