Sediments from natural geological hinterland accumulate inside waterways and man made accumulations on land. Their grain size distribution and mineral composition are comparable with soils. Accumulated mud reduces safe operation and functionality of these facilities. Thus, it should be permanently removed and disposed of inside the water body or on land. Industrial muds are also stored in man made accumulations on land. Due to high water content, strength of muds is usually lower than strength of soils with water content at liquid limit. Some muds exhibit thixotropic behaviours.
In this thesis, the validity of in situ and laboratory test methods and material models, developed for soils, for the identification of mud properties and for the prediction of their behaviour, were investigated. Two muds were examined: dredged marine sediment – reful from the Port of Koper and red gypsum mud, which is by-product in the production of titanium dioxide in Celje. Both are deposited on land, in accumulations which present limitations in the planning of the infrastructure and production. Reful is deposited in shallow lagoons, while red gypsum mud is stored behind two large embankments Za Travnikom and Bukovžlak, which represents high risk facilities.
Properties of muds were identified with in situ and laboratory investigations. Results were interpreted in the light of classical soil mechanics, taking into account the specificities which emanate from the mud origin and from new sedimentation environment. The influence of salty pore water on the index properties of reful was determined. The limitations of in situ measuring sensors for the investigation of muds were checked. The validity of semi empirical relationships, developed for evaluation of in situ tests in soils, for the description of red gypsum mud properties were analysed. ConTec Viscometer 5, designed for mortars and concrete, was recognized as suitable also for rheological investigations of muds. The sensitivity and thixotropic behaviours of muds were evaluated. The improvement of reful was investigated by mixing it with inorganic binders.
From the results of laboratory tests and from trial pressure filtration tests, technological and material parameters for model description of consolidation creep, drying and pressure filtration, were estimated. Results show that Soft soil creep model is suitable for the description of consolidation creep, while basic 1D model, developed for the computation of the Slano Blato landslide drying, is not completely appropriate for the description of drying of mud in the accumulation and oedometer test is suitable also for the prediction of the pressure filtration parameters.
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