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Modoni, Giuseppe
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Modoni, Giuseppe
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- PublicationOpen AccessInsights into bedrock paleomorphology and linear dynamic soil properties of the Cassino intermontane basin (Central Italy)(2020)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Seismic amplifications are dictated by the depth of the bedrock and the stratigraphy and dynamic properties of the soil deposits. Quantifying these properties, together with their uncertainty, is a necessary task to perform a reliable assessment of the seismic risk at an urban scale. In this paper, a multidisciplinary analysis is presented, where information of different nature is combined. Borehole logs, geophysical, geological and geotechnical surveys are interpreted with the aid of analytical, numerical and geostatistical techniques to characterise the complex shape of the bedrock and the linear dynamic properties of the sedimentary deposits filling the Cassino basin, a Quaternary intermontane basin located in central Italy. The regional and local seismic hazard is firstly identified with geological surveys that reveal an active seismogenic fault capable of producing earthquakes with estimated magnitudes up to 6.5. Boreholes reaching depths variable up to a maximum of 180 meters and microtremor measurements, revealing the sharp impedance contrast at the transition between the sedimentary/arenaceous bedrock and the soft Quaternary infilling, are combined to identify the depth of the bedrock and the linear dynamic properties of soil deposits. These are one of the key factors governing the propagation to the ground level of seismic waves, and their assessment represents the first step for the seismic hazard characterisation of the plain.154 4 - PublicationRestrictedNew geological data on the Cassino intermontane basin, central Apennines, Italy(2014-10)
; ; ; ; ; ; ;Saroli, M.; Università degli Studi di Cassino e del Lazio Meridionale ;Lancia, M.; Università degli Studi di Cassino e del Lazio Meridionale ;Albano, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Modoni, G.; Università degli Studi di Cassino e del Lazio Meridionale ;Moro, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Scarascia Mugnozza, G.; Sapienza Università di Roma; ; ; ; ; This paper presents the outcome of photogeological analysis, field survey as well as borehole correlation, to add new data concerning the intermontane Cassino basin and define facies and thickness of its Quaternary deposits. The investigated area is located in the end sector of the Latina Valley, Southern Lazio and belongs to the Lazio–Abruzzi domain. With a maximum extension of 250 km2 and a NW–SE trend, this paleo-lake was created by lava flows from the Roccamonfina volcano, which barred the Latina Valley. The lacustrine facies were described during the 1960s but available bibliographic data about its spatial distribution and its relationship with the Mesozoic– Cenozoic bedrock are scarce. The thickness of Quaternary deposits has been deeply influenced by inherited paleomorphologies. Indeed the geological reconstruction of the basin has outlined the presence of an underlying horst and graben structure. This latter obscured the contractional tectonics originated by the orogenetic deformation, even if new structures have been recognized at the foot of Montecassino Hill. We infer that a key role has been per- formed by the Roveto Valley–Atina–Caserta fault, between Atina and San Pietro Infine.260 40 - PublicationRestrictedDetermination of the critical state of granular materials with triaxial tests(2017)
; ; ; ; ; ; ; ; ; While the Critical State Locus (CSL) determined from triaxial compression tests is commonly adopted for the constitutive modelling of soil, the validity of the locus for other stress paths needs to be proved. Several authors have tried to experimentally verify whether the classical CSL representation in the stress invariants - void ratio space could be considered as unique or should depend on the loading direction, but the question is still being debated and a unique conclusion has not been convincingly drawn. In order to clarify this issue, compression and extension triaxial tests are performed on granular materials with different characteristics, namely, two homogeneously distributed sands and an assembly of steel spheres prepared under different initial conditions. The procedure for identifying the CSL is reviewed and indicates the limitations arising from strain localization (shear bands and necking). All the tests show that the materials head to systematically different traces in the e-p' and p'. -q planes when sheared under triaxial compression and extension. Searching for the reasons for this phenomenon, small samples of sand are subjected to the same tests quantifying the whole strain field with X-ray tomography and a digital image correlation. This analysis reveals an inhomogeneous pattern of deformation that is strongly affected by the presence of the two rigid frictional bases and the flexible side membrane, even for the samples deforming in an apparently uniform manner. The different localization observed for the compression and extension tests justifies the dependence of the CSL on the stress path seen on the global scale. On the other hand, a unique trace of the CSL is obtained in the volumetric e-p' plane when the void ratio is measured limitedly to the zones affected by the largest distortion.94 8 - PublicationRestrictedCosesimic liquefaction phenomena from DInSAR after the May 20, 2012 Emilia earthquake(2015)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; In this paper, we have investigated the capability of Differential Interferometry Synthetic Aperture Radar (DInSAR) technique to detect the ground effects induced by liquefaction phenomena occurred during the May 20, 2012 Emilia earthquake. To this aim, a set of COSMO-SkyMed (CSK) SAR images covering the coseismic phase has been used. The detected surface effects have been related to liquefaction of deep sandy layers. Thanks to the geological/geotechnical data in the area and a liquefaction susceptibility analysis of the subsoil, it has been identified a sandy layer between 9 and 13 m in deep, which probably liquefied during the earthquake. The estimated vertical displacements due to liquefaction are comparable with the values measured by DInSAR.98 1 - PublicationRestrictedEffects of compaction on the seismic performance of embankments built with gravel(2018-08)
; ; ; ; ; ; ; The effects of compaction on the seismic performance of gravelly embankments is investigated transferring the precision of very accurate laboratory tests on the constituent material into the prediction of the large scale response. The stress-strain response observed upon monotonic and cyclic tests is captured by a critical state elastic-plastic model used as a virtual simulator of experiments to determine the influence of the initial state on the soil response. This dependency is introduced in equivalent linear elastic-perfectly plastic models as function of the state variable ψ to study the propagation of shear waves through horizontally layered landfills and em- bankments. A parametric analysis is performed assigning systematically variable seismic inputs, soil density and geometry to see the role of these factors on the soil response and the sliding resistance of the embankment. The study reveals an exceptionally high resistance of the gravel that enables embankment with steep abutments to resist against severe earthquakes.120 18 - PublicationRestrictedSeismic Microzonation of the Cassino PlainThanks to its favourable hydrogeological conditions, Cassino is one of the most studied sites of Central Italy. More than two hundred soil borings, some of them reaching depths as high as 100 m, have revealed a subsoil characterized by a calcareous platform and post-orogenetic series forming a tectonic basin filled by lacustrine and volcanic deposits. Together with the already available data, a number of geological, geotechnical and geophysical data have collected to study at a very detailed scale the seismic response of the site. Among them, a series of HVSR (horizontal to vertical spectral ratio) measurements have been performed to estimate the natural frequency of oscillation of the more deformable deposits. The combination of these data with the information given by the deep boreholes, permitted to rebuild the geological complexities of the tectonically driven seismic bedrock, outcropping continuously at east and west of the basin. This study forms the basis for mono, bi and three-dimensional numerical analyses aimed at predicting local amplification effects.
105 10 - PublicationRestrictedCoseismic liquefaction phenomenon analysis by COSMO-SkyMed : 2012 Emilia ( Italy ) earthquake(2015)
; ; ; ; ; ; ; ; ; ; ; ;Chini, M.; Luxembourg Institute of Science and Technology (LIST) ;Albano, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Saroli, M.; University of Cassino and Southern Lazio ;Pulvirenti, L.; CIMA Research Foundation ;Moro, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Bignami, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Falcucci, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Gori, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Modoni, G.; University of Cassino and Southern Lazio ;Pierdicca, N.; Sapienza University of Rome ;Stramondo, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;; ; ; ; ; ; ; ; ; The liquefaction phenomenon that occurred in the coseismic phase of th eMay 20,2012 Emilia(Italy) earthquake (ML5.9) is investigated. It was induced by the water pressure increase in the buried and confined sand layers.The level-ground liquefactionwastheresultofachaoticgroundoscillationcaused by theearthquakeshakingandtheobservedfailureswereduetotheupwardwaterflowcausedby the excessofporepressures.Weexploitedthecapabilityofthedifferentialsyntheticapertureradar interferometry (DInSAR)techniquetodetectsoilliquefactionsandestimatetheirsurfacedisplacements, as wellasthehighsensitivitytosurfacechangesofcomplexcoherence,SARbackscatteringandintensity correlation. Tothisaim,asetoffourCOSMO-SkyMedX-bandSARimages,coveringtheperiodApril 1–June 6,2012,wasused.Geological–geotechnicalanalysiswasalsoperformedinordertoascertainif the detectedSAR-basedsurfaceeffectscouldbeduetothecompactioninducedbyliquefactionofdeep sandy layers.Inthisregards,theresultsobtainedfrom13electricalconepenetrometertestsshowthe presence ofafinetomediumsandylayeratdepths,rangingbetween9and13m,whichprobablyliquefied during theearthquake,inducingverticaldisplacementsbetween3and16cm.Thequantitativeresults from geological–geotechnicalanalysisandthesurfacepunctualeffectsmeasuredbyDInSARareingood agreement, evenifsomedifferencesarepresent,probablyascribabletothelocalthicknessanddepth variability ofthesandylayer,ortolackofdeformationdetectionduetoDInSARdecorrelation.Theadopted approach permittedustodefinetheextentoftheareasthatunderwentliquefactionandtoquantifythe local subsidencerelatedtothesephenomena.Thelatterachievementprovidesusefulinformationthat must beconsideredinengineeringpractices,intermsofexpectedverticaldeformations.227 42 - PublicationRestrictedAssessment of the seismic performance of a bituminous faced rockfill dam(2015)
; ; ; ; ;Albano, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Modoni, G.; Università degli studi di Cassino e del Lazio meridionale ;Croce, P.; Università degli studi di Cassino e del Lazio meridionale ;Russo, G.; Università degli studi di Cassino e del Lazio meridionale; ; ; in the attempt to codify a procedure exportable to other similar cases, a thorough investigation of the seismic performance of a bituminous concrete faced rockfill dam built in Italy in the early eighties is herein presented. The dam presents a 90 m tall embankment built in a narrow canyon and is situated in a highly seismic region. The implemented methodology encompasses the indications provided by the most recent literature to point out the problems potentially caused by earthquakes and to account for the paramount factors affecting the response of the dam. Particular attention has been paid to the concept of performance, defining its goals in accordance with the most recent standards and deriving the correspondent limit conditions from observations reported in the literature. In order to optimize the computational effort, dynamic analyses with two and three dimensional finite difference codes have been combined to study the coupled response of the embankment, rocky foundation and bituminous facing. After validating the numerical models with centrifuge tests performed on small scale models of the embankment, the performance of the dam has been investigated with reference to a number of possible scenarios focusing 28 on the amplification spectra, the deformation of the embankment and the integrity of the bituminous lining.227 34