Conditioning procedures to enhance the reproducibility of mud settling and consolidation experiments

Abstract

The means by which mud is conditioned for use in laboratory experiments affects the behaviour of the mud during the experiments, and hence the results and reproducibility. This study discusses the impact of different mud conditioning techniques and procedures using multiple series of short-term consolidation tests. The mud used originates from the Zeebrugge docks of the Port of Antwerp-Bruges, Belgium. For all experiments the initial density of the mud was around 1.08 g⋅ cm−3, which is below its gel density. This has the advantage that the comparison can be limited to the behaviour during the typical initial settling phases, allowing experiments to be restricted in time to seven days. Each series of experiments is repeated multiple times using two separate batches of mud. The objective is to quantify the repeatability across these different series of experiments, and to identify the ideal conditioning procedure for optimal reproducibility for future laboratory experiments using mud. Distinct differences in settling curves are observed which confirm the intended influence of each mixing technique. A conditioning procedure based on a combination of axial and radial mixing yields the most control over settling behaviour during the initial stages of the sedimentation process and therefore results in the best repeatability of settling behaviour. It is recommended that such a mud conditioning procedure is further used for experiments with mud to allow for a better uniformity in research where the behaviour of mud is critical.