Suppression of Soil Dilation—A Reinforcing Mechanism of Soil-Geosynthetic Composites

Abstract

The presence of geosynthetic reinforcement in soil mass has been shown to reduce the tendency of dilation of the soil when subject to shear stress, especially when the reinforcement is closely spaced. As tensile loads are induced in geosynthetic reinforcement, adjacent reinforcement layers tend to act as tensioned membranes that inhibit dilation of the soil enclosed between the reinforcement layers. The suppression of soil dilation leads to stronger soil and is regarded as a reinforcing mechanism. This paper presents for the first time measured volume change behavior of field-scale experiments on reinforced and unreinforced soils. The volume change behavior, as characterized quantitatively by the angle of dilation, is presented and discussed. This paper also describes finite element analysis for the stress–strain and volume change behavior of field-scale soil-geosynthetic composites. Using the calibrated finite element model, a parametric study was conducted to examine the effects of reinforcement spacing, reinforcement stiffness, and soil stiffness on volume change behavior of soil-geosynthetic composites. The measured data and finite element analysis results suggest that the mechanism of suppression of soil dilation (addresses volume change behavior), and the mechanisms of apparent confining pressure and apparent cohesion (two popular mechanisms that address strength behavior) are likely independent.