Category: Prove triassiali

Prove triassiali

UR n.4 (Università degli Studi di Genova)

Post a comment. Determination of Pile Base Resistance in Sands. Advances in piling technology permit the installation of several types of piles, particularly nondisplacement piles, at lower costs than was possible in the past. Additionally, there is a growing realization in the foundation engineering industry that certain types of deep foundations such as large-diameter drilled shafts are conservatively designed Hirany and Kulhawy ; Harrop-Williams ; De Mello and Aoki Based on the method of installation, pile foundations are classified as either displacement or nondisplacement piles.

The load-carrying capacity of both displacement and nondisplacement piles consists of two components: Base resistance and side resistance. In the present study, the base load-settlement curves of axially loaded piles bearing in sand are obtained for different stresses and densities using the finite-element analysis with a nonlinear elastic-plastic constitutive model.

Fioravante, V. Vilar Franke, E. Bolton, M. Chen, W. Soil plasticity: Theory and implementation.

Elsevier Science, New York. Bellotti, R. Borja, R. Desai, C. Constitutive laws for engineering materials with emphasis on geologic materials. Prentice-Hall, Englewood Cliffs, N.

Duncan, J. Ghionna, V. Numerical methods in geotechnical engineering. McGraw-Hill, New York. Lee, C. Kondner, R.Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. If you continue browsing the site, you agree to the use of cookies on this website. See our User Agreement and Privacy Policy. See our Privacy Policy and User Agreement for details. If you wish to opt out, please close your SlideShare account.

prove triassiali

Learn more. Published on Jan 28, SlideShare Explore Search You. Submit Search. Home Explore. Successfully reported this slideshow. We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime. Upcoming SlideShare. Like this presentation? Why not share! Marine — Structural, Geotechnical A Embed Size px.

Start on. Show related SlideShares at end. WordPress Shortcode.The Stromboli island is one of the most active volcanoes in the world.

Its structural evolution has been characterized by four large sector collapses affecting the NW flank, resulting in the creation of the Sciara del Fuoco horseshoe-shaped depression. In this study the local and general stability of the Sciara del Fuoco recent volcanic debris has been analysed. These loose deposits represent a potential unstable mass that can be mobilized evolving in granular flow running along the Sciara del Fuoco into the sea, eventually forming tsunami waves as in the latest landslide events of December and January The paper presents the first achievements toward the stability analysis of volcanic debris via numerical modeling according to the following steps: 1 geotechnical characterization of materials 2 calibration of the numerical model based on experimental geotechnical data.

A set of biaxial tests has been simulated by numerical modelling and compared with the experimental triaxial compression tests. The sensitivity analysis has been focused on finding the particle mechanical parameters that better represent the rheology of the volcanic debris at the macroscopic scale. Specific mathematical relations between mechanical parameters of single particles and particles assembly have been found as a function of the acting stress state. These relations represent the first goal in determining the actual rheology of granular materials and in evaluating its influence on slope dynamics by performing particle based numerical modelling.

Location of Repository. Apuani, M.

UR n.4 (Università degli Studi di Genova)

Masetti, A. Uttini, L. Vezzoli and C. OAI identifier: oai:air. Suggested articles.Supporto tecnico: Umberto Bruschini, Giuseppe Riotto. I rusultati delle prove di laboratorio condotte, sulle singole radici e su provini radicati naturalmente, permettono inoltre la calibarzione di un semplice modello di comportamento appositamente proposto. Nel corso degli ultimi decenni sono state sviluppate diverse procedure per effettuare analisi di previsione spaziale dei fenomeni franosi, a diverse scale e basati su diversi approcci.

Le categorie di fattori, che come osservato in letteratura Tab. Tabella 1.

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Parametri quasi sempre considerati in letteratura sono quelli di tipo geomorfologico. Tali fattori sono anche quelli normalmente presi in considerazione nelle zonazioni effettuate a scopo di pianificazione territoriale, che spesso si dimostrano non del tutto accurate e rappresentative. Sito webGIS demo. Blanco-Canqui et al.

Prove di questo tipo furono condotte anche da Maher and Gray e da Michalowski and Cermak in cella triassiale ad elevate tensioni di confinamento su campioni di sabbia medio-fine rinforzata, da fibre sintetiche e naturali oppure fili di metallo. Regione Lazio e Regione Piemonte. Le regole puramente empiriche, che spesso vengono impiegate per il dimensionamento di tali opere, sono state analizzate in riferimento alla normativa vigente Norme Tecniche per le Costruzioni integrate con la Circolare Applicativa — D.

Per quantificare la resistenza del terreno con e senza le radici sono state eseguite prove di taglio diretto e prove triassiali. I mold utilizzati per le prove triassiali appaiono come in figura 2. Vengono trascurati qui i dettagli relativi alla preparazione dei campioni, che saranno resi disponibili in Bovolenta et al.

Le analisi condotte hanno dimostrato che una copertura vegetale, se correttamente scelta e messa a dimora, consente un efficace consolidamento degli strati superficiali di terreno apportando un notevole beneficio in coltri superficiali sature.

Search for: Close. Linee Guida per la redazione di Carte degli interventi per la mitigazione del rischio da frana. Procedura automatica in GIS per la redazione di Carte degli interventi per la mitigazione del rischio da frana. Compito 1. Risultati A. Fattori affidabili. Importanza della discretizzazione. Gli interventi sono stati raggruppati nelle seguenti sei famiglie: Riprofilatura. Opere di sostegno.

Rinforzo con inclusioni. Interventi protettivi di ingegneria naturalistica.I documenti in POLITesi sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione. I risultati raccolti mostrano che il comportamento di ritenzione del terreno conferma alcune caratteristiche del comportamento di ritenzione di terreni argillosi deformabili, anche se, in un range di basse suzioni, si discosta dal precedente modello di comportamento, probabilmente a causa delle frazioni di limo e di sabbia dominanti.

La rigidezza e lo smorzamento confermano gli andamenti previsti al variare della frequenza, in particolare la rigidezza diminuisce, mentre lo smorzamento aumenta con contenuto di acqua.

La risposta ciclica asintotica in condizioni stazionarie viene raggiunta in un numero relativamente basso di cicli per i campioni non saturi.

Abstract in inglese The dissertation presents the results of an experimental investigation on the hydraulic and the dynamic behaviour of a compacted silty soil. Starting from some considerations about the Normativa Tecnicathe Italian unified design Code, in particular related to the hydraulic and the seismic analysis of earth embankments, an experimental investigation was designed to characterise the main hydraulic and dynamic properties of a soil used for the construction of an embankment in Viadana.

The soil was prepared in the laboratory by dynamic compaction, trying to reproduce as much as possible the field conditions. Afterwards, different techniques were adopted to draw the water retention domain of the compacted soil, and cyclic triaxial tests were run to analyse stiffness and damping as a function of water content in a range of frequency between 0.

The results collected show that the retention behaviour of the soil confirms a few features of the retention behaviour of deformable clayey soils, although, in the low suction range, it deviates from previous established behaviour pattern, probability due to the dominating silt and sand fractions.

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Stiffness and damping confirm expected trends with varying frequency, with stiffness decreasing and damping increasing with water content. Steady state asymptotic cyclic response is reached in a relatively low number of cycles for the unsaturated samples. Anno accademico. Titolo della tesi. Experimental investigation on the hydraulic and cyclic behavior of Viadana silt. Abstract in italiano. Il seguente lavoro presenta i risultati di un'indagine sperimentale riguardanti il comportamento idraulico e dinamico di un terreno limoso compattato.

Abstract in inglese.

prove triassiali

The dissertation presents the results of an experimental investigation on the hydraulic and the dynamic behaviour of a compacted silty soil.

Tipo di documento. Tesi di laurea Magistrale. Tesi completaPDF.Cerca nel sito. Mappa del sito. Journal Paper.

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Some remarks on bimodality effects of the hydraulic properties on shear strength of unsaturated soils. Hydro-mechanical response of collapsible soils under different infiltration events. Artificial ground freezing of a volcanic ash: laboratory tests and modelling. Breakage of an artificial granular material under loading. Hydromechanical behaviour of a silty sand from a steep slope triggered by artificial rainfall: from unsaturated to saturated conditions. Consequences on water retention properties of double-porosity features in a compacted silt.

Deformation induced by wetting: a simple model. Rainfall induced instabilities: a field experiment on a silty sand slope in northern Switzerland. NUTH, J. M A laboratory investigation on an undisturbed silty sand from a slope prone to landsliding.

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Discussion on "Estimating hydraulic conductivity from piezocone soundings". CHAI, P. HINO, Y. Ge'otechnique 61, No. Corrigendum to Deformation induced by wetting: a simple model.

Freezing-thawing tests on natural pyroclastic samples. In: Poromechanics V. Stress-path effects on the grading of an artificial material with crushable grains.

Unsaturated hydraulic conductivity of a silty sand with the instantaneous profile method. Unsaturated Soils: Research and Applications. Napoli, giugnovol. Experimental investigation of the evolution of grading of an artificial material with crushable grains under different loading conditions.I documenti in POLITesi sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione. Lo studio si concentra su terreni in condizioni non drenate che hanno un comportamento, in prima approssimazione, indipendente dal tempo.

Si sono eseguite analisi statiche in assialsimmetria, utilizzando un legame costitutivo elastico-perfettamente plastico con legge di rottura alla Tresca, per ottenere la relazione fra sforzi e spostamenti del fronte curva caratteristica e lo sviluppo di plasticizzazioni intorno al fronte.

Nel passato si sono utilizzate le prove di estrusione triassiali per prevedere qualitativamente la risposta di tunnel, tuttavia queste prove sono affette dai problemi legati alla sperimentazione in scala.

prove triassiali

In particolare si nota che per effetto dello scavo visto come progressiva riduzione della pressione al fronte nelle prove di estrusione sulla base del campione opposta alla camera di estrusione si assiste ad una progressiva diminuzione dello stato di sforzo, mentre nel caso di scavi di gallerie lo sforzo corrispondente rimane costante.

Abstract in inglese Tunnelling has become a preferred construction as urbanization increases and available land decreases in all over the world. One method that is commonly used in tunneling is so called conventional tunnel method CTM ; despite tunnel boring machines are becoming more popular.

One of the main consideration concerning construction of tunnel is the stability of tunnel face during excavation.

Scientist and engineer depend on physical modelling to understand different phenomena such as deformation patterns and failure mechanism. Since full-scale physical model is expensive and hard to repeat, it is preferable to use reduced model.

There are three categories of reduced physical model: centrifuge, 1-g scale and extrusion tests.

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The main aim of the present research is to study stability of the deep underground opening of CTM by adapting results of extrusion tests which are obtained numerically thanks to the use of the commercial code Midas GTS NX The study focuses on rocks or soils whose viscous effect are negligible and behave under undrained condition. Static analyses using an elasto-plastic Tresca constitutive model with axisymmetric model are used to obtain relationship between stresses and displacements or characteristic curve and the development of platic zone surrounding the face.

Interpretation of the results is done by considering real behaviour of phenomena which are three-dimensional problems. Therefore, the results have been always compared with those of a 3D tunnel as a reference model. Although the past experiments on extrusion furnished a guide that is sufficiently reliable for qualitative predictions of the phenomena, however, problems that are typical of studies performed in the laboratory do exists.

One of the problems associates with an effect of small scale due to geometry. This leads us to investigate any possible effect on boundaries in extrusion tests considering different specimen dimensions.

The study indicates that the numerical results of extrusion tests show a strong dependency of the geometry of specimen and the ratio between initial stress and shear strength.


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