Diego Manzanal

Application of a New Rheological Model to Rock Avalanches: An SPH Approach

AbstractRock avalanches move large volumes of material causing a highly destructive power over large areas. In these events, it is possible to monitor the evolution of slopes but failure cannot be always prevented. For this reason, modelling of the propagation phase provides engineers with fundamental information regarding speed, track, runout and depth. From these data, it is possible to perform a better risk assessment and propose mitigation measures to reduce the potential hazard of specific area. The purpose of this paper is to present a depth integrated, SPH model, which can be used to simulate real rock avalanches and to assess the influence of the rheology on the avalanche properties. The paper compares the performance of different rheological models to reproduce the track, runout and depth of the final deposit for both, scale test and real events such as Frank and Thurwiesier rock avalanches. These sets of benchmarks provide information on the proposed model accuracy and limitations.

Application of a generalized plasticity constitutive model to a saturated pyroclastic soil of Southern Italy

The paper explores the capability of the advanced Pastor-Zienkiewicz constitutive model to accurate simulate the deformability, the shear strength and the static liquefaction of an air-fall volcanic (pyroclastic) soil, which was involved in catastrophic landslides of the flow type. The calibration and validation of two distinct versions of the PZ constitutive model is done for both undisturbed (loose) and remoulded (dense) saturated specimens. Either drained or undrained triaxial tests are properly reproduced through the model. The potentialities deriving from the use of an advanced constitutive model are pointed out.

Modelling of Fluidised Geomaterials: The Case of the Aberfan and the Gypsum Tailings Impoundment Flowslides

The choice of a pure cohesive or a pure frictional viscoplastic model to represent the rheological behaviour of a flowslide is of paramount importance in order to obtain accurate results for real cases. The principal goal of the present work is to clarify the influence of the type of viscous model—pure cohesive versus pure frictional—with the numerical reproduction of two different real flowslides that occurred in 1966: the Aberfan flowslide and the Gypsum tailings impoundment flowslide. In the present work, a depth-integrated model based on the v-pw Biot–Zienkiewicz formulation, enhanced with a diffusion-like equation to account for the pore pressure evolution within the soil mass, is applied to both 1966 cases. For the Aberfan flowslide, a frictional viscous model based on Perzyna viscoplasticity is considered, while a pure cohesive viscous model (Bingham model) is considered for the case of the Gypsum flowslide. The numerical approach followed is the SPH method, which has been enriched by adding a 1D finite difference grid to each SPH node in order to improve the description of the pore water evolution in the propagating mixture. The results obtained by the performed simulations are in agreement with the documentation obtained through the UK National Archive (Aberfan flowslide) and the International Commission of large Dams (Gypsum flowslide).

Fast Landslide Propagation: Alternative Modelling Techniques

We model debris flows using two sets of nodes, describing the water and the solid phases, which can move relative to each other. We present first the mathematical model which will be used, deriving it from Zienkiewicz-Shiomi model, and arriving to the depth integrated model proposed by Pitman and Le. Then, we present the rheological models describing solid, fluid and their interaction. Next, the SPH model for two phases will be described. Finally, we present some application cases where we will compare the results provided by the proposed model against those obtained using more simplified models.