ABSTRACT
This study assesses how variations in carbonate content affect the shear strength of beach sand from Caucaia, Brazil, a region where specific data on coastal sands’ behaviour are limited. Recognizing the relevance for maritime constructions and offshore wind tower foundations, this research focused on two Northeastern coastal sand samples. These were subjected to direct shear tests under stresses of 50, 100, and 200 kPa, with carbonate content variations introduced through Cariri stone waste at low (less than 1%), medium (around 50%), and high (over 80%) levels. Findings reveal a direct impact of carbonate content on sand shear strength, with medium levels enhancing strength uniformly across samples. However, at high carbonate levels, responses varied, indicating a complex relationship between carbonate content and soil mechanical properties. One sample showed increased strength, while the other did not, suggesting a threshold effect where additional carbonate may not consistently benefit soil strength. This nuanced understanding challenges simplistic models of soil behaviour, emphasizing the need for detailed geotechnical analysis in carbonate-rich coastal areas. The study emphasizes the critical need to incorporate carbonate content assessment into the geotechnical evaluation for coastal infrastructure design. It provides foundational data that advances the understanding of soil behaviour in carbonate-enriched environments, essential for optimizing the construction and stability of maritime and wind energy structures.
