Rheology of Clay Rich Soft Sediments: From Fluid to Geo- Mechanics
Type:
Presented during:
CEDA Dredging Days 2021
Authors:
E. Meshkati, A. Talmon, D. Luger, and A. Bezuijen
Abstract
Dredging industry is moving towards interdisciplinary endeavors where different disciplines are combined to provide better answers to emerging problems. One of these interdisciplinary applications that is becoming increasingly important concerns reuse and management of soft sediments in which often knowledge and expertise from fluid mechanics and geo-mechanics is required to support engineering aspects of a project.
Soft sediments such as natural mud, and clay rich industrial substances are neither a fluid nor a solid, but somewhere in between: known as non-Newtonian fluids in fluid mechanics and viscoelastic solids in geo mechanics. These materials are characterized by their complex time and (shear-)strain dependent rheological properties. Although these rheological behaviors are documented in literature, each discipline uses different terms, definitions, and approaches to describe and quantify them. The difference in language and approach often raises difficulties in communication not only between experts and clients but also even between experts themselves. In this paper we attempt to describe some of the fundamental rheological properties of soft sediments. This includes some of the main rheological (material) properties, accompanied with methods to determine them. It is emphasized that different engineering applications require knowledge on different sets of rheological properties, using different tools, methods and protocols, depending on both governing hydrodynamic/geotechnical conditions and physicochemical properties of materials. Lastly, the differences and similarities between fluid and geo-mechanics approaches when it comes to rheology are discussed.
Keywords: Rheology, Non-Newtonian Materials, Natural Muds, Clay-rich Industrial Substances, Dredging.