NUMERICAL MODELLING OF SPATIALLY VARIABLE PERMEABILITY OF CEMENT-ADMIXED CLAYS

Abstract

Cement-admixed soils exhibit spatial variability. However, current literature focuses on the strength variability of cement-admixed soils. This thesis presents a framework for modelling the random variation in permeability in cement-admixed clays based on the binder content variation, thereby relating the coefficient of permeability to its unconfined compressive strength. The strength-permeability relationship was subsequently implemented in random finite element method (RFEM). Using coupled-flow RFEM, the effects of spatial variation in strength and permeability on the one-dimensional (1D) consolidation behaviour of cement-admixed clays were examined. Engineering problems like cement-admixed clay slabs in excavations and airfield pavements overlying cement-admixed clays were also considered. Results show that excavation stability was dominated by strength and stiffness of the cement-admixed clay, rather than permeability. However, for consolidation problems, the effect of spatially variable permeability on the consolidation rates depended on the SOF configuration. Spatially variable permeability also led to more significant differential settlement in airfield pavements.