Safety factor calculation of a road structure with cement-modified loess as subgrade

Abstract

The deformation and failure parameters of six mixtures of cement-modified loess have been determined based on direct tensile stress testing, indirect tensile test testing and unconfined compressive stress testing. Results have been used to determine the parameters of the Mohr-Coulomb failure criterion and the parameter of the Hoek-Brown failure criterion. The Hoek-Brown model clearly shows that results from indirect tensile stress measurement must be weighted to describe materials properly. Both models’ results were then used to calculate the safety factor of a road structure with cement-modified loess used as subgrade material using reduction techniques. Specifically, for the Hoek-Brown model, a new calculation adapted to structures with tensile stresses is proposed. Results vary by around 8.9 for the Mohr-coulomb model and around 3.2 for the Hoek-Brown model.This shows, at the laboratory scale, that resource-based economies could be expected if cement-modified loess mechanical parameters were considered in the design of structures. It also shows that the Hoek-Brown model is a promising tool to study tensile stressed structures made with cement-modified materials.