Hydro-mechanical properties of compacted chalk

Abstract

Historically, chalk has always been widely used as a building material in public works projects such as dams, dikes and pavements. Given its characteristics as an evolving rock, its properties and behavior are well mastered by its users, not always with rational but rather empirical methods. This study examines the hydro-mechanical behavior of chalk correlating these findings with its physical and microstructural characteristics. The results highlight the potential for applications in geotechnical engineering, particularly in the design and construction of embankments and dikes, notably within the framework of the Seine–Nord Europe Canal project. Hence, the behavior of different types of compacted chalks sourced from two sites in northern France, Haubourdin and Roye, are examined; highlighting the effect of density and water content on their hydro-mechanical performance such as strength, stiffness, ductility and compressibility. Physical properties, macroscopic classification tests and microstructural investigations are analyzed including Infrared Spectroscopy, X-ray Diffraction, Mercury Intrusion Porosimetry (MIP), as well as Scanning Electron Microscopy (SEM). Moreover, drying and wetting tests were carried out to study the water sensitivity of both chalks. Furthermore, macroscopic mechanical behavior of compacted chalk samples is examined under different loading conditions such as oedometric K 0 compressibility, permeability, drained and undrained triaxial shearing tests. The findings contribute to a better understanding of chalk’s performance as a construction material, using local resources in large-scale civil engineering projects.

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