DESIGN AND CONSTRUCTION OF REINFORCED EMBANKMENTS OVER WEAK FOUNDATIONS

Abstract

Experience with design and construction of reinforced embankments over saturated clay foundations is reviewed. Reinforcement materials considered are geotextiles and geogrids. The effects of tensile reinforcement include increased embankment stiffness and reduced shear stress and strain magnitudes and plastic deformations in the foundation. Analysis results show that reinforcement reduces embankment settlement and lateral spreading due to undrained constant-volume distortion. The conditions under which these performance improvements are significant are described. Limit equilibrium design procedures are discussed. Available information indicates that modified classical stability procedures are suitable for relatively uniform clay foundations. Their applicability to peat foundations appears to be more limited. Aspects of limit equilibrium analyses specific to use of reinforcement are discussed. These include (a) effect of the reinforcement force, (b) orientation of reinforcement force, (c) selection of reinforcement force for design, and (d) reinforcement embedment length. Simple design charts and figures presented can be used to make a preliminary assessment of overall factors of safety against foundation bearing capacity and slip surface failures and lateral sliding of the embankment. Last, construction aspects are described.