Modelling tensile/compressive strength ratio of artificially cemented clean sand

The present work proposes a new theoretical model for predicting both the splitting tensile (qt) and compression strengths (qu) of artificially cemented sands and assesses their ratio for a given material. The proposed developments are based on the concept of superposition of failure strength contributions of the sand and cement phases. The sand matrix obeys the critical state soil mechanics concept, while the strength of the cemented phase can be described using the Drucker-Prager failure criterion. The analytical solutions are challenged against experimental tests on three different cemented clean sands, cured for different time periods. While the analytical relation fits well the experimental data, it also provides a theoretical basis for the explanation of some features related to the experimentally derived strength relationships for cemented clean sands. The value of the power relationship between strengths and the porosity/cement ratio index seems governed by soil matrix properties, while the dependency between the strengths and the curing time can also be captured. For a given cemented sand, the model equally confirms the existence of a unique tensile/compressive strength (qt/qu) ratio, independent of the curing time and primarily governed by the compressive to tensile strength ratio (or the friction properties) of the cement. It is also confirmed that the qt/qu ratio changes within a narrow range for different frictional properties of the cementing phase.