Abstract: When a breach occurs in river embankment,prompt measures must be implemented to seal the opening effectively.Among various countermeasures,steel mesh gabions are widely employed due to their advantages in utilizing locally available materials and enabling rapid deployment for breach closure.However,the motion trajectory of steel mesh gabions is significantly influenced during water entry by complex hydrodynamic factors such as water depth and flow velocity.Therefore,it is essential to investigate the water entry behavior of steel mesh gabions under varying operational conditions to establish quantitative relationships between landing distance and key parameters including water depth and flow velocity.This study systematically examined the water impact process of reinforced gabions based on the fundamental principles of the volume of finite (VOF) method under different combinations of water depth,flow velocity,side length,and filling density.Fitting curves for landing displacement and landing time under variable conditions were derived through numerical analysis.The results show that the horizontal landing distance of steel mesh gabions exhibits a positive correlation with both water depth and flow velocity,with the respective fitting curves well represented by a linear function and a fourth-order polynomial function.In contrast,an inverse relationship is observed between the side length of the gabion and the density of the filling material,where the corresponding fitting curves follow exponential and fourth-order polynomial functions,respectively.To ensure effective bottom sealing of the Tuanzhou embankment breach,the minimum required side length and filling density of the steel mesh gabion should be determined according to the prevailing flow velocity.Present studies provide theoretical insights and data support for the design and development of related emergency response equipment.