 |
| Titel |
Modelling dual-permeability hydrological system and slope stability of the Rocca Pitigliana landslide using COMSOL Multiphysics |
| VerfasserIn |
Wei Shao, Thom Bogaard, Mark Bakker, Matteo Berti |
| Konferenz |
EGU General Assembly 2014
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250089518
|
| Publikation (Nr.) |
 EGU/EGU2014-3723.pdf |
|
|
|
|
|
| Zusammenfassung |
| The accuracy of using hydrological-slope stability models for rainfall-induced landslide
forecasting relies on the identification of realistic landslide triggering mechanisms and the
correct mathematical description of these mechanisms. The subsurface hydrological
processes in a highly heterogeneous slope are controlled by complex geological conditions.
Preferential flow through macropores, fractures and other local high-permeability zones can
change the infiltration pattern, resulting in more rapid and deeper water movement.
Preferential flow has significant impact on pore water pressure distribution and consequently
on slope stability. Increasingly sophisticated theories and models have been developed to
simulate preferential flow in various environmental systems. It is necessary to integrate
methods of slope stability analysis with preferential flow models, such as dual-permeability
models, to investigate the hydrological and soil mechanical response to precipitation in
landslide areas.
In this study, a systematic modeling approach is developed by using COMSOL
Multiphysics to couple a single-permeability model and a dual-permeability model with a soil
mechanical model for slope stability analysis. The dual-permeability model is composed of
two Richards equations to describe coupled matrix and preferential flow, which can be used
to quantify the influence of preferential flow on distribution and timing of pressure
head in a slope. The hydrological models are coupled with a plane-strain elastic
soil mechanics model and a local factor of safety method. The factor of safety is
evaluated by applying the Mohr-Coulomb failure criterion on the effective stress
field.
The method is applied to the Rocca Pitigliana landslide located roughly 50 km south of
Bologna. The landslide material consists of weathered clay with a thickness of 2-4m
overlying clay-shale bedrock. Three years of field data of pore pressure measurements
provide a reliable description of the dynamic hydrological response to transient rainfall
intensity. So far, the landslide has been successfully modelled using a diffusion wave
approach. In this study, the main focus will be on evaluating the predictive power of
different model approaches by inter-comparison of new and existing simulation
results. This will make it possible to quantify the influence of preferential flow on
subsurface hydrological processes and slope stability in the Rocca Pitigliana landslide. |
|
|
|
|
|
|