Elastic Theory Applied to Reinforced Earth

Reinforced earth is considered as being comprised of soft layers alternating with closely spaced extremely stiff, but extremely thin layers. This model was suggested for natural soil stratification by Westergaard and for artificially reinforced earths by Vidal. The stress-strain response of this model is shown to be determined by the limiting value of the product of the relative stiffness and relative thickness of the reinforcing layer. When tE₂/E₁ is infinite, the Westergaard material is described, but when tE₂/E₁ is zero, the reinforcement is ineffective. Finite, nonzero values of tE₂/E₁ describe intermediate degrees of reinforcement, referred to in this paper as the general material. Both the Westergaard and the general material are special cases of a cross-anisotropic elastic body, with the general material covering the full range encountered in practice. Example solutions are presented and the calculations of the actual stresses in the individual soft and stiff layers outlined. These calculations enable the design of the reinforced earth system to be performed.