Effectiveness of reinforcing a low-height sandy slope with geosynthetic reinforcement for landscape development

Abstract

Landscape projects often require steep sandy slopes of low height, say 1–3 m, in many parts of the world, including Australia. Geosynthetic reinforcements may greatly help in constructing such steep slopes. In this paper, an attempt has been made to analyze the stability of a low-height medium dense sandy slope, reinforced with geosynthetic layers, so that this sustainable construction practice may be routinely adopted worldwide. The slope stability analysis was carried out using the limit equilibrium method as available in a commercial software, Slope/W. The slope angle was varied from 40° to 60°, and the effect of the following factors was investigated on the stability of the slope: depth, length, tensile strength and number of reinforcement layers, and soil-reinforcement interfacial friction coefficient. The analysis shows that installing a single geosynthetic reinforcement layer within the 40° slope at the optimum embedment depth (u) to slope height (H) ratio, u/H = 0.5, results in a stable slope with a factor of safety Fr(max) of 1.61, but this depth is not suitable for stabilizing the 50° and 60° slopes. Reinforcing the 50° and 60° slopes with two geosynthetic reinforcement layers at the optimum embedment depth of u/H = 0.14 and 0.5 in the 50° slope and u/H = 0.19 and 0.5 in the 60° slope improves the factor of safety over the unreinforced case, by 57% and 86%, to Fr(max) = 1.46 and Fr(max) = 1.36, respectively. An illustrative example has been provided to demonstrate the practical application of the developed graphical presentations, as the design charts, to practising engineers involved in landscape development.