This paper presents the preliminary results of experimental research into the stabilization of clayey sediments dredged from the Port of Taranto (Italy) with cement and (or) lime. First, the physical properties of the natural sediments are briefly described and compared with those of the same sediments when treated with different additives and cured up to 4 years. In particular, the effect of the treatment on the soil plasticity properties is originally analyzed in terms of plasticity paths. Then, the influence of the different stabilizing agents on the compression behaviour of the dredged soil is analyzed and methods for quickly predicting the admixed-soil behaviour are presented.

The paper discusses the geological history, intrinsic properties, structural features and mechanical behaviour of three differently fissured clays outcropping within the Apennine chain in southern Italy. Based on a large experimental database, the mechanical behaviour of the clays is investigated in the light of their different fissuring features, which have been distinguished and characterised by means of a new chart. The study assumed the soil to be a continuum, despite the different fissuring features of the clay fabric. Therefore laboratory tests were carried out on both natural and reconstituted clay samples, and the results were compared with those recognised in the literature to be typical of unfissured sensitive clays. Based on these comparisons, a behavioural framework is proposed for clays possessing certain fissure structures. The results of the analysis show that the mini- to mesostructure of clays of fissuring intensity I5–I6 can be modelled as part of the structure variable controlling the clay behaviour. Where the structure variable refers solely to the micro scale for unfissured homogeneous clays, for fissured clays I5–I6 it spans from the micro to the meso scale. As for the microstructure of unfissured clays, this micro- to mesostructure influences the soil response as an internal state variable in addition to specific volume in controlling the mechanical response. In particular, it appears that for clays of fissuring intensity I5–I6, structure is detrimental to strength, so that the material is even weaker than the reconstituted clay.

The revitalisation of the global economy after the Covid-19 era presents environmental geotechnics with the opportunity to reinforce the need for a change in paradigm towards a green, circular economy and to promote aggressively the use and development of sustainable technologies and management practices. This paper aims to assist in this effort by concentrating on several thematic areas where sustainability solutions and future improvements are sought. These include the re-entry of construction and demolition of wastes, excavated materials, industrial wastes and marine sediments into the production cycle and the reuse of existing foundations. Despite the recent trend in advanced countries towards recycling and waste-to-energy thermal treatment, landfills still constitute the most common municipal solid waste management practice, especially in low-and-middle-income countries, and technological solutions to improve their environmental footprint are hereby presented. At the same time, remediation solutions are required to address the multitude of contaminated sites worldwide. Advanced developments that incorporate environmental, economic and social dimensions are expounded by the authors, together with sustainable ground improvement solutions for infrastructure projects conducted in soft and weak soils. The topic of thermo-active geostructures concludes this paper, where, apart from their infrastructure utility, these structures have the potential to contribute to the renewable energy source.

The diagnosis of landsliding at the slope scale resulted from synergic geohydromechanical analyses of the slope factors, which should represent the first step to assess landslide hazard. According to the methodological approach discussed in the paper, the landslide hazard analysis should start from a phenomenological interpretation of the slope behaviour, including the definition of the slope factors, getting then to a quantitative prediction of the slope evolution with time. This quantitative evaluation should result from limit equilibrium analyses and numerical modelling, both of them performed considering the outcomes of the phenomenological reconstruction. Therefore, the understanding of the slope factors and of the landslide mechanism at the slope scale should drive the landslide hazard assessment, through analyses performed for different levels of diagnosis (phenomenological, analytical and numerical). Some landslides, representative for chain slopes in the Italian peninsula, are discussed in the paper in order to show the maturity of the geohydromechanical diagnosis of landslide hazard and, hence, to properly design the mitigation actions. A methodology for intermediate to regional landslide hazard assessment, based on geomechanical interpretations, is finally proposed.