Determination of c and Φ from IDT and unconfined compression testing and numerical analysis

This paper presents an alternative criterion (simplified method) to determine the cohesion (c) and internal angle of friction (Φ) properties for two granular materials lightly stabilised with slag-lime and general blend (GB) cement-flyash using indirect diametral tensile (IDT) strength and unconfined compressive strength (UCS). The c and Φ values of the stabilised materials obtained based on this criterion were related to the IDT strength and UCS. The results suggest that the c and Φ can be estimated using this criterion and the c can be accurately related to either the IDT strength or UCS for lightly cementitiously stabilised granular materials. However, the IDT strength is a better characteristic than the UCS to estimate the c. In order to validate the criterion, the c and Φ obtained from the proposed criterion were input in the numerical analyses of IDT testing with Mohr — Coulomb failure criterion using FLAC2D finite difference software. The predicted tensile stress — horizontal diametrical deformation numerical results were compared with the corresponding experimental results. Based on this numerical analysis, it was found that the c and Φ parameters estimated from this method predicted the experimental results well in the elastic region but over predicted the ultimate stress.