1,721,042 research outputs found
Modeling of complex deep-seated mass movements in the central-southern Marches (Central Italy).
No full textA new approach for defining Slope Mass Rating in heterogeneous sedimentary rocks using a combined remote sensing GIS approach
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Geomorphological features and 3D modelling of Montelparo mass movement (Central Italy).
No full textThe ancient village of Montelparo (Marche region, Central Italy) is affected by a large translational mass movement. The relief is modeled on
arenaceous and arenaceous-pelitic units overlying pelitic-arenaceous terrains; the bedding strata form a gently dipping monocline. The
translational slide is about 1100 m long and 500–700 m wide. The upper boundary between the stable area and the sliding mass is marked by a
large active trench near the hilltop. The main sliding surface is located at a depth ranging between 65 and 100 m, in the politic-arenaceous unit. We
studied the mechanism of the slope instability along the stratigraphic contact between a rigid arenaceous unit and an underlying ductile pelitic unit.
The uncovering of the contact caused by the intense downcutting processes of the river at the hill foot during the Holocene, favoured the onset of
the movement. This was enhanced by the fractured bedrock and especially by the jointing. We created a numerical model based on the finite
differences code FLAC_3D by using a specific approach for mesh generation. The model suggests a further enlargement and deepening of the
trench, and a sliding direction not aligned with the slope dip direction. Failure in the model concentrates at and around the main trench, all the
other elements staying in an elastic state and inducing a rigid sliding. The model shows that both the failure onset and the current evolutionary
state can be explained by the geological and static conditions of the slope
la frana mista di Penna S. Andrea (Teramo, Abruzzo): metodologia di controllo per la mitigazione del rischio idrogeologico
No full textSurface Water Flow Balance of a River Basin Using a Shallow Water Approach and GPU Parallel Computing—Pescara River (Italy) as Test Case
Full text linkThe analysis and prevention of hydrogeological risks plays a very important role and, currently, much attention is paid to advanced numerical models that correspond more to physical reality and whose aim is to reproduce complex environmental phenomena even for long times and on large spatial scales. Within this context, the feasibility of performing an effective balance of surface water flow relating to several months was explored, based on accurate hydraulic and mathematical-numerical models applied to a system at the scale of a hydrographic basin. To pursue this target, a 2D Riemann–Godunov shallow-water approach, solved in parallel on a graphical processing unit (GPU), able to drastically reduce calculation time, and implemented into the RiverFlow2D code (2017 version), was selected. Infiltration and evapotranspiration were included but in a simplified way, in order to face the calibration and validation simulations and because, despite the parallel approach, it is very demanding even for the computer time requirement. As a test case the Pescara river basin, located in Abruzzo, Central Italy, covering an area of 813 km2 and well representative of a typical medium-sized basin, was selected. The topography was described by a 10 × 10 m digital terrain model (DTM), covered by about 1,700,000 triangular elements, equipped with 11 rain gauges, distributed over the entire area, with some hydrometers and some fluviometric stations. Calibration, and validation were performed considering the flow data measured at a station located in close proximity to the mouth of the river. The comparison between the numerical and measured data, and also from a statistical point of view, was quite satisfactory. A further important outcome was the capability to highlight any differences between the numerical flow-rate balance carried out on the basis of the contributions of all known sources and the values actually measured. This characteristic of the applied modeling allows better calibration and verification not only of the effectiveness of much more simplified approaches, but also the entire network of measurement stations and could suggest the need for a more in-depth exploration of the territory in question. It would also enable the eventual identification of further hidden supplies of water inventory from underground sources and, accordingly, to enlarge the hydrographic and hydrogeological border of the basin under study. Moreover, the parallel computing platform would also allow the development of effective early warning systems, for example, of floods
La frana mista di S.Andrea (Teramo,Abruzzo): metodologia di controllo per la mitigazione del rischio idrogeologico
No full textRock slope stability analysis on the complex Livorno coastal cliff (Tuscany, Italy)
No full textThe landscape of the south coast of Livorno city (Tuscany, Italy) is characterized by sandstone headlands and sandy pocket beaches affected by serious stability problems. Lithological features and physical-chemical processes involve many slope failures concerning the sandstone cliff and extending all over the cliff height; these failures often threaten people and facilities. The most prominent positive relief landform is structurally controlled by three main closely spaced joint sets. The presence of lean- ing and collapsed rock blocks suggests that erosion and mass wasting maintain the cliff steepness and elevate risk conditions. The sandstone mechanical properties and discontinuity pattern have been investigated in order to determine the response of the rock mass to subaerial and ma- rine stresses. The sandstone outcrops were characterized according to the Rock Mass Rating (Bieniawski, 1989) and the Slope Mass Rating (Ro- mana, 1985; 1993). Such data has been reported in a GIS system in order to determine the landslide susceptibility of the cliff. Some numerical modelling, with a code at Distinct Element Method model, were carried out to evaluate stresses and displacement distribution near the free sur- face of a steep slope face, as a function of steepness, dip direction and rock mass quality. Then some fall simulations were carried out, to make a back analysis of previous events and to obtain a more general outline of possible movements. The results showed that rock mechanics and com- puter modelling can be effective tools in predicting the rock-mass stabili- ty, determining the mechanism by which blocks fall from steep slopes and their possible trajectories
Tecniche di risanamento di aree calanchive ad alto rischio idrogeologico: l’esempio della media Valle dell’Alento (Abruzzo)
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