This paper presents experimental research concerning the shear behavior of two types of Italian peat, one normally, the other over consolidated. Organic soils are characterized by very high compressibility and high fiber content; two features that give rise to several problems during laboratory tests. Under consideration here are the effects of fibers and over consolidation on friction angle and stress-strain behavior. These are evaluated by means of undrained compression triaxial tests, with isotropic and anisotropic (K o ) consolidation being performed on natural and remolded samples. The experimental results are also analyzed by means of a bilinear failure criterion based on soil-reinforcement interaction mechanisms.

The design of a mooring system of a Wave Energy Converter is a challenging process that points out several unsolved technical problems, mostly related to the highly non-linear hydrodynamic phenomena occurring when high waves (e.g. 8 m high with 200 m wavelength) propagate in relatively shallow waters (e.g. 20 m). The aim of this note is to point out the relevance of the non-linear response of a WEC anchored in relatively shallow waters (shallow in the “non-linear” sense) in terms of loads applied to the mooring lines. Further, the effects of this cyclic load on the anchors is investigated. Note that to some extent it is like checking the importance of geotechnical and coastal engineers in the design process of the WEC structure and its mooring system (typically carried out by naval architects). The whole mooring design process is first outlined and then it is schematically applied to a specific case, namely a promising Italian device named SeaBreath (www.seabreath.it), in view of a possible deployment in the Adriatic Sea. The main concern of mooring designers is related to resonance effects induced by the second order drift. Therefore specific tests have been carried out in the 36 m long x 1.0 m wide x 1.3 m high wave flume of Padova University. Tests focused on the forces on the mooring lines induced by the sum of two regular waves of similar frequency. The mooring design is still far from complete: the physical model proved the relevance of the aforementioned effects but a numerical investigation (not yet performed) is required to draw final conclusions.

Design and construction of a mineral barrier layer involve many experimental and technological aspects. A specific soil water content and laboratory compaction energy, which are required to obtain permeability values according to the national regulation in force, must be determined. It is also necessary to control water content, compaction energy, and permeability of the liner actually compacted in situ. This paper shows how a compacted mineral barrier mainly composed of silty clay soil (the excavated soil is a natural but potentially re-usable waste product) was put in place to cover a large municipal solid waste (MSW) landfill and compacted using a heavy dumper, capable of achieving an adequate compaction degree. The in situ hydraulic properties of the liner were compared with those obtained by laboratory testing and to the limits imposed by the Italian regulation. The actual compaction degree was checked by in situ tests. Hydraulic conductivity tests were carried out in situ, using Boutwell and Guelph permeameters, and in the laboratory using rigid wall and flexible wall permeameters. In situ testing provided more realistic permeability values than laboratory ones and demonstrated that the actual construction procedure used was effective to obtain the design targets.

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Many curve-fitting procedures based on the Terzaghi uncoupled consolidation theory have been proposed for the determination of the laboratory coefficient of primary consolidation, cv. This paper presents data from ten oedometer tests performed on clay samples from three different sites, with the cv values having been obtained using four different fitting procedures.The in situ settlements of the clay layers were measured using borehole extensometers. In this way the in situ cv values of the same clay tested in laboratory were determined and compared with the laboratory values. At times, the four methods show considerable differences in the values of cv determinated in the laboratory. Casagrande’s method gives values that differ from those of the other methods and is not always easily usable. The other three methods provide a more consistent evaluation of the values cv. The comparison between in situ and laboratory cv values is not straightforward, since these findings show that the macrostructure of the soil layer influences the behaviour of the whole layer, and the laboratory cv values, apart from the method used for their determination, are sometimes unable to interpret the settlement over time