6 / 2025-04-24 11:27:03

Impact of water salinity on internal erosion of earthen hydraulic structures

Percolation and runoff from intense rainfall can dissolve salts naturally present in the soil, which will alter the water chemistry and affect the stability of earthen hydraulic structures, especially in coastal regions. The infiltration of salt contaminated water through clay soils promotes flocculation, due to the compression of the electrical double layer, altering soil properties and its erosion resistance. This study investigates the effects of hydraulic head and salinity on the suffusion of clayey sand mixtures. Results show that higher salinity reduces eroded mass, with Kaolinite fines being eroded more than Illite, and NaCl solution resulting more erosion than CaCl₂. These behaviors align with the dispersive properties of fines at different saline conditions. The effect of hydraulic head on erosion decreases as the ionic strength of percolating water increases, becoming nearly negligible at high concentrations of CaCl₂. These findings highlight the importance of considering ionic composition of pore water when assessing the stability and resilience of earthen structures against saline intrusion.