experimental investigation on the arching effect in granular materials by using the developed trapdoor apparatus

this paper discusses the arching effect as the formation of a stable arch in granular materials. for this aim, a developed trapdoor apparatus is designed in order to investigate the arch dimensions in term of the internal friction angle, average size and base angle of materials. observations show that for all tested granular ensembles, width and height of the arch increase with an increase in trapdoor width and a decrease in base angle. it is also found that the shape of the whole arches is governed by a parabola. in addition, for both constant values of trapdoor width and base angle, the increase in both the internal friction angle and density of granular materials leads to the increase in arch dimensions.