|Strength modelling of consolidating mud beds|
|Merckelbach, L.M.; Kranenburg, C.; Winterwerp, J.C. (2002). Strength modelling of consolidating mud beds, in: Winterwerp, J.C. et al. (Ed.) (2002). Fine sediment dynamics in the marine environment. Proceedings in Marine Science, 5: pp. 359-373|
|In: Winterwerp, J.C.; Kranenburg, C. (Ed.) (2002). Fine sediment dynamics in the marine environment. Proceedings in Marine Science, 5. Elsevier: Amsterdam. ISBN 0-444-51136-9. XV, 713 pp., more|
|In: Proceedings in Marine Science. Elsevier: Amsterdam. ISSN 1568-2692, more|
consolidation; mud; shear vane; shear strength; fractal; scale invariance
The research presented focusses on tile self-weight consolidation and strength evolution of soft underwater mud beds, A series of experiments was carried out in 1.5 m tall consolidation columns for a maximum duration of 95 days. Segmented settling columns were designed and built in order to provide. well-defined samples of the bed. the strength of which was measured using a high-precision rheometer equipped with a miniature vane.
The process of consolidation was modelled as a one-dimensional process using the Gibson equation  written in a Eulerian reference frame and with the particle volume fraction as tile dependent variable. The integration of the consolidation equation requires boundary conditions, initial conditions and constitutive equations for effective stress and permeability. The strength evolution is taken into account by a failure criterion which relates strength to effective stress.
Constitutive equations for effective stress and permeability and a failure criterion were derived based oil the concept of a scale invariant bed structure. The bed is assumed to be formed by aggregates. The properties of the aggregates are as assumed to be determined by the clay fraction only,. The averaged size of the aggregates determines the effective stress, permeability and shear strength. During consolidation the averaged size of the aggregates reduces, so that effective stress and shear strength increase and permeability decreases. The results of numerical modelling of the experiments agree well with measurements.