Application of a SPH depth-integrated model to landslide run-out analysis

Hazard and risk assessment of landslides with potentially long run-out is becoming more and more important. Numerical tools exploiting different constitutive models, initial data and numerical solution techniques are important for making the expert’s assessment more objective, even though they cannot substitute for the expert’s understanding of the site-specific conditions and the involved processes. This paper presents a depth-integrated model accounting for pore water pressure dissipation and applications both to real events and problems for which analytical solutions exist. The main ingredients are: (i) The mathematical model, which includes pore pressure dissipation as an additional equation. This makes possible to model flowslide problems with a high mobility at the beginning, the landslide mass coming to rest once pore water pressures dissipate. (ii) The rheological models describing basal friction: Bingham, frictional, Voellmy and cohesive-frictional viscous models. (iii) We have implemented simple erosion laws, providing a comparison between the approaches of Egashira, Hungr and Blanc. (iv) We propose a Lagrangian SPH model to discretize the equations, including pore water pressure information associated to the moving SPH node

Treatment planning of intracranial lesions with {VHEE}: comparing conventional and {FLASH} irradiation potential with state-of-the-art photon and proton radiotherapy

The treatment of deep-seated tumours with electrons of very high energies (VHEE, 70-150 MeV) has already been explored in the past, suggesting that a dosimetric coverage comparable with state-of-the-art proton (PT) or photon radiotherapy (RT) could be achieved with a large ( > 10) number of fields and high electron energy. The technical and economical challenges posed by the deployment of such beams in treatment centres, together with the expected small therapeutic gain, prevented the development of such technique. This scenario could radically change in the light of recent developments that occurred in the compact, high-gradient, electron acceleration technology and, additionally, of the experimental evidence of the sparing of organs at risk achieved in ultra-high dose rate irradiation, also referred to as FLASH. Electrons with the energy required to treat intracranial lesions could be provided, at dose rates compatible with what is needed to trigger the FLASH effect, by accelerators that are a few metres long, and the organ sparing could be exploited to significantly simplify the irradiation geometry, decreasing the number of fields needed to treat a patient. In this paper, the case of two patients affected by a chordoma and a meningioma, respectively, treated with protons in Trento (IT) is presented. The proton plans have been compared with VHEE plans and X-ray intensity-modulated radiotherapy (IMRT) plans. The VHEE plans were first evaluated in terms of physical dose distribution and then assuming that the FLASH regimen can be achieved. VHEE beams demonstrated their potential in obtaining plans that have comparable tumour coverage and organs at risk sparing when benchmarked against current state-of-the-art IMRT and PT. These results were obtained with a number of explored fields that was in the range between 3 and 7, consistent with what is routinely performed in IMRT and PT conventional irradiations. The FLASH regimen, in all cases, showed its potential in reducing damage to the organs placed nearby the target volume, allowing, particularly in the chordoma case where the irradiation geometry is more challenging, a better tumour coverage with respect to the conventional treatments

Sulla doppia porosità di alcuni terreni piroclastici della Regione Campania

Incontro annuale dei Ricercatori in Ingegneria Geotecnica (IARG

Movimenti Franosi Veloci in Terreni Piroclastici: Considerazioni sulla Modellazione dei Meccanismi di Innesco

Incontro Annuale dei Ricercatori di Geotecnica 2005 - IARG 200

Flow-like mass movements in pyroclastic soils: remarks on the modelling of triggering mechanisms

A particularly dangerous hazard is represented by flow-like mass movements involving volcanic soils. Notwithstanding their similar consequences, such phenomena can be characterised by different first and post-failure mechanisms, in relation with regional, seasonal and local features, triggering factors and mechanisms, soil properties, boundary conditions and so on. The present paper analyses the first-failure stage of landslides triggered by rainfall, focusing the attention on Southern Italy, where a large area is covered by pyroclastic soils originated by different volcanic apparata. On the basis of the available data set, the landslides intensity, freque ncy and consequences proved to be strictly related to the geological setting, where the triggering mechanisms result quite different during the hydrological year. Hence, referring to the spring season and to a sample area where several triggering mechanisms have been recognised, the paper evidences the potentialities of a multidisciplinary approach towards an appropriate back-analysis of occurred phenomena, that represents a fundamental step for an adequate hazard assessment

Colate rapide in terreni piroclastici: analisi di un tipico meccanismo di innesco

Incontro Annuale dei Ricercatori di Geotecnica, IARG 2006, Pis

Detection of mechanisms for destructive landslides in Campania region – southern Italy.

The detection of the mechanisms that control the landslides of the flow-type is a fundamental issue in the risk analysis. This task is challenging when large areas are affected by landslides and related geotechnical datasets only refer to small portions of the analysed area. In such a case, a methodology based on a multi-scale approach can be profitably used. The present paper deals with the application of the above methodology to an area of the Campania region in southern Italy which is among the most at risk areas in Europe. Particularly, at small scale, preliminary insights on landslides mechanisms are obtained through the F-N curves. Then, referring to the medium scale, evaluations on the predisposing factors and triggering mechanisms are carried out through basic geological, geotechnical and hydrological analyses. Finally, the role played by the local geological and geotechnical features for the onset of different triggering mechanisms is assessed, at large scale, by using standard and advanced geotechnical analyses