Abstract
The project aims to contribute to the advancement of knowledge on intermediate soil deposits commonly encountered in risk-sensitive areas, often associated to multiple geo-hazards that may negatively interact with strategic infrastructure networks. In Italy, but not limited to, typical geotechnical hazards facing risk-sensitive areas are predominantly: subsidence, seeping-induced erosion and failures of riverbanks, and earthquake-induced liquefaction. Geotechnical hazards can severely impact strategic infrastructures with heavy consequences on people’s lives and economic activities, as well as structural, infrastructure, cultural, and environmental heritage. Improvements in geotechnical approaches to analysis and mitigation of such geo-hazards, pointing toward increasing the resilience of strategic infrastructures in risk-sensitive areas, rely significantly on enhanced characterization of soil behavior. Risk-sensitive areas are predominantly located in a wide variety of natural depositional environments, such as alluvial plains, where intermediate soils (silty sands, silts, and sandy silts) are commonly found. Additionally, intermediate soils are common in man-made geotechnical structures such as riverbanks, hydraulic fills, dredging sediments and mine tailings. Due to the complexity of their behavior and consequent variability of their main physical and mechanical properties, the geotechnical modelling of intermediate soils is still relatively poorly understood. Existing characterization and interpretation approaches, typically developed for markedly cohesive-behavior soils (clays) or cohesionless-behavior soils (sands), show severe limitations for geotechnical engineering applications which involve intermediate soils, both in static and dynamic conditions. To overcome such limitations, this research: (a) provides a general framework for the geotechnical characterization and modelling of intermediate soils from a geotechnical perspective; (b) develops non-standard test procedures and a new generation of interpretation methods to better capture the main specificities of intermediate soil behavior; and (c) releases guidelines for incorporating the main features of intermediate soil in analytical and numerical approaches used in the professional practice. The project relies on a remarkable experimental base and on the complementarity of 2 Research Units which will share their in-situ and laboratory equipment. In-depth investigations, including traditional, unconventional, and advanced in-situ and laboratory tests, are performed on different types of soil mixtures at selected test sites, in risk-sensitive areas. Experimental results will be used to calibrate a variety of models available in the geotechnical literature, highlighting strengths and weaknesses of existing constitutive models, and consequently to propose protocols for the calibration of these models for intermediate soils.
Results achieved
A major outcome of the TRANSITION project was the completion of an extensive in-situ and laboratory investigation programme for the geotechnical characterization of intermediate soils at three representative sites, encompassing different soil mixtures and associated geotechnical issues. A key feature was the systematic use of non-standard CPTU and DMT testing procedures, with variable probe penetration rates and, for DMT, variable membrane pressurization rates, to investigate partial drainage effects and identify consolidation trends across the investigated intermediate soils. The in-situ results were interpreted in terms of degree of drainage, identifying the transition from undrained to partially drained and drained responses. Laboratory tests on undisturbed soil samples collected from the three test sites provided benchmark values of soil properties to support the development of improved correlations for the assessment of geotechnical parameters, explicitly accounting for the actual degree of drainage during testing.Dettagli del progetto
Responsabile scientifico: Laura Tonni
Strutture Unibo coinvolte:
Dipartimento di Ingegneria Civile, Chimica, Ambientale e dei Materiali
Coordinatore:
Università degli Studi dell'Aquila(Italy)
Contributo totale Unibo: Euro (EUR) 62.018,00
Durata del progetto in mesi: 24
Data di inizio
28/09/2023
Data di fine:
28/02/2026
