Finite-element study of arching behaviour in reinforced fills

The results of a finite-element parametric study, performed to investigate the nature of soil arching in the geosynthetic-reinforced fill above a void, are presented. The fill response to the formation of a void is compared with the arching theories of Terzaghi and Hewlett and Randolph. It was found that Terzaghi's approach is capable of describing all aspects of behaviour observed in numerical analyses, whereas Hewlett and Randolph's formulation may only be applied to a limited number of cases. It was also found that the accuracy with which Terzaghi's approach predicts the vertical stress at the base of the fill layer depends mostly on the value of the stress ratio K in the shear zone propagating from the edges of the void. The values suggested in the literature are shown to be too low, resulting in a highly overestimated vertical stress at the base of the fill. A suitable value of K is suggested from the numerical results, which is independent of the shape and size of the void, and of the fill and geosynthetic properties.