103,226 research outputs found
Natural zeolites, par G. Gottardi et E. Galli, 1985
No full textCesbron Fabien. Natural zeolites, par G. Gottardi et E. Galli, 1985. In: Bulletin de Minéralogie, volume 109, 6, 1986. pp. 697-698
Natural zeolites, par G. Gottardi et E. Galli, 1985
No full textCesbron Fabien. Natural zeolites, par G. Gottardi et E. Galli, 1985. In: Bulletin de Minéralogie, volume 109, 6, 1986. pp. 697-698
Integrated Physical and Numerical Modelling to Study the Hydro-Mechanical Response of a River Embankment
No full textDue to the increasingly frequent occurrence of extreme events related to climate change, the in-depth study of exceptional rainfall and flooding on earthen structures is essential. In particular, the associated consequences in terms of economic and human losses have caused the urgency of developing forecasting tools that can ensure a proper evaluation of expected impacts.
In this regard, the paper reports the numerical modelling of a small-scale centrifuge test performed to study the hydro-mechanical response of a river embankment typical of the Alpine and Apennine tributaries of the Po River (Italy). The purpose was to set up a well-validated numerical model that may be used for fore-casting the behavior of river embankments under critical scenarios. In particular, the proposed fully coupled numerical modelling considers the partial saturation conditions of a compacted silty sand river embankment subjected to flooding. First, the numerical model parameters were carefully calibrated based on the results of laboratory tests conducted on the soils constituting the physical model. Afterwards, the model was validated by comparing the results of the simulation with the experimental data. It emerged that the numerical modelling proposed enables an accurate prediction of the pore-water pressures under various hydraulic loadings
Modellazione statistica di valori estremi applicata ai volumi di laminazione generati con simulazioni continue di serie storiche
No full textNel presente lavoro si affronta il dimensionamento delle vasche di laminazione, con un approccio probabilistico, analizzando i dati di una serie storica di volumi, ottenuti tramite la simulazione continua di 16 anni di registrazioni pluviometriche della città di Bologna.
I dati ottenuti dal modello di simulazione sono stati analizzati ed adattati con diverse famiglie di modelli statistici, in particolare la famiglia GEV (Generalized Extreme Value) per i blocchi massimi, e la famiglia GPD (Generalized Pareto Distribution) per i dati estremi eccedenti una soglia. I modelli statistici ottenuti hanno permesso sia di quantificare i volumi di laminazione per vari tempi di ritorno, sia di quantificare l’incertezza su tali valori estremi.
E’ stato quindi utilizzato il metodo cinematico, prendendo in considerazione le formulazioni della Curva Possibilità Pluviometrica (CPP) oltre a quella tradizionale a due parametri (Alfonsi & Orsi, 1987), quella a due parametri doppia e tre parametri (Gottardi & Maglionico, 2006), per dimensionare gli invasi, per diversi tempi di ritorno, e confrontarli con i valori ottenuti dall’analisi statistica.
Dallo studio si rileva che le metodologie tradizionali basate sul metodo cinematico in generale sottostimano i volumi di laminazione rispetto ai valori ottenuti dai modelli probabilistici, pur rimanendo nella maggior parte dei casi all’interno delle fasce di confidenza al 95%. Tra i metodi tradizionali quello che presenta un miglior comportamento di stima, per tutti i tempi di ritorno indagati, è quello con rappresentazione della CPP a 3 parametri
Preface
No full textTen years after the successful conference held in Bari, the VI Italian Conference of Researchers in Geotechnical
Engineering (CNRIG) took place at the Auditorium of Department of Arts of the Alma Mater Studiorum in Bologna
on 22-23 September 2016. The event was organized by the Geotechnical Engineering Group of the University of
Bologna in collaboration with the National Group of Geotechnical Engineering (GNIG) and under the auspices of
the Department of Civil, Chemical, Environmental and Materials Engineering (DICAM) of the University of
Bologna. The overall theme of the Conference was "Geotechnical Engineering in Multidisciplinary Research: from
Microscale to Regional Scale", a purposely broad ‘hot’ topic that provided a wide scope for participation from the
many disciplines interacting on various issues with Geotechnical Engineering at different scales of analysis.
As tradition of such conferences which foster a lively debate on recent research advancements, the event
provided great opportunities for participants to share up-to-date knowledge, new ideas and experiences in
Geotechnical Engineering, as well as to discuss current research prospects and potential future collaborations
Experimental procedure for checking the saturation degree of piezocone tips
No full textA correct measurement of the water pore pressure is essential to obtain reliable CPT results. Although this has always been a major concern, it still remains a possible relevant source of error in common engineering practice. In addition to usual reasons, such as malfunctioning of the equipment, its poor calibration and/or maintenance, a lack of complete saturation of the piezocone tip can play a major role. In fact, a correct and timely pore pressure measurement relies entirely on the full saturation of the pore pressure system. The variety of saturation fluids and methods that is encountered in practice is a clear evidence of the still existing uncertainties on the most suitable procedure. Furthermore, unless the saturation process is explicitly detailed, its choice is typically left to the contractor and the measurement quality can only be established a posteriori, after the test has been completed. This paper describes a novel experimental equipment that enables quantifying the degree of saturation of the piezocone tip prior to testing. The methodology proposed is inspired to the B-value check, which is routinely used in geotechnical laboratory testing to assess the degree of saturation, e.g. prior to triaxial testing. In addition, it could also be applied after a test, so that it would be possible to assess whether saturation was retained while testing. This promising approach, when extended to different saturation procedures and validated by engineering practice, has the potential to become a relevant benchmark for reliable CPT testing
Reti nei servizi avanzati
No full textIl capitolo descrive un'indagine basata su due casi di studio nel settore dei servizi avanzati. Vengono illustrati i modelli emergenti di reti di impresa internazionali, e i relativi problemi di gestione degli scambi di conoscenza
Conclusioni
No full textIl capitolo riassume i risultati della vasta indagine sull'evoluzione dei modelli di impresa e delle reti di business internazionali condotta in diversi settori industriali e dei servizi
Quantitative modelling of spatial variability of piezocone data from Venice lagoon silty soils
No full textAs geotechnical research and design codes rely increasingly on probabilistic approaches, site characterization should also be conducted in the light of the explicit quantification of the uncertainty and spatial variability in soil properties. This paper provides a practical case-study application of spatial variability analysis of piezocone data obtained at a test site in the Lagoon surrounding the historic city of Venice, in North-Eastern Italy, where unusually dense and regularly spaced CPT test data were available. Empirical semivariograms are calculated for cone resistance, sleeve friction, and porewater pressure, along with the soil behavior classification index obtained from these measurements at a set of reference measurement depths. A number of theoretical semivariogram models are fitted comparatively and best-fit models are selected based on objective criteria and subjective judgment. Characteristic semivariogram parameters, providing information on correlation distance and small-scale variability, are retrieved. Modeling options are explained and results are analyzed and assessed critically
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