THE THEORY OF REINFORCED EMBANKMENTS . REINFORCED EMBANKMENTS. THEORY AND PRACTICE. PROCEEDINGS OF THE CONFERENCE REINFORCED EMBANKMENTS, THEORY AND PRACTICE IN THE BRITISH ISLES, ORGANISED BY MMG CIVIL ENGINEERING SYSTEMS, HELD AT CAMBRIDGE UNIVERSITY, SEPTEMBER 27 1989

The mechanics of an embankment constructed on a layer of reinforcement over a soft foundation are discussed in a design context in this paper. Methods of analysis are reviewed for both stability and deformation. The role of reinforcement in improving short term stability and restricting lateral displacements is explained and illustrated. The concept of a 'fully reinforced' embankment is also discussed. Lateral stresses within the embankment give rise to outward-directed shear stresses at the base. In a reinforced embankment, these stresses are transferred to the reinforcement. The embankment may then be likened to a footing bearing on the foundation and the stability may be calculated using plasticity theory. If the embankment is sufficiently reinforced, the extrusion of the foundation soil is restrained by the reinforcement, to which outward-directed shear stresses are again transferred. Limit equilibrium methods provide an alternative, more versatile means of analysis but must be employed with discretion. In particular, slip circles extending through both the foundation and the embankment should not be used where the foundation depth is limited. Realistic analysis of deformation requires the use of finite element methods. Only limited checks can be performed in a routine manner for embankment serviceability and allowable reinforcement strain. However, simple and satisfactory methods exist for calculating an upper limit to lateral displacement in a fully reinforced embankment and for calculating long term settlement. (Author/TRRL)