876 research outputs found
The defense of the city of Venice and of the lagoonal ecosystem: an ongoing challenge for geotechnical engineering|La difesa della città di Venezia e dell’ecosistema lagunare: una sfida continua per l’ingegneria geotecnica
No full textThe worldwide-known historic city of Venice continues to preserve a rather precarious equilibrium with the surrounding lagoon, although the margin of security is being eroded at increasing rate. The rate of environmental deterioration is being accelerated by the increasing frequency of the flooding of the historic city and surrounding lagoon caused by the natural eustatic rise of the sea level, by natural subsidence and by a regional man-induced subsidence, the latter particularly important in the last century. The paper, based on the Croce Conference given in Rome on the 16 December 2021, emphasizes the relevant role of geotechnical engineering, and especially site and laboratory investigations, monitoring, data analysis and interpretation and modelling of fundamental geotechnical issues for the preservation of city and surrounding lagoon
Geotechnics of Venice and Its Lagoon
No full textWithout any protective intervention, the historic city of Venice and its surrounding islands would suffer rapid deterioration due to the increased frequency of tidal flooding, as the gap between land surface and sea levels has reduced due to a coupled effect of climate change-induced sea-level rise and natural and anthropic subsidence. Geotechnics of Venice and Its Lagoon provides a clear and comprehensive illustration of the extensive geotechnical aspects of not only the various environmental problems such as land subsidence and wetland surface reduction, but also solutions such as the design of the tilting gate foundations against high tides and the restoration and improvement of the drainage system of the renowned Piazza San Marco, which have been necessary for the preservation of the extraordinary cultural heritage of Venice. Readers will gain a better understanding of the complex phenomena occurring in the sensitive Venice silts, whose hydro-mechanical behavior has required compre..
Podocampa simonini Conde 1956
No full textPodocampa simonini Condé, 1956 Podocampa simonini Condé, 1956a: 31. Diagnosis (Condé 1956a, 1982b; Sendra 1988) Body length 6.5–9 mm; middle-sized, smooth clothing setae; protruding frontal process; antennae with 58–64 antennomeres; sensillum of third antennomere in ventral position; cupuliform organ with eight complex olfactory chemoreceptors; long, curved gubia sensilla; long notal macrosetae with barbs along distal two thirds; long marginal setae with barbs along distal half; two or three ventral tibial macrosetae; calcars with a few barbs along distal half; smooth subapical tarsal setae; setiform smooth telotarsal process; 1+1 lp on IV urotergite, 1+1 la, 2+2 lp on V–VII urotergites, 1+1 mp, 3+3 lp on VIII urotergite, 1+1 mp 5+5 lp on IX abdominal segment; first male urosternite without glandular g1 -setae, subtrapezoidal appendages with glandular a 1 and a 2 setae; cerci three times as long as body with up to 20 articles covered in long, barbed macrosetae and short, smooth cloting setae; spermatozoid fascicles 70 μm in diameter. Habitat and distribution Cave-dwelling species known from several caves in the Basque Mountains, northern Iberian Peninsula (Condé, 1956a, 1982b).Published as part of Sendra, Alberto & Reboleira, Ana Sofia P. S., 2020, Euro-Mediterranean fauna of Campodeinae (Campodeidae, Diplura), pp. 1-130 in European Journal of Taxonomy 728 on pages 113-114, DOI: 10.5852/ejt.2020.728.1181, http://zenodo.org/record/431688
Resistenza dei materiali nell'analisi di stabilità di un ammasso di rifiuti solidi urbani.
No full textRilevati e argini
No full textLa progettazione e costruzione di rilevati stradali, ferroviari ed arginali, e più in generale delle opere in materiali sciolti, già oggetto di interventi normativi di carattere nazionale, è trattata dettagliatamente nell’ Eurocodice 7 - Parte 1 e, per gli aspetti sismici, nell’Eurocodice 8 - Parte 5. Dopo un breve riepilogo delle problematiche attinenti a tali manufatti, la presente nota analizza e commenta gli argomenti trattati nell’EC7 e nell’EC8 relativamente agli argini ed ai rilevati, proponendo anche un confronto con le disposizioni della Normativa Italiana
Evaluation of secondary compression of sands and silts from CPTU
No full textThe estimate of secondary compression behaviour of sandy and silty deposits is not routinely taken into account in the classical settlement calculation, due to its generally limited contribution to the total amount of strains. However, such soils exhibit a non-negligible time-dependent behaviour and the prediction of their long-term response may sometimes be important.
This paper explores the capability of the piezocone test as an effective tool to estimate the one-dimensional secondary compression characteristics of sands and silts. The approach is mainly based on the observation that frictional response essentially governs both secondary compression of granular soils and cone resistance, hence it seems reasonable to establish a valid correlation among them.
The study uses part of the field data assembled over the last years at the Treporti Test Site (Venice, Italy), within an extensive research project aimed at analysing the stress-strain-time response of the predominantly silty sediments forming the Venetian lagoon subsoil.
Empirical, site-specific correlations for estimating the secondary compression coefficient from cone resistance are proposed. The regression analyses indicate that the estimate is slightly improved if the cone resistance-based correlations include a variable accounting for the different pore pressure response associated to the drainage conditions around the advancing cone
Behaviour of a Pre-loading Embankment on Soft Cohesive Soil.
No full textThe bahaviour overt time of the foundation soil under a preloading embankment is modelled using the finite element method, showing the importance of in situ testing for the determination of soil propertie
Investigation and monitoring to model the interaction between the Scrovegni’s Chapel in Padova (Italy) and the underlying foundation soil
No full textIn Padova's historic centre lies the renowned Scrovegni’s Chapel, painted by Giotto in 1303. The local subsoil primarily consists of silty sand with some layers of silt. The crypt beneath acts as a buffer against soil moisture, preventing damage to the frescoes. However, during heavy rain, groundwater rises flowing across the floor and lateral walls, therefore flooding the pavement. A pumping system is eventually activated to mitigate the pavement inundation. Several investigations including geophysical surveys, piezocone tests, and boreholes with soil sampling have been conducted to provide the subsoil geotechnical model and understand the local hydrogeological behaviour. Monitoring systems, such as piezometers, deep extensometers and optical fiber cables, track groundwater levels and long-term soil displacements.
The paper aims to characterize the subsoil's stratigraphy, mechanical properties and permeabilities to model how the environmental conditions affect the ancient Chapel and ensure its long-term stability
Primary and secondary compression characteristics of silts from CPTU: lessons learnt from the Venetian lagoon sediments
No full textThis paper explores the capability of cone penetration (CPT/CPTU) as an effective tool to estimate primary and secondary compression coefficients in silts, silt mixtures and sand mixtures. The study uses, as a reference database, part of the large amount of CPTU data and subsoil deformation measurements assembled over the last years at the Treporti Test Site (Venice, Italy), within an extensive research project aimed at thoroughly analyzing the stress-strain-time response of the complex assortment of sandy and silty sediments forming the Venetian lagoon subsoil. The development of CPTU-based empirical correlations, providing reliable estimate of the compressibility characteristics of such intermediate soils, may be very useful for geotechnical practice in the Venetian lagoon area or similar depositional environments, since undisturbed sampling of these sediments is very difficult to achieve and geotechnical characterization of this deposits must essentially rely on in situ testing
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