ABSTRACT
The reinforced void problem is reexamined with special focus on the load-strain-time-dependent behaviour of the geosynthetic reinforcement. In current analytical model approaches, a single-value (constant) estimate of reinforcement stiffness is used for the design of reinforced fills over voids. Hence, the choice of an equivalent (elastic) stiffness value requires careful consideration. A simple hyperbolic stiffness model proposed by the writers is shown to be a useful approximation to the constant-load isochronous creep-strain behaviour of these materials, at least at low load levels, which are applicable to operational (serviceability) conditions of geosynthetic-reinforced soil structures. The paper uses the UK method for the solution of the reinforced fill over a void problem to compute tensile load and strain for a prescribed surface deformation (or maximum reinforcement settlement). An empirical approximation is introduced that links the isochronous stiffness of the reinforcement to its ultimate strength when product-specific creep test results are not available.
