Deep tunnel fronts in cohesive soils under undrained conditions: a displacement-based approach for the design of fibreglass reinforcements     

di Prisco  Claudio  Flessati  Luca  Porta  Davide 《Acta Geotechnica》2020,15(4):1013-1030

The fronts of tunnels excavated under particularly difficult ground conditions by employing conventional tunnelling methods are commonly supported: the stabilization is usually achieved either by improving the mechanical properties of the soil (injections, jet grouting, soil freezing, etc.) or by introducing linear inclusions. This last technique, consisting in the introduction of pipes (usually made of fibreglass reinforced polymers) in the front, is particularly popular since it is very simple to adapt the reinforcement geometry, length and number to the different conditions encountered during the excavation. The design of this reinforcement technique is nowadays based on very simplified approaches: on either empirical formula or the limit equilibrium method. In a previous paper, the authors numerically studied the mechanical response of unreinforced fronts in cohesive soils and defined a non-dimensional front characteristic curve. In this paper, the authors intend to take into consideration the role of reinforcements by following the same approach. A procedure allowing the definition of the reinforced non-dimensional front characteristic curve, once the reinforcement pattern is assigned, is introduced. The practical use of this curve is described.

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Process-based design flood estimation in ungauged basins by conditioning model parameters on regional hydrological signatures     

Daniela Biondi  Davide Luciano De Luca 《Natural Hazards》2015,79(2):1015-1038

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Crystal structure refinement of chromites from two achondrites,their T‐f(O2) conditions,and implications          下载免费PDF全文

Davide Lenaz  Birger Schmitz 《Meteoritics & planetary science》2017,52(9):1763-1775

Six Cr‐spinel grains from NWA 6077 brachinite‐like and NWA 725 winonaite achondrites have been studied by single‐crystal X‐ray diffraction and structural refinement. From a chemical point of view, spinels from NWA 6077 show Cr/(Cr + Al) (i.e., Cr#) and Mg/(Mg + Fe²⁺) (i.e., Mg#) values similar to other brachinites, while the Cr# of NWA 725 is lower than that of literature winonaites. Spinels from NWA 6077 and NWA 725 meteorites show similar cell edges, while the oxygen positional parameter is rather different being about 0.2629 for NWA 6077 and 0.2622 for NWA 725. Considering both parameters, NWA 725 shows structural features that are close to some terrestrial spinel occurrences as in komatiites, kimberlites, or included in diamonds; those from NWA 6077 show values that have no terrestrial analogs. Olivine‐chromite closure temperature ranges from ~737 to ~765° C for NWA 725, being similar to that of literature winonaites and ~846 to ~884° C for NWA 6077. The logfO₂ ranges from ?19.8 to ?20.5 and ?17.0 to ?17.9 for the two meteorites, respectively. The u values for terrestrial samples can give information about the cooling history of the samples. For the extraterrestrial samples, it seems that it can give information about the cooling only for spinels where it is lower than 0.2625. For higher values, it appears related only to the chemistry of the spinels.  相似文献   

Coexisting tectonic settings: the example of the southern Tyrrhenian Sea     

Marco Cuffaro  Federica Riguzzi  Davide Scrocca  Carlo Doglioni 《International Journal of Earth Sciences》2011,100(8):1915-1924

We performed geodetic strain rate analyses in southern Italy, using new GPS velocities. Two-dimensional strain and rotation rate fields were estimated and results show that most of the shortening is distributed in the northern Sicily offshore. Extension becomes more evident and comparable with shortening on the eastern side of the same margin, and greater in the eastern Sicily offshore. Principal shortening and extension rate axes are consistent with long-term geological features: seismic reflection profiles show both active compressive and extensional faults affecting Pleistocene strata. We show evidence for contemporaneous extension and transtension in the Cefalù Basin. Combining geodetic data and geological features point to the coexistence of independent geodynamic processes, i.e., the active E–W backarc spreading in the hangingwall of the Apennines subduction zone and shortening along the southern margin of the Tyrrhenian backarc basin operated by the NNW-motion of Africa relative to Eurasia.  相似文献   

Human-induced coastal landslide reactivation. Monitoring by PSInSAR techniques and urban damage survey (SE Spain)   总被引：1，自引：1，他引：0  

Davide Notti  Jorge Pedro Galve  Rosa María Mateos  Oriol Monserrat  Francisco Lamas-Fernández  Francisca Fernández-Chacón  Francisco Javier Roldán-García  José Vicente Pérez-Peña  Michele Crosetto  José Miguel Azañón 《Landslides》2015,12(5):1007-1014

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Georeferencing Animal Specimen Datasets          下载免费PDF全文

Marieke van Erp  Robert Hensel  Davide Ceolin  Marian van der Meij 《Transactions in GIS》2015,19(4):563-581

For biodiversity research, the field of study that is concerned with the richness of species of our planet, it is of the utmost importance that the location of an animal specimen find is known with high precision. Due to specimens often having been collected over the course of many years, their accompanying geographical data is often ambiguous or may be very imprecise. In this article, we detail an approach that utilizes reasoning and external sources to improve the geographical information of animal finds. Our main contribution is to show that adding external domain knowledge improves the ability to georeference locations over traditional methods that focus solely on analyzing geographical information. Additionally, our system is able to output the confidence it has in its decisions through a confidence measure based on the difficulty of the instance and the steps undertaken to disambiguate it. Our results show that adding domain knowledge to the georeferencing process increases the accuracy @5km from 38.9% to 61.7% and from 47.0% to 74.5% @25km. Furthermore, we reduce the mean distance by more than half, from 251.1km to 114.5km, and decrease the number of records for which no reference can be found from 26.2% to 7.4%.  相似文献   

New results on ground deformation in the Upper Silesian Coal Basin (southern Poland) obtained during the DORIS Project (EU-FP 7)     

Marek Graniczny  Davide Colombo  Zbigniew Kowalski  Maria Przyłucka  Albin Zdanowski 《Pure and Applied Geophysics》2015,172(11):3029-3042

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Long-term model of planimetric and bathymetric evolution of a tidal lagoon     

Giampaolo Di Silvio  Chiara Dall’Angelo  Davide Bonaldo  Giacomo Fasolato 《Continental Shelf Research》2010

This model is based on the concept of transport concentration, defined as the time-averaged concentration in a given location of a lagoon, which determines the long-term net transport of sediments as the sum of a dispersive and an advective flux. Dispersive net flux of sediments is due to the alternate components of the tidal flow, while the advective net flux of sediments is due to the residual (Eulerian) component of the tidal, fluvial and littoral flow and possibly to the asymmetry between flow and ebb tide.  相似文献   

Reliability of the automatic procedures for locating earthquakes in southwestern Alps and northern Apennines (Italy)     

Chiara Turino  Paola Morasca  Gabriele Ferretti  Davide Scafidi  Daniele Spallarossa 《Journal of Seismology》2010,14(2):393-411

Reliable automatic procedure for locating earthquake in quasi-real time is strongly needed for seismic warning system, earthquake preparedness, and producing shaking maps. The reliability of an automatic location algorithm is influenced by several factors such as errors in picking seismic phases, network geometry, and velocity model uncertainties. The main purpose of this work is to investigate the performances of different automatic procedures to choose the most suitable one to be applied for the quasi-real-time earthquake locations in northwestern Italy. The reliability of two automatic-picking algorithms (one based on the Characteristic Function (CF) analysis, CF picker, and the other one based on the Akaike’s information criterion (AIC), AIC picker) and two location methods (“Hypoellipse” and “NonLinLoc” codes) is analysed by comparing the automatically determined hypocentral coordinates with reference ones. Reference locations are computed by the “Hypoellipse” code considering manually revised data and tested using quarry blasts. The comparison is made on a dataset composed by 575 seismic events for the period 2000–2007 as recorded by the Regional Seismic network of Northwestern Italy. For P phases, similar results, in terms of both amount of detected picks and magnitude of travel time differences with respect to manual picks, are obtained applying the AIC and the CF picker; on the contrary, for S phases, the AIC picker seems to provide a significant greater number of readings than the CF picker. Furthermore, the “NonLinLoc” software (applied to a 3D velocity model) is proved to be more reliable than the “Hypoellipse” code (applied to layered 1D velocity models), leading to more reliable automatic locations also when outliers (wrong picks) are present.  相似文献   

Implementation of the European Water Framework Directive: Natural variability associated with the CARLIT method on the rocky shores of the Ligurian Sea (Italy)     

Valentina Asnaghi  Mariachiara Chiantore  Rosa‐Maria Bertolotto  Valeriano Parravicini  Riccardo Cattaneo‐Vietti  Federico Gaino  Paolo Moretto  Davide Privitera  Luisa Mangialajo 《Marine Ecology》2009,30(4):505-513

The Water Framework Directive (WFD) 2000/60/EC, adopted by the European Community in 2000 with the goal of maintaining and improving the aquatic environments, requires that member states achieve and maintain a good ecological status of all water bodies by 2015. In the marine context, the ecological status has to be quantified applying indexes based on appropriate key biological elements, which allow the categorization of water bodies into five Ecological Status (ES) classes. The CARLIT index is a cartographic monitoring tool enabling the Ecological Quality Ratio (EQR) to be calculated using macroalgae in coastal hard bottoms as a key biological element; at present it is being applied in Spain, France and Italy. To detect actual changes of water quality and, consequently, rely on the application of indexes for the assessment of the ecological status in the marine environment, it is necessary to evaluate their sensitivity to natural variability at different temporal and spatial scales. In this study we present a first quantification of natural (spatial and temporal) variability of EQR‐CARLIT quality assessment in 2006 and 2007 along the Ligurian coast (North‐Western Mediterranean, Italy). The EQR‐CARLIT values recorded along the Ligurian coastline show that natural variability of EQR‐CARLIT is low and that it does not affect the attribution of a given stretch of coast to a particular ES class, in agreement with the major human pressures acting in the area (urbanization, river load, sea‐farming). A small‐scale variability was detected, strengthening the use of cartography of the whole rocky shore, whenever possible, or, alternatively, the assessment of the ecological status for long stretches of coast, to encompass the small‐scale variability due to local factors.  相似文献