Nessun titolo diapositiva

1
University of Bologna Workplan
2
Staff

• Prof. Alberto Lamberti, Scientific Responsible
• Dr. Renata Archetti
• Dr. Matteo Berti
• Prof. Paolo Ghilardi
• Dr. Sandro Longo
• Dr. Alessandro Simoni
• Dr. Barbara Zanuttigh

3
WP1 Monitoring and Data base

• Task 1.1 - Feasibility design and laboratory
  calibration
• of the discharge measuring device
• choice of the transducer(s)
• scale model and calibration of the device
• Task 1.2 - Field activity in
  Cortina dAmpezzo area
• 
  Objectives
• characterisation of the geometry of the natural
  channel section
• quantification of the stone size degradation
  processes by abrasion and splitting
• 
  Methodology
• Collection of data (section width, depth, shape
  and grain size distribution)
• in the initiation area
• in the equilibrium reach
• in the deposition area

4
Croda Rossa
5
Initiation Area Mobilisation area
6
Channel morphometry
15-20 debris flow channels, 10 cross sections
field survey in case of events - 10 flow
sections corresponding to the previously surveyed
cross sections - volume estimates field derived
parameters - maximum velocity and discharge -
estimate of Bingham parameters - estimate of
bulking along the channel
7
Debris characteristics
initiation area
sampling
deposition area
lab testing - grain-size distribution -
particle shape analysis - shear resistance
characteristics - critical state line (scaling
analysis) - limit states of compactness (relative
density)
8
WP2 Updating of existing models

• 
  Objective
• to update existing 1D models aiming to represent
  degradation and entrainment/deposition
• 
  Methodology
• analysis of erosion and deposition equations
• implementation of a finite difference scheme
  (Roe)
• degradation by abrasion and splitting based on
  energy dissipation (Reye, 1849 Krogh, 1980,
  1999)

9
Mathematical model
1 momentum equation for the whole mixture

• 2 continuity equations
• Mixture
• Solid phase

1 equation for bed evolution (not present in the
steady bed model)

• closure equations
• erosion/deposition rate (not present
  in the steady bed model)
• friction

10
1D model, two phases, movable bed
11
1D model, two phases, steady bed
12
Movable bed model
- deposition of grains
- water continues to flow
Steady bed model
- grains and water stop together
13
WP2 Updating of existing models

• 
  Objective
• to represent the natural formation of levees
  (regime width and section in the alluvial
  fan)
• 
  Methodology
• synthesis of the debris channel data base into
  regime equations providing maximum width of
  hill-slope debris flows

14
Landro
15
WP2 Updating of existing models

• 
  Objective
• to quantify and represent degradation of
  materials along the flow
• 
  Methodology
• laboratory tests on abrasion and crushing of
  natural stones from debris areas, standard
  abrasion tests and drop/falling-hammer tests
• analysis of the observed degradation along debris
  channels

16
WP2 Updating of existing models

• Objective
• to evaluate maximum flow depth when roll waves do
  develop (or debris jams are formed?)
• 
  Methodology
• laboratory experiments in a rotating drum
  (granular flow) and in an inclined chute
  (granular and muddy flows) aiming to represent
  wave formation, kinematics and evolution
• theoretical prediction of final wave height and
  comparison with laboratory experiments and
  field monitoring

17
Laboratory experiments
Chute
Rotating drum
18
Rotating drum, 2 rpm, sand grains 0.3-0.4 mm
19
Rotating drum, 5 rpm, sand grains 0.3-0.4 mm
20
WP2 Updating of existing models

• 
  Objective
• to analyse segregation mechanism and effects on
  deposition and debris jamming
• 
  Methodology
• laboratory experiments in an inclined chute
  pointing out vertical segregation and the
  related differential convection
• micro-mechanical modelling of segregation based
  on impacts representation

21
WP3 Evaluation and comparison of existing models

• Identification of relevant parameters for
  synthetic global models, independent variables
  (magnitudo, basin characterisation, debris
  characterisation, alluvial fan slope...),
  dependent variables (extension of deposit,
  velocity of debris, stream depth...)
• Selection of empirical formulae, validation and
  calibration and error statistics

22

WP5 GIS modelling, hazard assessment and zoning

• Co-operation in preparing risk maps of selected
  areas
• evaluation of torrent hazards based on
  mechanicistic models, representing both real
  and synthetic events with different return
  periods
• comparison of results with field data

23

WP6 Technical countermeasures and warning systems

• Participation in designing Fiames warning system
• reviewing of other deliverables of the WP

24
Fiames
25
WP7 Guidelines for end-users

• Participation in preparing some documents
• reviewing of other documents