Geosynthetics are increasingly used in retaining structures, foundations, in situ slopes, embankments and pavements. New developments in geosynthetics have offered engineered solutions for drainage, filtration, separation, reinforcement and stabilisation. In the case of reinforcement action, analysis of internal stability by interface experiments such as pull-out tests are conducted to assure the strength, effectiveness and integrity of the reinforced earth system. This paper briefly attempts to explain the response to force-deformation behaviour of a pull-out test which assumes to integrate the total shearing actions along the length of the reinforcement. A simple 1D non-linear elastic formulation has been developed for the interface equilibrium of highly extensible geosynthetic reinforcements. The interface pull-out equation has been idealised by an elastic-plastic relation to analyse the deformation responses. Although no closed form solution exists for the governing interface equation, the pull-out expressions (in non-dimensional form) were numerically solved through use of the finite difference technique. Internal stability responses in terms of load-displacement relations and the variations of pull-out force and deformations along the reinforcement length were illustrated for ranges of relative stiffness and bond resistances of soil reinforcement. The predictions from the analysis are validated with experimental pull-out test results for various geotextiles, polymers, nylon geosynthetics and steel strap reinforcements. (a).
Abstract