A Simplified Approach to Estimating the Collapsible Behavior of Loess

Due to the particularity and complexity of loess, it is challenging to estimate its collapsible behavior numerically at present. This paper aims to propose a simplified approach, which is named as the modulus reduction method, to estimate the collapsible behavior of loess. For loess upon wetting, the modulus reduction method assumes that loess collapses as a result of strength reduction due to the additional stress induced by increasing bulk density. Thus, special attention is given to the confirmation and determination approaches of bulk density and deformation modulus of loess upon wetting. Subsequently, a comparative numerical analysis based on the modulus reduction method and the force-water equivalent method, which is commonly used for the analysis of negative skin friction on piles in collapsible soil, is investigated. It turns out that the result obtained by the modulus reduction method is more consistent with the collapse mechanism of loess compared with that derived by the force-water equivalent method. Finally, a case history concerning a published field test of loess upon wetting is studied, and the result shows that the simulated deformation characteristics by adopting the modulus reduction method agree excellently well with the measured data. The case study validates that the modulus reduction method is feasible to analyze the collapse of loess and suitable for the numerical simulation involving collapsible loess