Author(s): Ana Maria Ferreira Da Silva; Mohsen Ebrahimi; Mareen A. Lenz
Linked Author(s): Ana Maria Ferreira da Silva
Keywords: Movable bed; Immobilization; Sand-cement mixture; Granular roughness; Shear strength
Abstract: This paper presents a new method to immobilize sand in laboratory channels. The motivation for the present work was to develop a method that would: 1- not involve the use of harsh chemicals; and 2- ensure that the granular roughness of the original bed would not be appreciably changed. The resulting method involves coating the surface with a mixture of sand and a small amount of Portland cement. The first part of this paper is intended as a report of the laboratory tests carried out at Queen’s University to develop the method, and more specifically to determine the optimal amount of cement and effect on roughness, as well as gain insights into the shear strength and durability of the hardened layer. On the basis of these tests, it was found that the method can be used to fix both flat and deformed beds, with the hardened layer being strong enough to withstand a wide range of typical laboratory shear stresses. The method was found to be particularly effective for sands up to 1. 1 mm, when it is possible to ensure that the granular roughness of the fixed bed is comparable to that of the movable bed by merely using in the coating mixture a coarser sand than the original one. In the second part of the paper, additional experience with the method acquired through a recent research application, involving the immobilization of a train of dunes in a flume, is reported.