Title:
The Influence of Seepage Velocity on Chloride- Transport in Underground Concrete Structures under Hydro-Static Pressure (Prepublished)
Author(s):
Limin Lu, Qingli Zhao, Jinwen Sun, Yingzhi Zhang
Publication:
Materials Journal
Volume:
Issue:
Appears on pages(s):
Keywords:
chloride ions; hydrostatic pressure; saturated concrete; seepage velocity; unsaturated concrete
DOI:
10.14359/51750668
Date:
4/9/2026
Abstract:
Hydrostatic pressure has a significant impact on the transportation of chloride ions in concrete, especially in underground structures and marine environments. This paper proposes a new seepage velocity model that considers the combined effects of hydrostatic pressure and initial hydraulic gradient on chloride ion transport. By combining saturated and unsaturated concrete seepage models and convection-diffusion coupled chloride ion transportation analysis, the influence of hydrostatic pressure and seepage velocity on chloride ion transport in concrete is studied. Experimental verification shows that the proposed model can accurately predict the concentration distribution of chloride ions. The analysis results indicate that the seepage velocity under hydrostatic pressure is not only positively correlated with the permeability coefficient of concrete and hydrostatic pressure, but also negatively correlated with the initial hydraulic gradient, and has a significant impact on the transient seepage characteristics of unsaturated concrete. The effect of seepage velocity on the chloride ion transportation process exhibits nonlinear characteristics. Before a critical value, seepage velocity promotes the transportation of chloride ions, while after exceeding this critical value, the influence gradually decreases. Based on this conclusion, it suggests that in the durability design of underground concrete structures, a chloride ion transportation model considering the convection-diffusion coupled effect should be adopted for a more accurate prediction on the service life of the structure.