Stresses in planar soil reinforcements

Geosynthetics are often used in soil reinforced applications. However, there are currently no methods for estimating reliably the stresses within the reinforcements at working load levels. This paper summarizes simple closed form solutions based on elastic shear-lag analysis for describing the tensile stresses measured in planar soil reinforcements in plane strain compression. Reinforcement stresses are expressed as closed form functions of the inclusion geometry, elastic properties of the constituent materials (soil and reinforcement), stress level and interface friction. The solutions are used to interpret data from a new laboratory device, the Automated Plane Strain Reinforcement (APSR) cell. This equipment measures the maximum tensile stresses that develop at the center of a single planar inclusion due to shearing of the surrounding soil. Test data, obtained for an instrumented steel sheet inclusion embedded in Ticino sand, demonstrate that the shear-lag analysis predicts reliably the stresses in the reinforcement in the APSR cell at working load levels.