Shear strength of a compacted scaly clay in variable saturation conditions     

Marco?Rosone  Camillo?Airò Farulla  Alessio?FerrariEmail author 《Acta Geotechnica》2016,11(1):37-50

Scaly clays are stiff and highly fissured clays often used as construction materials. This paper presents the results of triaxial compression tests carried out on saturated and unsaturated samples of a compacted scaly clay. Complementary investigation on the microstructural features and their evolution with the amount of water stored into the material are also presented in order to shed light on the evolution of the micro- and macroporosity with suction. The water retention behaviour of the compacted scaly clay is also addressed. The results from the controlled suction triaxial tests are used to discuss the applicability of a single-shear strength criterion to compacted double-structured clays when the effective stress concept for unsaturated soils is used. The choice of the degree of saturation to be included in the effective stress definition for obtaining a satisfactory representation of the shear strength is addressed. It is shown that the best results are obtained when the macropore degree of saturation is considered along with its evolution during the applied stress path.  相似文献   

Erratum to: The environmental effects of the 1743 Salento earthquake (Apulia,southern Italy): a contribution to seismic hazard assessment of the Salento Peninsula     

Nappi  R.  Gaudiosi  G.  Alessio  G.  De Lucia  M.  Porfido  S. 《Natural Hazards》2016,86(2):295-324

The aim of this study was to provide a contribution to seismic hazard assessment of the Salento Peninsula (Apulia, southern Italy). It is well known that this area was struck by the February 20, 1743, earthquake (I ₀ = IX and M _w = 7.1), the strongest seismic event of Salento, that caused the most severe damage in the towns of Nardò (Lecce) and Francavilla Fontana (Brindisi), in the Ionian Islands (Greece) and in the western coast of Albania. It was also widely felt in the western coast of Greece, in Malta Islands, in southern Italy and in some localities of central and northern Italy. Moreover, the area of the Salento Peninsula has also been hit by several low-energy and a few high-energy earthquakes over the last centuries; the instrumental recent seismicity is mainly concentrated in the western sector of the peninsula and in the Otranto Channel. The Salento area has also experienced destructive seismicity of neighboring regions in Italy (the Gargano Promontory in northern Apulia, the Southern Apennines chain, the Calabrian Arc) and in the Balkan Peninsula (Greece and Albania). Accordingly, a critical analysis of several documentary and historical sources, as well as of the geologic–geomorphologic ground effects due to the strong 1743 Salento earthquake, has been carried out by the authors in this paper; the final purpose has been to re-evaluate the 1743 MCS macroseismic intensities and to provide a list of newly classified localities according to the ESI-07 scale on the base of recognized Earthquake Environmental Effects. The result is a quite different damage scenario due to this earthquake that could raise the seismic potential currently recognized for the Salento area, and consequently upgrade the seismic hazard classification of the Salento. Indeed it is important to remind that currently, despite the intense earthquake activity recorded not only in the Otranto Channel, but especially in Greece and Albania, this area is classified in the least dangerous category of the Seismic Classification of the Italian territory (IV category).

  相似文献   

Projections of extreme storm surge levels along Europe     

Michalis I. Vousdoukas  Evangelos Voukouvalas  Alessandro Annunziato  Alessio Giardino  Luc Feyen 《Climate Dynamics》2016,47(9-10):3171-3190

  相似文献   

Biostratigraphy of large benthic foraminifera from Hole U1468A (Maldives): a CT-scan taxonomic approach     

Giovanni Coletti  Stephanie Stainbank  Alessio Fabbrini  Silvia Spezzaferri  Anneleen Foubert  Dick Kroon  Christian Betzler 《Swiss Journal of Geoscience》2018,111(3):523-536

Large benthic foraminifera are important components of tropical shallow water carbonates. Their structure, developed to host algal symbionts, can be extremely elaborate and presents stratigraphically-significant evolutionary patterns. Therefore their distribution is important in biostratigraphy, especially in the Indo-Pacific area. To provide a reliable age model for two intervals of IODP Hole U1468A from the Maldives Inner-Sea, large benthic foraminifera have been studied with computed tomography. This technique provided 3D models ideal for biometric-based identifications, allowing the upper interval to be placed in the late middle-Miocene and the lower interval in the late Oligocene.  相似文献   

Distinctive Volcanic Material for the Production of Campana A Ware: The Workshop Area of Neapolis at the Duomo Metro Station in Naples,Italy     

Alberto De Bonis  Stefania Febbraro  Chiara Germinario  Daniela Giampaola  Celestino Grifa  Vincenza Guarino  Alessio Langella  Vincenzo Morra 《Geoarchaeology》2016,31(6):437-466

Recent transportation infrastructure works in Naples, Italy, provided important discoveries related to the production of pottery in the Hellenistic workshop area of Piazza Nicola Amore. A minero‐petrographic investigation was conducted on 35 samples belonging to the widespread Campana A ware and production indicators (clayey raw materials, unfired Graeco‐Italic amphorae, kiln wastes, workshop tools). Additional analysis was conducted on black‐glaze and common ware samples for comparison. The analyses reveal compositional and technological homogeneity of Campana A ware. Samples are characterized by low CaO content with evidence of both volcanic and sedimentary components, suggesting that different clay sources were properly mixed to prepare a standard recipe. Production indicators, black‐glaze and common wares, have a composition well consistent with the calcareous clays from the island of Ischia. Leucite‐ and garnet‐bearing temper from the Somma Volcano were used for the preparation of coarse‐grained pastes, unfired Graeco‐Italic amphorae, and clayey raw materials, thus suggesting that they represented the clay sources for amphorae production. Our results reveal new technological and socioeconomic aspects of Hellenistic pottery production in the Bay of Naples, in particular for the Campana A ware, now representing a new reference group: Neapolis.  相似文献   

Cost–benefit analysis of flood mitigation measures: a case study employing high-performance hydraulic and damage modelling     

Molinari  Daniela  Dazzi  Susanna  Gattai  Edoardo  Minucci  Guido  Pesaro  Giulia  Radice  Alessio  Vacondio  Renato 《Natural Hazards》2021,108(3):3061-3084

Natural Hazards - This paper shows a detailed, advanced procedure to implement cost–benefit analyses (CBAs) in order to assess the effectiveness of flood mitigation measures. The town of Lodi...  相似文献   

Role of melting process and melt–rock reaction in the formation of Jurassic MORB-type basalts (Alpine ophiolites)     

Maria?Rosaria?RennaEmail authorView author&#;s OrcID profile  Riccardo?Tribuzio  Alessio?Sanfilippo  Matthew?Thirlwall 《Contributions to Mineralogy and Petrology》2018,173(4):31

This study reports a geochemical investigation of two thick basalt sequences, exposed in the Bracco–Levanto ophiolite (northern Apennine, Italy) and in the Balagne ophiolite (central-northern Corsica, France). These ophiolites are considered to represent an oceanward and a continent-near paleogeographic domain of the Jurassic Liguria–Piedmont basin. Trace elements and Nd isotopic compositions were examined to obtain information about: (1) mantle source and melting process and (2) melt–rock reactions during basalt ascent. Whole-rock analyses revealed that the Balagne basalts are slightly enriched in LREE, Nb, and Ta with respect to the Bracco–Levanto counterparts. These variations are paralleled by clinopyroxene chemistry. In particular, clinopyroxene from the Balagne basalts has higher Ce_N/Sm_N (0.4–0.3 vs. 0.2) and Zr_N/Y_N (0.9–0.6 vs. 0.4–0.3) than that from the Bracco–Levanto basalts. The basalts from the two ophiolites have homogeneous initial Nd isotopic compositions (initial ε_Nd from +?8.8 to +?8.6), within typical depleted mantle values, thereby excluding an origin from a lithospheric mantle source. These data also reject the involvement of contaminant crustal material, as associated continent-derived clastic sediments and radiolarian cherts have a highly radiogenic Nd isotopic fingerprint (ε_Nd at the time of basalt formation?=???5.5 and ??5.2, respectively). We propose that the Bracco–Levanto and the Balagne basalts formed by partial melts of a depleted mantle source, most likely containing a garnet-bearing enriched component. The decoupling between incompatible elements and Nd isotopic signature can be explained either by different degrees of partial melting of a similar asthenospheric source or by reaction of the ascending melts with a lower crustal crystal mush. Both hypotheses are reconcilable with the formation of these two basalt sequences in different domains of a nascent oceanic basin.  相似文献   

A multi-model comparison of Atlantic multidecadal variability     

Jin Ba  Noel S. Keenlyside  Mojib Latif  Wonsun Park  Hui Ding  Katja Lohmann  Juliette Mignot  Matthew Menary  Odd Helge Otterå  Bert Wouters  David Salas y Melia  Akira Oka  Alessio Bellucci  Evgeny Volodin 《Climate Dynamics》2014,43(9-10):2333-2348

A multi-model analysis of Atlantic multidecadal variability is performed with the following aims: to investigate the similarities to observations; to assess the strength and relative importance of the different elements of the mechanism proposed by Delworth et al. (J Clim 6:1993–2011, 1993) (hereafter D93) among coupled general circulation models (CGCMs); and to relate model differences to mean systematic error. The analysis is performed with long control simulations from ten CGCMs, with lengths ranging between 500 and 3600 years. In most models the variations of sea surface temperature (SST) averaged over North Atlantic show considerable power on multidecadal time scales, but with different periodicity. The SST variations are largest in the mid-latitude region, consistent with the short instrumental record. Despite large differences in model configurations, we find quite some consistency among the models in terms of processes. In eight of the ten models the mid-latitude SST variations are significantly correlated with fluctuations in the Atlantic meridional overturning circulation (AMOC), suggesting a link to northward heat transport changes. Consistent with this link, the three models with the weakest AMOC have the largest cold SST bias in the North Atlantic. There is no linear relationship on decadal timescales between AMOC and North Atlantic Oscillation in the models. Analysis of the key elements of the D93 mechanisms revealed the following: Most models present strong evidence that high-latitude winter mixing precede AMOC changes. However, the regions of wintertime convection differ among models. In most models salinity-induced density anomalies in the convective region tend to lead AMOC, while temperature-induced density anomalies lead AMOC only in one model. However, analysis shows that salinity may play an overly important role in most models, because of cold temperature biases in their relevant convective regions. In most models subpolar gyre variations tend to lead AMOC changes, and this relation is strong in more than half of the models.  相似文献   

The Space and Time Features of Global SST Anomalies Studied by Complex Principal Component Analysis     

Silvia Alessio  Arnaldo Longhetto  Luo Meixia 《大气科学进展》1999,16(1):1-23

１ＩｎｔｒｏｄｕｃｔｉｏｎＰｒｉｎｃｉｐａｌｃｏｍｐｏｎｅｎｔａｎａｌｙｓｉｓｈａｓｂｅｅｎｗｉｄｅｌｙｕｓｅｄｔｏｓｔｕｄｙｔｈｅｔｅｍｐｏｒａｌａｎｄｓｐａｔｉａｌｂｅｈａｖｉｏｕｒｏｆａｔｍｏｓｐｈｅｒｉｃａｎｄｏｃｅａｎｉｃｆｉｅｌｄｓ．...  相似文献   

Testing a new rill flow resistance approach using the Water Erosion Prediction Project experimental database     

Alessio Nicosia  Costanza Di Stefano  Vincenzo Pampalone  Vincenzo Palmeri  Vito Ferro  Mark A. Nearing 《水文研究》2019,33(4):616-626

In this paper, a recently theoretically deduced rill flow resistance equation, based on a power‐velocity profile, was tested using the Water Erosion Prediction Project database. This database includes measurements of flow velocity, water depth, cross section area, wetted perimeter, and bed slope that were made in rills shaped on experimental sites distributed across the continental United States. In particular, three different experimental conditions (only rainfall, only flow, and rain with flow) were examined, and for each condition, the theoretically based relationship for estimating the Γ function of the power velocity profile was calibrated. The results established that (a) the Darcy‐Weisbach friction factor can be accurately estimated using the proposed theoretical approach, and (b) the flow resistance increases with the effect of rainfall impact.  相似文献