Influence of carbonate content of marls used in dams: Geotechnical and statistical characterization

• Carbonates affect properties of marls due to alteration of cohesion by cementation.
• Moderate correlations due to different void ratios of specimens at preparation.
• Greater carbonate content increases permeability and lower the self-stability.
• Swelling potential decreased as the carbonate content increased.
• Preconsolidation stress decreased as carbonates increased due to particle crushing.

The relationships between geotechnical parameters identified from tests of slake durability, swelling behavior, soil dispersion, and consolidation, using samples of marls utilized to build impervious cores of Spanish dams, were analyzed. The analyses have determined the incidence of the processes of internal erosion and piping, self-stability, strength, durability (behavior during dry–wet cycles) and their variation with the carbonate content of marls.A total of 118 samples were selected from marl quarries used for the construction of three impervious cores of dams. The carbonate content of the samples varied from less than 10% to more than 70%. The type and amount of clay also varied. The results show that the carbonate content alters the short-term to medium-term cohesion of soils by the effect of possible cementation and break-up. The medium–low correlation indexes found in this work (although acceptable) are due to the complex mechanics of the durability and dispersibility phenomenons.