The strength envelope of granular soil stabilised by multi-axial geogrid in large triaxial tests

Conventional methods of characterising the mechanical properties of soil and geogrid separately are not suited to multi-axial stabilising geogrid that depends critically on the interaction between soil particles and geogrid. This has been overcome by testing the soil and geogrid product together as one composite material in large-specimen triaxial compression tests and fitting a non-linear failure envelope to the peak failure states. As such, the performance of stabilising, multi-axial geogrid can be characterised in a measurable way. The failure envelope was adopted in a linear elastic perfectly-plastic constitutive model and implemented into finite element analysis, incorporating a linear variation of enhanced strength with distance from the geogrid plane. This was shown to produce reasonably accurate simulations of triaxial compression tests of both stabilised and non-stabilised specimens at all the confining stresses tested with one set of input parameters for the failure envelope and its variation wi...