River Loire levees hazard studies CARDigues model principles and utilization examples on Blois levees

Transcription

1 River Loire levees hazard studies CARDigues model principles and utilization examples on Blois levees Eduard Durand 1,a, Jean Maurin 2, Bastien Bridoux 2, Arnaud Boulay 3 and Arnaud Bontemps 1 1 CEREMA, Direction Territoriale Normandie-Centre, Laboratoire Régional de Blois, 11 rue Laplace, Blois Cedex, France 2 DREAL Centre-Val de Loire, 5 avenue Buffon, CS96407, Orléans cedex 2, France 3 DDT45, faubourg Bannier, Orléans, France Abstract. 1 Introduction & concept 1.1 Context of hazard studies 1.2 Figure 1. Description of the levee system discretization in representative levee segments (after [10]) a Corresponding author: Edouard.durand@cerema.fr b levee classes are function of levee height and protected population The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (

2 P(n) Qi P(na) x P(nr) (Prupture) Qi (Prupture) Qi [1- ((1- P(s)) x (1- P(ei)) (1- P(ee)) x (1- P(g)) x (1- P(sh))) MAX [P(s);P(ei)); x P(ee); P(g); P(sh)] P(n) an i50 P(n) Qi x P(Qi) Figure 2. Graphic showing the principle of probabilistic space discretization used in CARDigues (after [6].). For example, the shaded area is affected to the Q 500 flood event. 2 Entrance data of CARDigues 2.1 General data 2.2 Topographic data Figure 3. Characteristic points of a levee profile in CARDigues model (courtesy Durand E.) 2.3 Hydraulic data 2

3 2.4 Geotechnical data 2.5 Structural data and disorders 2.6 Reinforcement, protection or amelioration data 3.1. Overflowing Figure 4. Principle of erosion by overflowing process ([8], Courtesy Y. Deniaud) 3.2 Internal erosion 2.7 Management data 3 Breaching processes and failure mechanisms Figure 5. Examples of internal erosion processes and localizations in the levee or its foundation ([8], Courtesy Y. Deniaud) 3

4 3.3 slope instability Figure 6. Examples of rotational slope slidings (after [8], Courtesy Y. Deniaud) 3.4 External erosion 3.5 Uplift Figure 7. Principle of a slope sliding caused by uplift ([8], Courtesy Y. Deniaud) 3.6 Other breaching processes 4 Probability calculations 4.1 Hypothesis 4.2 Overflowing 4

5 Figure 10. Table of coefficients applied on Bligh raw ratio (after [6]) 4.4 Slope instability Figure 8. Example of overflow breach probability weighting coefficient function of levee width (after [6]) 4.3 Internal erosion Figure 11. Sliding appearance probability function of factor of safety ranges (after [6]) Figure 9. Internal erosion appearance probability function of Bligh ratio (after [6]) 5

6 F h ho hc Z bd h ' L L L L 3 Figure 12. Slope sliding breach probabilities based on internal erosion appearance probabilities over-ranking (after [6]) 4.5 External erosion k f L1 Z d k bu bu k f L3 Z d k bd bd 4.6 Uplift Figure 14. Uplift appearance probabilities function of ranges of factor of safety (after [6]) Figure 13. Cross-section and notations used for uplift security factor calculation (after [12]) 6

7 E3S Web of Conferences 7, (2016) FLOODrisk rd European Conference on Flood Risk Management 5 Example of results on Blois levee system 5.1 Presentation of Blois levee system ) ( 5 8 ' ( ( ( & 5 ( ) () &5 ( 4 & ;=! 0= ) ( ) & ( ) 4 &;=!& ( O ;# # 6222 (! ( D & Figure 16. Blois levee left bank levee profile (black line) and the nine flood level taken into account in CARDigues Blois model (after [3]) 5.4 Blois levee cross-section report 4 & ;3!& 4 ) ( ( # ( ( ) ( ( ( )!& L ( & Figure 15. Blois levee systems and its 5 protected areas (after [3]) ' ( D 0 ) ) 6 ;19: ;1=: ;1=:& 5.2 Blois left ban levee discretization 4 ( ) ( =;3 =2 & 5.3 Hydraulic data ' ) / ; ) & ( '02 ';222 '! ) & ) ) & ' ; ( 0 ) ( ( & () & Figure 17. Example of GIS visualization of CARDigues probabilities for the Loire flood T1000 on Blois levees (after [3]) ' ) ( ( 7

8 5.5 GIS presentation of Blois results 4. Figure 18. Example of a levee cross-section report edited with CARDigues tool (after [3]) 6 Conclusions and perspectives 7 References 8