Options
Madiai, Claudia
Loading...
Preferred name
Madiai, Claudia
4 results
Now showing 1 - 4 of 4
- PublicationRestrictedDynamic characterization of fine-grained soils in Central Italy by laboratory testing(2020)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; The investigation of soil response to dynamic loads is necessary to predict site-specific seismic hazard. This paper presents the results of cyclic and dynamic laboratory tests carried out after the 2016–2017 Central Italy Earthquake sequence, within the framework of the seismic microzonation studies of the most damaged municipalities in the area. The database consists of 79 samples investigated by means of dynamic resonant column tests, cyclic torsional shear tests or cyclic direct simple shear tests. Results are firstly analysed in terms of field and laboratory values of small-strain shear wave velocity, highlighting the influence of the sample disturbance and of the mean effective consolidation pressure. The cyclic threshold shear strains as a function of plasticity index are then compared with findings from the published literature and the outliers are analysed. Subsequently, the dynamic soil behaviour is investigated with reference to the small-strain damping ratio. Differences between results from different tests are analysed in the light of the loading frequencies. Finally, the database is used to develop a predictive model for soil nonlinear curves according to plasticity index, mean effective confining stress, and loading frequency. The model represents a useful tool to predict the nonlinear stress–strain behaviour of Central Italy soils, necessary to perform site-specific ground response analyses.70 2 - PublicationRestrictedGeotechnical characterization of the aterno valley for site response analyses(2013)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ;The paper reports about the in-situ and laboratory tests executed in the aftermath of the April 6, 2009 L’Aquila earthquake, aimed at contributing to the definition of geotechnical models for site response analyses in the Aterno valley. The investigation started immediately after the earthquake and was entrusted by the Civil Protection Department to different public institutions and private companies; the experimental activities here reported were coordinated by the Italian Geotechnical Society. In the paper, after briefly depicting the geological setting of the L’Aquila basin and the Aterno river valley, an overview of their subsoil conditions is given, based on the geotechnical tests executed before the 2009 earthquake. Thereafter, the specific investigations planned for the characterization of reconstruction sites and seismic microzonation are widely described. The in situ tests consisted of seismic dilatometer and multi-receiver surface wave tests; the resulting shear wave velocity profiles were compared each other, and against independent Down-Hole tests and ambient noise measurements. The laboratory investigation included cyclic/dynamic simple/torsional shear tests on undisturbed samples. The results, summarized in terms of variation of stiffness and damping with shear strain, highlighted some peculiar properties of the soils in the Aterno valley, which could be related to their index properties.147 4 - PublicationOpen AccessInterpreting the deformation phenomena triggered by the 2012 Emilia seismic sequence on the Canale Diversivo di Burana banks(2015)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;L’ articolo descrive uno studio riguardante i fenomeni deformativi osservati dopo il sisma dell’Emilia del maggio 2012 lungo un tratto di argine del Canale Diversivo di Burana che ricade nell’abitato di Scortichino, frazione del comune di Bondeno (FE). In questa porzione del rilevato arginale sono state edificate oltre un centinaio di abitazioni ed alcune strutture di medio-piccole dimensioni adibite ad attività produttive o a deposito, molte delle quali sono risultate pesantemente danneggiate e dichiarate inagibili proprio a causa delle deformazioni e del sistema di fratture longitudinali presenti nel terreno in seguito al terremoto. Il contributo qui presentato si prefigge di analizzare la risposta sismica dell’argine durante la sequenza sismica del 2012, comprendere le cause dei dissesti nonché individuare le necessarie azioni di mitigazione e gli eventuali interventi di messa in sicurezza nei confronti di terremoti futuri. A questo scopo è stata condotta un’ampia campagna sperimentale di indagini in sito e in laboratorio, finalizzata alla ricostruzione di un accurato modello geotecnico per la valutazione delle condizioni di stabilità dell’argine in condizioni sismiche, portando in conto anche l’eventuale insorgenza di fenomeni di liquefazione nei terreni sabbiosi superficiali costituenti la fondazione del corpo arginale. L’ analisi illustrata è il risultato dell’attività di indagine svolta per più di un anno dal Gruppo di Lavoro Argini (GdLA), costituitosi nel luglio 2012 in seguito ad un accordo fra la Regione Emilia-Romagna e l’Associazione Geotecnica Italiana per la verifica delle condizioni di stabilità dei rilevati arginali nelle aree colpite dal terremoto.193 137 - PublicationOpen AccessThe first Italian blast-induced liquefaction test (Mirabello, Emilia-Romagna, Italy): description of the experiment and preliminary results(2017)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ;; ; ;; ; ;; ; ; ; ;; ; ; ; ; ; ; ; ; ; ; ;; ;; ; ; ; ;; ;; Soil liquefaction can result in significant settlement and reduction of load-bearing capacity. Moreover, the generation of pore pressure during an earthquake and its post-seismic dissipation can generate permanent deformations and settlements. The quantitative evaluation of post-liquefaction settlements is of extreme importance for engineering purposes, i.e. for earthquake-resistant design of new buildings and safety evaluation of existing ones. Quantifying the extent of these phenomena is, however, rather difficult. Uncertainties arise from the stochastic nature of the earthquake loading, from the simplifications of soil models, and from the difficulty in establishing correlations between the pre-earthquake soil state and the post-seismic deformations. Field scale liquefaction tests, under controlled conditions, are therefore important for a correct quantification of these phenomena. Recent experiences (e.g. New Zealand, United States) show that liquefaction can be induced and monitored with field scale blast tests to study the related effects on soil geotechnical properties. Within this framework this paper introduces the preliminary results obtained from a research project on blast-induced liquefaction at field scale. Tests were performed at a trial site located in Mirabello (Ferrara, Italy), a village strongly affected by liquefaction phenomena during the 2012 Emilia Romagna earthquake. Invasive tests, such as piezocone, seismic dilatometer and down-hole tests, and non-invasive tests were carried out before and after the execution of two blast test sequences to study the variation in physical properties of the soils. Pore pressure transducers, settlement profilometers and accelerometers were installed with the objective of measuring, during and after the detonations, the generation and subsequent dissipation of the pore pressure, the vertical deformations, and the blast-induced ground motions respectively. Variations in load distribution on deep foundations due to soil liquefaction were also evaluated on a test micropile instrumented with a strain gauge array. Topographical surveys were carried out to measure ground surface settlements. Laboratory tests and trenches also provided increased understanding of the site characteristics.1685 138