Mirko Marracci, Alessandro Sbrana, Michele Sbrana, Bernardo Tellini
This paper explores the measurements of subsoil parameters in geothermal heat pump systems located in historical centers. A closed loop geothermal system serves the heating and cooling requirements of a wing of the Grand Duke historic Palace in the old town district of Pisa. The subsoil temperatures are measured at different depths and positions around the closed loop probes to investigate the thermal diffusion in the subsoil. Water flows, electrical power, flow and return temperatures and other plant data are analyzed to study the geothermal plant energy behavior during the operation.
TC4 International Workshop on Metrology for Geotechnics 2016
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· 2016
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Augusto Penna, Gianmario Sorrentino, Alessandro Flora, Armando Lucio Simonelli
The paper presents the results of laboratory tests carried out on undisturbed specimens of a gravelly soil sampled by in situ freezing. Because of the heterogeneity of the natural deposit, the grain size distribution of the specimens ranged from uniform sand with a very low percentage of gravel to wellgraded sandy gravel, and three different soil groups could be defined according to grain size (respectively named A, B and C). The testing programme comprised drained and undrained monotonic triaxial tests and undrained cyclic triaxial tests, carried out on both isotropically and...
TC4 International Workshop on Metrology for Geotechnics 2016
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Augusto Penna, Gianmario Sorrentino, Anna d’Onofrio, Francesco Silvestri, Armando Lucio Simonelli
The dynamic response of cantilever retaining walls under seismic actions was studied by means of 1-g shaking table at the Earthquake and Large Structures Laboratory (EQUALS) which is part of the Bristol Laboratories of Advanced Dynamics Engineering (BLADE), of the University of Bristol. The soil material used to build the geotechnical model consists of dry, yellow Leighton Buzzard (LB) Fraction B. This soil has been used extensively in experimental researches on shaking table. However, no information on the dynamic behaviour at low confining stress is available for this soil. To fill this...
TC4 International Workshop on Metrology for Geotechnics 2016
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· 2016
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Daniela Dominica Porcino, Valentina Diano
Owing to some peculiar properties of “unusual” calcareous sands, most of which is linked to grain crushability, an accurate evaluation of liquefaction resistance (CRR) of such sediments requires the development of new soil-type specific relationships. An experimental laboratory study based on undrained cyclic simple shear (SS) tests and bender element (BE) tests in triaxial apparatus was performed on a biogenic uncemented carbonate sand, Quiou sand, dug out from a site close to Plouasne (Brittany region, France), in order to seek a relationship between CRR and normalized shear wave velocity...
TC4 International Workshop on Metrology for Geotechnics 2016
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· 2016
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Sha Luo, Andrea Diambra, Erdin Ibraim
When the confining pressure is sufficiently large, soil grain breakage can occur and this can have a significant influence on the performance of a wide range of geotechnical systems such as shallow foundations, embankments and dams, railway substructures. However, the mechanics of particle crushing still remains one of the most difficult problems in geomechanics, while the link between the breakage of particles and the mechanical response of the soil through adequate continuum constitutive models has not been solved satisfactorily. This study investigates the possibility of using Acoustic...
TC4 International Workshop on Metrology for Geotechnics 2016
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Giovanni Biondi, Paola Capilleri, Ernesto Motta
The seismic performance of retaining walls is usually evaluated through simplified displacementbased approaches which neglect the change in the soilwall system geometry as displacements develop. In this vein, the paper describes the results of several shaking table tests carried out on a reduced-scale model of a retaining wall placed inside a flexible soil container and subjected to harmonic input motions. In the paper the permanent displacements of the wall and of the retained soil were presented and compared with numerical predictions obtained using a modified Newmark-type model, which...
TC4 International Workshop on Metrology for Geotechnics 2016
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Alessandro Mandolini, Andrea Diambra, Erdin Ibraim
The effect of the application of a large number of small loading cycles on the small strain stiffness of granular soils has been explored in the generalized multiaxial stress space using the Hollow Cylinder Torsional Apparatus (HCTA). The experimental investigation has been carried out on an angular to sub-angular silica sand. The sequence of cyclic loading has been performed for a range of stress levels and orientation of the principal stress axes. Accurate measurements of the quasi-elastic properties of the material were obtained using six non-contact dis placement transducer (based on...
TC4 International Workshop on Metrology for Geotechnics 2016
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Alessandro Pagliaroli, Alessandra Avalle, Paolo Tommasi, Francesca Budillon, Giuseppe Lanzo
Two soft offshore clays, recovered from the Adriatic shelf and the Tyrrhenian shelf margin (Italy), were subjected to cyclic simple shear tests. The influence of the cyclic shear strain amplitude as well as of vertical stress, void ratio and stress history on stiffness and damping properties of the soils, in a wide strain range (i.e. from 10-4 % to more than 1%), is examined and discussed. The role of soil structure on the cyclic behavior is also explored.
TC4 International Workshop on Metrology for Geotechnics 2016
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· 2016
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Grzegorz Andrzej Bialowas, Andrea Diambra, David Nash
The mechanical behaviour of reconstituted chalk deposited has been investigated in a comprehensive experimental campaign using measurement and dynamic testing in the form of bender elements. Characterisation of the small strain shear stiffness (G0) of this material has been performed over a range of the isotropic stress levels and over-consolidation ratios. A variation of (G0) with current stress and overconsolidation ratio is, for the first time, proposed for this material. Following the widespread idea that the process of remoulding chalk may release calcium carbonate, which provides a...
TC4 International Workshop on Metrology for Geotechnics 2016
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Salvatore Erminio, Andò Edward, Viggiani Gioacchino, Modoni Giuseppe
In the usual execution of triaxial tests, the longitudinal and volumetric strains are computed cumulatively from displacements measured outside the sample, and thus interpretation is based on the implicit assumption that samples deform homogeneously. This evident misconception often leads to inconsistent sometimes surprising results, mostly near failure where intensive strain localization usually takes place. Aiming to observe the distribution of strains, a series of triaxial compression and extension tests have been carried out at the Laboratoire 3SR of Grenoble. The tests have been...
TC4 International Workshop on Metrology for Geotechnics 2016
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· 2016
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