Probabilistic reliability analysis of red river dike system protecting giao thuy nam dinh

Master Thesis Reassurances Name: Pham Viet Dinh Major: Sustainable Hydraulic Structures Student ID # 148ULG010 This is my thesis with the topic "Probabilistic reliability analysis of Red river dike system protecting Giao Thuy - Nam Dinh" under the guidance of Assoc Prof Mai Van Cong - Thuyloi University and Prof Radu Sarghiuta - University of Liege I hereby declare that this thesis is the scientific study of my own The results and data in the thesis are honest and no one published it in any other research Ha Noi, October 2016 Pham Viet Dinh Dinh Pham Viet – 148ULG010 Master Thesis Acknowledgments After a period of research, my master thesis with the topic "Probabilistic reliability analysis of Red river dike system protecting Giao Thuy - Nam Dinh" has been completed with the enthusiastic help of lecturers, friends, colleagues and my family To obtain results as today, I would like to express deep gratitude to the Assoc Prof Mai Van Cong from Thuyloi University and Prof Radu Sarghiuta from University of Liege those who were enthusiastic to guide and provide knowledge, documentation, scientific information as well as contribute valuable comments during the implementation of this thesis I also sincerely thank the help, the assistance in terms of expertise and experience of the teachers teaching in class, undergraduate and postgraduate training office; classmate in Thuyloi University and all my family, friends have motivated, inspired, create favorable conditions in all aspects to completing this thesis In the process of implementation of the thesis, due to the time and limited knowledge, there are surely unavoidable mistakes, so I wish to receive the comments of teachers, colleagues to help me improve knowledge in terms of learning and researching Sincere thanks! Ha Noi, October 2016 Pham Viet Dinh Dinh Pham Viet – 148ULG010 Master Thesis Table of contents Chapter 1: General introduction 1.1 Reasonable of this study 1.2 General information 1.3 International related research applications 1.4 Present situation of flood risks in Vietnam 1.5 Study objectives 1.6 Study approach Chapter 2: Boundary conditions & description of study area 2.1 Description of dike systems in Vietnam 2.2 Influence factors 2.2.1 The influence of hydrology 2.2.2 The influence of the tide 2.2.3 The influence of irrigation planning, traffic and construction 2.2.4 The influence of the protected area 10 2.2.5 The influence of other factors 10 2.3 Natural conditions 11 2.3.1 Location 11 2.3.2 Topographical characteristics 11 2.3.3 Hydrology 12 2.3.4 Climatic condition 12 2.4 Present situations of Huu Hong river dikes 13 2.5 Practical issues in application of the standard criteria and norms: 17 2.6 Overview of traditional design methods: 17 2.6.1 Background information 17 Dinh Pham Viet – 148ULG010 Master Thesis 2.6.2 Shortcoming in traditional design methods 19 2.7 Overview of probabilistic design method 19 2.7.1 General background 19 2.7.2 Historical development of probabilistic design method in the world 20 2.7.3 The approach of the method of probabilistic design 21 2.8 Conclusion chapter 21 Chapter 3: Safety assessment & reliability analysis of Huu Hong river dike 23 3.1 Background theory 23 3.2 Theoretical basis 24 3.2.1 Risk analysis 24 3.2.2 Reliability analysis of components in system 27 3.2.3 Mathematical basis of probabilistic design 28 3.2.4 Reliability analysis of system 36 3.3 Application of the probabilistic design in reliability of river dike system of the Huu Hong river dike 37 3.3.1 Case study: Safety assessment of existing river dike system in Giao Thuy district 38 3.3.2 Possible failure mechanisms of the river dike 39 3.3.3 Fault Tree Analysis 46 3.4 Conclusion chapter 46 Chapter 4: Application of probabilistic reliability analysis to assess safety of Huu Hong river dike system 48 4.1 Failure mechanisms to consider 48 4.1.1 Overflowing mechanism 48 4.1.2 Instability revetment mechanism 51 4.1.3 Scouring mechanism at dike toe 54 4.1.4 Piping mechanism 59 Dinh Pham Viet – 148ULG010 Master Thesis 4.1.5 Inner slope instability mechanism 63 4.1.6 Fault Tree Analysis 65 4.2 Establishing fragility curve 68 4.3 Conclusion chapter 72 Chapter 5: Conclusions and recommendations 73 5.1 Achieved results 73 5.2 Existing problems 74 5.3 Recommendations 74 5.4 Further research directions 74 References 76 Appendix 77 Parameters and documentation used to calculate for the Huu Hong river dike 77 Appendix 86 Result of probabilistic reliability analysis 86 Dinh Pham Viet – 148ULG010 Master Thesis List of figures Figure 2-1: Storms, natural disasters affect the coastal areas in Vietnam Figure 2-2: Administrative maps of Nam Dinh province 11 Figure 2-3: Location of Nam Dinh province on the map (from google map) 13 Figure 2-4: Overall system map dikes in Giao Thuy district - Nam Dinh province 14 Figure 2-5: Representative cross-section of Huu Hong river dike 15 Figure 2-6: Several photos of current situation of Huu Hong dike 16 Figure 3-1: Framework of risk analysis (CUR 141 – 1990) 26 Figure 3-2: Reliability function is shown in the plane RS 28 Figure 3-3: Definition of the probability of failure and the reliability index 28 Figure 3-4: Diagram of failure analysis of serial system and parallel system 37 Figure 3-5: Diagram of flood defense system of Huu Hong river dike – Giao Thuy district – Nam Dinh province 39 Figure 3-6: The failure mechanisms can occur in river dikes (CUR/TAW 1995) 40 Figure 3-7: Overflowing scheme 41 Figure 3-8: Instability revetment scheme 42 Figure 3-9: Scouring mechanism at dike toe scheme 43 Figure 3-10: Rupturing scheme Figure 3-11: Sand flowing scheme 44 Figure 3-12: Slope sliding scheme 45 Figure 3-13: Fault Tree diagram of flood defenses system – Huu Hong dikes 46 Figure 4-1: Real measured data of dike crest level 49 Figure 4-2: Distribution of dike crest level based on real measured data by using BESTFIT software 49 Figure 4-3: Real measured data of flood water level 50 Dinh Pham Viet – 148ULG010 Master Thesis Figure 4-4: Distribution of flood water level based on real measured data by using BESTFIT software 50 Figure 4-5: Influence of random variables to the overflowing mechanism 51 Figure 4-6: Influence of random variables to instability revetment mechanism 54 Figure 4-7: Real measured data of flood flow 56 Figure 4-8: Distribution of flood flow by using BESTFIT software 57 Figure 4-9: Influence of random variables to scouring mechanism at dike toe 58 Figure 4-10: Real measured data of upstream water level 60 Figure 4-11: Distribution of upstream water level based on real measured data by using BESTFIT software 60 Figure 4-12: Influence of random variables to the rupturing mechanism 62 Figure 4-13: Influence of random variables to sand flowing mechanism 63 Figure 4-14: Results of inner sliding stability by using Geostudio 2007 software 64 Figure 4-15: Diagram of Fault Tree Analysis for Huu Hong river dike system 66 Figure 4-16: Result of failure probability after using OpenFTA software 67 Figure 4-17: Graph of the iterative period with the highest water level at Ba Lat hydrology station 69 Figure 4-18: Fragility curve of correlation between Pf system and FWL 71 Figure 6-1: Iterative period according to highest water level at Hon Dau, Ba Lat hydrology station 78 Figure 6-2: Diagram of height of wave 81 Figure 6-3: Figure A1- Appendix A1 - TCVN 8421-2010 – Graph of determining wave factors causing by the wind in deep water and shallow water 82 Figure 6-4: Figure A2- Appendix A1 - TCVN 8421-2010 – Graph of determining coefficient k i 83 Figure 6-5: Result of inner sliding stability by using Geostudio 2007 software 85 Figure 6-6: Result of overflowing mechanism in case FWL = 3.62m 86 Dinh Pham Viet – 148ULG010 Master Thesis Figure 6-7: Result of instability revetment mechanism in case FWL = 3.62m 86 Figure 6-8: Result of scouring mechanism at dike toe in case FWL = 3.62m 87 Figure 6-9: Result of rupturing mechanism in case FWL = 3.62m 87 Figure 6-10: Result of sand flowing mechanism in case FWL = 3.62m 88 Figure 6-11: Result of inner slope instability mechanism in case FWL = 3.62m 88 Figure 12: Diagram of Fault Tree Analysis in case FWL = 3.62m 89 Figure 6-13: Result of overflowing mechanism in case FWL = 2.0m 91 Figure 6-14: Diagram of Fault Tree Analysis in case FWL = 2.0m 91 Dinh Pham Viet – 148ULG010 Master Thesis List of tables Table 4-1: List of random variables according to the overflowing mechanism 50 Table 4-2: The probability of the failure and the influence coefficient of the random variables to the overflowing mechanism 51 Table 4-3: List of random variables according to the instability revetment mechanism 53 Table 4-4: The probability of the failure and the influence coefficient of the random variables to the instability revetment mechanism 53 Table 4-5: List of random variables according to the scouring mechanism at dike toe 57 Table 4-6: The probability of the failure and the influence coefficient of the random variables to the scouring mechanism at dike toe 58 Table 4-7: List of random variables according to the piping mechanism 61 Table 4-8: The probability of the failure and the influence coefficient of the random variables to the rupturing mechanism 61 Table 4-9: The probability of the failure and the influence coefficient of the random variables to the sand flowing mechanism 62 Table 4-10: The probability of the failure of the inner slope instability mechanism 64 Table 4-11: Results of failure probability of Huu Hong river dike 65 Table 4-12: Table of the iterative period with the highest water level at Ba Lat hydrology station 69 Table 4-13: Probabilistic calculation with difference value of FWL 70 Dinh Pham Viet – 148ULG010 Master Thesis Chapter 1: General introduction 1.1 Reasonable of this study Vietnam has about 3260 km of coastline, mainly consists of coastal lowland is protected by a sea dike system, natural dunes, and mountains More than 165 km of coastline in the Red River delta, populated areas where there are significant changes and dynamic impact destroyed with intense frequently from the sea (storms, changes in sea level, flow, etc.) Therefore, dikes are important structures which are built, maintained and protected through generations to prevent flood water, sea water and to protect the lives and property of the government and people, to promote social and economic Social development, linked to national defense, security, sovereignty, and national benefits The process of formation and development of the dike system always linked to the life and productive activities of the people from generation to generation Most dikes are now combined as roads in which many dikes pass through tourist areas, urban areas and residential areas During the development processes, requirements for dike system as well as the direct impacts of human on the dike are growing and increasing in complex evolution In recent years, natural disasters and climate changes in Vietnam have had more abnormal and complex In particular, storms and floods are two types of natural disasters which frequently occur and cause the most severe consequences, especially in the area of coastal estuaries However, most of the system of dikes and storm prevention, flood prevention existing today in Vietnam is designed and constructed based on the experience accumulated from many generations and applied safety standards which only suit economic situation - engineering conditions of the country in some decades ago Before the adverse effects of weather variations and changes in an abnormal phenomenon of natural disasters due to climate change, coupled with the requirement to ensure a higher level of safety of the protected areas to serve the sustainable development of economic - society, the research and development applications in reliability theory of optimal design system against storms, floods and on this basis build up the safety assessment criteria according to reliability theory and construction process safety assessment system of dikes in estuaries and coastal areas according to theory of reliability in Vietnam condition at the present time and the future is necessary Pham Viet Dinh – 148ULG010 Master Thesis 15 Case FWL = 4.6 m Pham Viet Dinh – 148ULG010 117 Master Thesis Pham Viet Dinh – 148ULG010 118 Master Thesis 16 Case FWL = 4.8 m Pham Viet Dinh – 148ULG010 119 Master Thesis Pham Viet Dinh – 148ULG010 120 Master Thesis 17 Case FWL = 5.0 m Pham Viet Dinh – 148ULG010 121 Master Thesis Pham Viet Dinh – 148ULG010 122 Master Thesis 18 Case FWL = 5.2 m Pham Viet Dinh – 148ULG010 123 Master Thesis Pham Viet Dinh – 148ULG010 124 Master Thesis 19 Case FWL = 5.4 m Pham Viet Dinh – 148ULG010 125 Master Thesis Pham Viet Dinh – 148ULG010 126 Master Thesis 20 Case FWL = 6.0 m Pham Viet Dinh – 148ULG010 127 Master Thesis Pham Viet Dinh – 148ULG010 128 Master Thesis 21 Case FWL = 7.0 m Pham Viet Dinh – 148ULG010 129 Master Thesis Pham Viet Dinh – 148ULG010 130 Master Thesis 131 Summarizing all results we have a table as follow: No 10 11 12 13 14 15 16 17 18 19 20 21 m Reliability index α Failure probability of overflowing mechanism P(Z