Hanbing Bian

Highway embankments with carbonaceous mudstone fill material are prone to deformation and instability under traffic loading and rainfall owing to particle breakage-induced stiffness and strength degradation. This study aims to investigate the particle breakage characteristics of carbonaceous mudstone fill material under dynamic loading with prior seepage conditioning, and to establish a permeability model considering breakage behaviour. To this end, a custom-designed testing apparatus was employed to conduct dynamic loading and permeability tests on specimens with varying coarse particle content (CPC) under different dynamic loads and seepage durations. Changes in particle size distribution, average saturated permeability coefficient and relative breakage ratio were analysed, and a permeability model relating the coefficient to the breakage ratio was proposed. The results indicate that the dynamic loading-affected range in the upper part of the specimens increases with higher CPC and greater loading levels. When CPC is below 40%, permeability changes little, whereas significant local variation occurs at higher CPC. A threshold dynamic load of 40 kPa, particularly at a CPC of 40%, was identified as the condition that triggers particle breakage and induces abrupt changes in seepage behaviour. The developed model effectively captures the nonlinear relationship between permeability and relative breakage ratio.

This paper investigates the dynamic response of water‐saturated concrete under high stress levels, with a particular emphasis on the role of pore pressure. An enhanced elastoplastic damage model, incorporating dual plastic mechanisms, is proposed to capture the coupled hydromechanical behavior of concrete under combined high stress and high strain rate loading. Key improvements include the refinement of the porosity‐volumetric strain relationship, the incorporation of full hydromechanical coupling under dynamic loading, and the integration of strain rate sensitivity into the pore collapse mechanism and material strength. The improved constitutive model and numerical methodology are validated through simulations of uniaxial tensile tests and three sets of compression tests. Parametric studies are conducted to explore the influence of pore pressure on the confined response of concrete under both static and dynamic loading conditions. The results demonstrate that interstitial pore pressure significantly affects both the volumetric and deviatoric behaviors of saturated concrete, with its influence becoming more pronounced under dynamic loading. The findings provide valuable insights into the hydromechanical behavior of concrete structures subjected to extreme loading scenarios.