Search results for "Slope stability"
showing 8 items of 18 documents
Analyzing the role of soil water retention curve in slope stability for differently structured soils
2016
We analyzed the mechanical and hydrological effects of soil water retention curve (SWRC) models on the slope stability analyses of soils with unimodal and bimodal behavior. We used three different SWRC models, two bimodal models (Ross&Smettem and Dexter) vs. the traditional van Genuchten model, to evaluate the Factor of Safety (FS) of a simple designed hillslope, based on the Bishop approach for unsaturated soils. Two formulations for term were also considered. Results indicate that in cases of clayey soils, changes in FS obtained with different SWRC models especially at soil moisture values within the residual zone. In sandy soils the choice of formulations can be more important…
The stabilization of a slope-viaduct system without closing traffic
2015
ABSTRACT A case history concerned with the stabilisation of a slope-viaduct system is reported. The two-carriageway viaduct was built 39 years ago on a rather gentle slope that did not show any sign of instability. In 2010 a landslide took place and damaged the viaduct. As the relocation of the motorway was deemed unpracticable, the alternative solution of stabilising the slope and repairing the viaduct was chosen. The owner asked to design remedial measures that did not require the closure of the viaduct. This was possible since the movements of the slided mass were slow and regular. The slope-viaduct system was stabilised by improving, firstly, the bearing conditions of the decks, then st…
Physically based modeling of rainfall-triggered landslides: a case study in the Luquillo forest, Puerto Rico
2013
This paper presents the development of a rainfall-triggered landslide module within an existing physically based spatially distributed ecohydrologic model. The model, tRIBS-VEGGIE (Triangulated Irregular Networks-based Real-time Integrated Basin Simulator and Vegetation Generator for Interactive Evolution), is capable of a sophisticated description of many hydrological processes; in particular, the soil moisture dynamics are resolved at a temporal and spatial resolution required to examine the triggering mechanisms of rainfall-induced landslides. The validity of the tRIBS-VEGGIE model to a tropical environment is shown with an evaluation of its performance against direct observations made w…
Gis-analysis to assess landslide susceptibility in a fluvial basin of NW Sicily (Italy).
2008
Abstract Landslide hazard assessment, effected by means of geostatistical methods, is based on the analysis of the relationships between landslides and the spatial distributions of some instability factors. Frequently such analyses are based on landslide inventories in which each record represents the entire unstable area and is managed as a single instability landform. In this research, landslide susceptibility is evaluated through the study of a variety of instability landforms: landslides, scarps and areas uphill from crown . The instability factors selected were: bedrock lithology, steepness, topographic wetness index and stream power index. The instability landform densities computed f…
The use of soil water retention curve models in analyzing slope stability in differently structured soils
2017
Abstract This study analyzes whether and at what rate the parameterization of the Soil Water Retention Curve (SWRC) affects the analysis of shallow slope stability for differently structured unsaturated soils. Advanced empirical or physically-based equations of SWRCs have been proposed in literature to describe soil systems characterized by the so-called bimodal porous domain. In unsaturated soils, SWRC affects the stability assessment in two ways. It influences the resistance properties in terms of shear strengths, which depend on the soil water suction; and it affects the hydrological process modeling (e.g. infiltration) directly influencing soil moisture patterns and indirectly influenci…
Early warning thresholds for partially saturated slopes in volcanic ashes
2013
Rainfall-induced landslides in steep soil slopes of volcanic origin are a major threat to human lives and infrastructure. In the context of constructing early warning systems in regions where extensive data on landslide occurrences and associated rainfall are inexistent, physically-based tools offer the possibility to establish thresholds for measurable field quantities. In this paper, a combined finite element infinite slope model is presented to study the transient hydraulic response of volcanic ash slopes to a series of rainfall events and to estimate seasonal safety factors. Furthermore, analytical considerations of partially saturated infinite slopes are made to define capillary stress…
Effects of the foot evolution on the behaviour of slow-moving landslides
2011
The paper presents a time-dependent 2D numerical model which has been developed with the purpose of highlighting the effects of the slope foot evolution on the behaviour of slow-moving landslides. The model allows to quantitatively analyse how foot mass variations can influence the stability and the movement rates of the landslide. The landslide body is modelled as composed of two rigid blocks sliding on two different planes and interacting through a common boundary, which position is assumed fixed during the analysis. A finite difference approach is used to discretize the time. For each time increment, changes in model parameters are allowed, including variations in shearing resistances, g…
The preservation of the Agrigento Cathedral
2013
The Agrigento Cathedral was built about nine centuries ago on the edge of a steep slope made up of alternating inclined layers of soft calcarenites and fine-grained soils; its behaviour has never been satisfactory especially as far as the North aisle is concerned. Many corrective measures have been attempted during its lifespan and also a few years ago. They proved invariably unsuccessful. Recent geotechnical investigations, referred to in the paper, permitted to find out that the main cause of the Cathedral distress is a sliding mechanism involving the upper zone of the slope underlying the North aisle; consequently the essential requirement for the preservation of the Cathedral is the sta…