Parametric study to characterize water-weakening effects in UDEC

The Universal Distinct Element Code (UDEC) has been rising much prevalence and is a validated technique applied to simulations in varied branches of geotechnics. Nevertheless, the characterization of water-weakening effects on a rock model remains elusive, resulting in a poor constraint referring to water-induced simulations by UDEC. In this context, previous research has been attempting to conduct an intuitive link between modelling parameters and saturation degrees, S_r, to implement a water-weakening process in UDEC, leading to a detrimental potential devoid of the basic logic that modelling parameters determine macroscopic properties of a rock model in contrast to dominance by S_r owing to the discrepancy in a physical sense and spatial scale. To fill in this gap, a new methodology coupled with a parametric study is first proposed with procedures that macroscopic properties of actual rock with different S_r are input into parametric relations to acquire predicted modelling parameters, which will be sequentially calibrated and adjusted until simulations are in line with actual tests. Utilizing this methodology, water-weakening effects on macroscopic properties, mechanical behaviours, and failure configurations of numerical models in UDEC are commensurate with tested ones to the utmost with noticeable computational expediency harnessing the benefit of the parametric study, indicating the feasibility and simplicity of the methodology. Thus, in the implementation of a water-weakening process in UDEC, we suggest converting an embarking from an intuitive link between modelling parameters and S_r into a parametric analysis to determine modelling parameters according to macroscopic properties under different S_r.