1,721,202 research outputs found
Analisi e scelta di interventi di stabilizzazione e difesa di pendii in rocce fratturate interessati da fenomeni di scivolamento superficiale e crollo
No full textPhysical and Numerical models to rehabilitate a waste disposal site
No full textThe paper reports experimental and numerical studies carried out to investigate on the mechanical and hydraulic behavior of a large waste disposal of an abandoned asbestos mine. The waste disposal shows signs of incipient instability, involving large volumes of material. Studies to determine the parameters to design remedial measures were carried out in order to prevent significant instability and minimize environmental impacts
Modelli previsionali di meccanismi evolutivi di frane da colamento
No full textAnalisi dei risultati di modellazioni numeriche di frane da colamento effettuate con il metodo degli automi cellulari con l'utlizzo della legge di fluido dilatante di Bagnol
FLOWSLIDES IN FINITE SLOPES
No full textFlows of of loose saturated granular material can be the post failure evolution of slope sliding. This mechanism refers to the phenomenon of static liquefaction of loose material and is based on the hypothesis that the large deformations experienced during sliding phase induce excess pore pressure in material showing contractive behaviour. The paper reports a study aimed to the prediction of transformation from sliding to flow in a finite slope constituted by loose saturated sand. The study is based on the results of an extensive laboratory investigation on the potential of liquefaction of Toyoura sand, set up by Ishihara et al. (2000). They showed that, for a given minor principal stress, the major effective principal stress at the time of anisotropic consolidation is a parameter controlling dilative or contractive behaviour of the sand under otherwise identical conditions. The initial state of stress of sand slopes, at different void ratio and groundwater level conditions, is predicted by a finite difference model (FLAC) assuming fully drained conditions and linear elastic plastic behaviour of the material. On the basis of the numerical modelling results it is possible to completely define, in any point of the slope, the stress conditions by the two principal stresses and their direction. By relating this state of stress to the residual strength of the sand at the quasi steady state, it possible to localise the zones in the slope showing contractive behaviour and possibly subjected to flow sliding
Modellazione dei debris flow
No full textLa nota descrive un codice numerico tridimensionale messo a punto per prevedere l'evoluzione di debris flow in regime granulo-inerziale. Vengono quindi riportate due applicazioni del metodo: la prima consistente nella simulazione di una serie di modellazioni fisiche di debris flow effttuate in laboratorio; la seconda relativa ad una back analysdis ed a una analisi previsionale di un caso real
Modellazione teorica e sperimentale delle colate di detrito,
No full textLa nota riporta un lavoro a carattere sperimentale per analizzare le principali fasi delle colate di detrito. Un modello fisico costituito da un canale opportunamente alimentatp e strumentato con apparecchiature televisive e fotografiche è stato utlizzato per analizzare il colamento di materiale in seguito alla rottura di un versante. I risultati ottenuti dalla modellazione fisica e il confronto con lavori sperimentali riportati in letteratura mostrano come a differenti tipi di innesco corrispondano differenti caratteristiche di colata e che per il caso trattato sia necessario studiare il contributo delle pressioni neutra a partire dalla fase di rottura del versant
SLOPE GEOMETRY AS A TRIGGERING FACTOR OF FLOWSLIDES
No full textThe paper reports a study aimed to the prediction of flowsliding in finite slopes constituted by loose sand. Several authors showed the influence of the in situ state of stress on flowslide occurrence. The dependence of the potential for liquefaction from the pre-failure state of stress requires the determination of the state of stress in the slope. In this study the slope geometry has been investigated as a factor influencing the initial state of stress and hence flowslide occurrence. The initial state of stress of sand slopes characterised by different geometry and different void ratio and groundwater level conditions, is predicted by a finite difference model (FLAC) assum-ing fully drained conditions and linear elastic plastic behaviour of the material. On the basis of the numerical modelling results it is possible to completely define, in any point of the slope, the stress conditions and to analyses the effect of slope height and inclination. By relating this state of stress to the residual strength of the sand at the quasi steady state, it is possible to localise the zones of the slope potentially subjected to flow sliding
ANALYSIS OF DEBRIS FLOWS TRIGGERED BY RAINFALLS IN NORTHERN ITALY
No full textDebris flows are commonly triggered by an unusual presence of water. The sources of excess water can be: intense rainfall, rapid snowmelt and more rarely glacier or lake overflows which mobilise unconsolidated material in their path.
Mechanisms of occurrence of debris flows can be summarised as follows:
• static liquefaction of a landslide;
• collapse of a natural dam;
• increase in surface water flow on the gully bed
Three types of debris flow occurred in Northern Italy are discussed. A set of flume experiments is in progress with the purpose to simulate the different mechanisms of occurrence of these debris flow
Indagini e studi per il progetto di consolidamento di un versante su cui insiste una discarica di RSU
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