Reliabilty analysis of the red river dike system in vietna

OF THE R ELIABILITY ANALYSIS R ED R IVER D IKE SYSTEM IN V IET N AM OF THE R ELIABILITY ANALYSIS R ED R IVER D IKE SYSTEM IN V IET N AM Proefschrift ter verkrijging van de graad van doctor aan de Technische Universiteit Delft, op gezag van de Rector Magnificus prof ir K C A M Luyben, voorzitter van het College voor Promoties, in het openbaar te verdedigen op woensdag oktober 2014 om 12:30 uur door Pham Q UANG TU civiel ingenieur geboren te Ha Nam, Viet Nam Dit proefschrift is goedgekeurd door de promotoren: Prof drs ir J.K Vrijling Prof dr ir P H A J M van Gelder Samenstelling promotiecommissie: Rector Magnificus, Prof drs ir J.K Vrijling, Prof dr ir P H A J M van Gelder, Prof dr T M Thu, Prof dr ir M Kok, Dr ir K J Bakker, Ir M R Tonneijck, Dr ir W Kanning Prof dr C Jommi, voorzitter Technische Universiteit Delft, promotor Technische Universiteit Delft, promotor Water Resources University of Viet Nam Technische Universiteit Delft Technische Universiteit Delft Royal HaskoningDHV Colorado School of Mines/Deltares Technische Universiteit Delft, reservelid Keywords: Geotechnical reliability, flood defence, Red River dike, piping, uplift geotechnical engineering, hydraulic engineering Printed by: Ridderprint B.V., Ridderkerk, the Netherlands Front & Back: Red River Dike on the right bank in Ha Noi, by Pham Anh Tuan (2010) Cover layout by: Pham Anh Tuan Copyright © 2014 by Pham Quang Tu ISBN 978-90-5335-887-0 An electronic version of this dissertation is available at http://repository.tudelft.nl/ Propositions pertaining to the dissertation R ELIABILITY ANALYSIS OF THE R ED R IVER D IKE SYSTEM IN V IET N AM by Pham Quang T U Red River Dike safety is lower than expected, even in some so far undoubted locations (in this thesis) Ground conditions contribute greatly to uncertainty in the assessment of dikes A long duration flood might threaten the Red River dikes in the future when reservoirs are completed (in this thesis) The highest failure probability of a dike occurs in the next few hours after the flood peak (in this thesis) The reduction of seepage length can be used to predict the piping process during repeated and long duration floods (in this thesis) Integration of Hydraulic Engineering and Geotechnical Engineering is an extremely important and fertile research area Reliability-based analysis in Geotechnical Engineering is applicable in developing countries The particular climatological conditions and the geography of lakes and estuaries contribute to the success of the flood risk management in the Netherlands Flooding has been the issue of most concern since antiquity in the society of Viet Nam, as shown by the classical warning “thủy, hỏa, đạo, tặc” (the Vietnamese proverb):“flooding, firing, robbing, and invading” 10 The challenge of a PhD’s life is the same as that of learning a new sport but more interesting and beneficial These propositions are regarded as opposable and defendable, and have been approved as such by the supervisors prof drs ir J.K Vrijling and prof dr ir P H A J M van Gelder Stellingen behorende bij het proefschrift R ELIABILITY ANALYSIS OF THE R ED R IVER D IKE SYSTEM IN V IET N AM door Pham Quang T U De veiligheid van de Rode Rivier Dijk is lager dan verwacht, zelfs in sommige tot nu toe onbetwijfelde locaties (dit proefschrift) De grondgesteldheid draagt in grote mate bij tot onzekerheid bij de beoordeling van dijken Een langdurige hoogwatergolf zal in de toekomst, wanneer reservoirs zijn voltooid, een bedreiging vormen voor de Rode Rivier Dijk (dit proefschrift) De hoogste kans op het falen van een dijk treedt op na de piek van de hoogwatergolf (dit proefschrift) De verkorting van de kwellengte kan worden gebruikt om het pipings-proces tijdens herhaalde en langdurige overstromingen te voorspellen (dit proefschrift) Integratie van Waterbouwkunde en Geotechniek kan tot een uiterst belangrijk en vruchtbaar onderzoeksterrein leiden De op betrouwbaarheid gebaseerde analyse in de Geotechniek is toepasbaar in ontwikkelingslanden De bijzondere klimatologische omstandigheden en de geografie van meren en riviermondingen dragen bij aan het succes van het beheer van overstromingsrisico’s in Nederland Sinds de oudheid zijn overstromingen het grootste probleem geweest in de Vietnamese samenleving, hetgeen blijkt uit de klassieke waarschuwing “thủy, hỏa, đạo, tặc” (Vietnamees spreekwoord): " overstroming, brand, beroving en invasie " 10 De uitdaging van het leven van een PhD is dezelfde als die van het leren van een nieuwe sport, maar interessanter en heilzamer Deze stellingen worden opponeerbaar en verdedigbaar geacht en zijn als zodanig goedgekeurd door de promotoren prof drs ir J.K Vrijling en prof dr ir P H A J M van Gelder S UMMARY This dissertation synthesises the application of a probabilistic-based framework in geotechnical and hydraulic engineering, for the assessment of the Red River dikes in Viet Nam The study area promotes the probabilistic-based approach because of its typical natural conditions Lack of understanding of soil and water behaviours may lead to failures of engineering design, as is proven from practice This study is intended to fill part of these gaps Dikes along rivers often spread over the deltaic environment and its earthen structures are parts of a long civilian history, from hundreds to thousands of years Uncertainties of soil properties of the dike embankment and its foundation, and contribute to the probability of failure under a given water level To carry out an assessment of the safety of the flood defences, both a conventional approach and a reliability analysis may be applied The former relies on the factors of safety while the latter takes uncertainties of both water level (load) and soil properties (resistance) more explicitly into account The reliability-based framework proved its benefits in important projects and in dealing with large uncertainties in design This is demonstrated through the chapters in this thesis Firstly, the background information of the natural conditions, the socio-economic issues and the flood defences in the Red River Delta are presented in Chapter The topographic conditions and meteorological characteristics play an important role in the flood defence management of the Red River Delta Around 50% of the delta area is lower than m (above mean sea level) and the delta is partly surrounded by high mountains Consequently, under extreme weather conditions such as typhoons, fronts, and tropical depressions, flooding will affect the lowlands area On the other hand, the socio-economic issues indicate a fast growing economy of Viet Nam Hence, new requirements of higher safety standards for the flood defences seem advisable In fact, the flood defences in the Red River Delta have been established for hundreds of years and the safety standard has increased from a design water level of 1/5 years (in the Imperial period ∼ the 1890s) to 1/500 years (at the present) The current design water level is 13.4 m (above mean sea level) at the gauging station of Ha Noi, which will be routed to the dike stretches in the whole delta area Secondly, the analyses of the hydraulic boundary conditions are performed in Chapter with a detailed description of the Red River system and an evaluation of the hydraulic parameters for the reliability analysis The Red River is formed by three tributaries (the Da, Thao, and Lo River), and the maximum observed discharge was 37,800 m /s in August 1971 at Son Tay in the area of Ha Noi The reservoirs systems in the Da and Lo River significantly reduce the peak flood discharge in the delta area by a storage capacity of 8.5 billion cubic metres; as for instance in the flood with frequency of 1/500 years, the peak discharge will decrease approximately 40%, from 48, 500 m /s to 30, 000 m /s By doing so, the dike system may be severely loaded during a long duration flood of around 120 hours but the water level is lower than the original Another issue is the increasing trend of the water level at the same river discharge, which is due to the over expansion of residents in the flood plain, therefore the resulting probability of overflow will become higher in future if there are no measures to control such developments Thirdly, the probabilistic-based analysis framework and its application are treated in v vi S UMMARY Chapter and 5, including classification of ground conditions, model uncertainties, and spatial variability of soil parameters Currently, the calculation level (semi-probabilistic) has been embedded in the design codes while the calculation level (e.g FORM) and (e.g Monte Carlo simulation) are used for important projects or the calibration of the level design codes Soils properties and ground conditions are analysed by different approaches, either by classical statistics or by a probabilistic-based framework It is hoped to increase the engineer’s understanding about the use of probabilistic-based methods in practice To take examples, uplift and ground coefficient are analysed by using the model factor The former presents a physical-based model of uplift which was calibrated for the study area by field tests The latter discusses a new model of ground uncertainties (the ground coefficient - α) that represents the cumulative effects of the internal erosion process in both flood and dry season Moreover, an illustration of spatial estimation was performed on two data series of the top-layer thickness (with the distance of sampling of around 30 m and 200 m) The calculation results indicate a correlation between the scales of fluctuation and the distance of sampling It is expected that the mentioned theories and applications will be incorporated in Geotechnical Engineering and Flood Defences assessment, especially in Viet Nam Fourthly, the theory of reliability analysis of a river dike and its application in the Red River Dikes are discussed in Chapters and 7, where piping, overflow, and instability are considered under a long duration flood Probabilities of overflow are predicted to be high in the dike stretches of the Ha Tay area due to a lower design water level in the past Therefore, dike crests should be heightened to meet the same safety standards as that in the Ha Noi area To evaluate piping during a long duration flood, a model of seepage length reduction of piping with respect to time is developed from a basic principle: the internal erosion process depending on seepage gradient and ground conditions The proposed model, after calibrating by a historical dike failure in the study area, predicts an increase of the erosion length from 3% to 20% (the seepage length shortening from 100% to 97% or 80% respectively) in one typical flood wave, which leads to the cumulative effects of piping and internal erosion under the dike embankment On the other hand, the geotechnical instability is proven to be less affected during a long flood wave However, only homogeneous models of embankments are mentioned in this study It is suggested that in future research more attention should be given to the heterogeneity of dike embankments with regard to permeability Finally, by taking the length-effect into account, the probability of failure of dike stretches in the study area may significantly increase depending on its stretch length and the spatial variation of soil parameters, as for instance the total probability of failure of the dike system will jump from 21%-25% to 38%-47% (by without or/and with taking lengtheffect into account respectively) The findings of this research hope to contribute to a new understanding of Red River Dike safety in Viet Nam They also open up several research directions in the combined field of hydraulic engineering and geotechnical engineering, and widen the applications of probabilistic-based approaches in Viet Nam and developing countries S AMENVATTING In deze dissertatie wordt een synthese uitgevoerd van de toepassing van een op probabilistische methoden gebaseerd kader in de geotechniek en de waterbouwkunde, ten behoeve van de beoordeling van de betrouwbaarheid van dijken langs de Rode Rivier (in Vietnamees: Song Hong) in Viet Nam De toepassing van een probabilistische benadering is hier met name opportuun vanwege de typisch natuurlijke omstandigheden in dit onderzoeksgebied Een gebrekkig begrip van grond- en watercondities zou namelijk, zoals uit de praktijk gebleken is, tot mislukkingen in technische ontwerpen kunnen leiden Deze studie is bedoeld om een deel van deze lacunes te vullen Dijken langs rivieren strekken zich uit over de delta en dergelijke grondconstructies zijn deel van een lange civiele geschiedenis, van honderden tot duizenden jaren De onzekerheden in de grondeigenschappen van dijklichaam en fundering dragen bij aan de faalkans bij een bepaalde waterstand Om een inschatting te kunnen maken van de veiligheid van waterkeringen, worden vaak zowel een conventionele analyse als een betrouwbaarheidsanalyse toegepast De eerste, conventionele benadering verlaat zich op veiligheidsfactoren, terwijl de tweede methode onzekerheden in waterstanden (belasting) en grondeigenschappen (sterkte) in acht neemt Het op betrouwbaarheid gebaseerde toetsingskader heeft zijn nut al bewezen in belangrijke projecten en bij grote ontwerponzekerheden Deze benadering wordt in de hoofdstukken van deze dissertatie gedemonstreerd De achtergrondinformatie over de natuurlijke omstandigheden, de sociaaleconomische situatie en de waterkeringen in de regio wordt in hoofdstuk gepresenteerd De topografische condities en de meteorologische omstandigheden spelen een belangrijke rol in de hoogwaterbescherming van de Rode Rivier Delta Ongeveer 50% van de delta ligt lager dan meter (boven gemiddeld zeeniveau) en is gedeeltelijk omringd door hoge bergen Derhalve, onder extreme weersomstandigheden, zoals tyfoons, fronten en tropische depressies, zal het laaggelegen land door overstromingen getroffen worden Omdat de huidige sociaaleconomische situatie van Viet Nam echter op een snel groeiende economie duidt, lijken nieuwe eisen voor hogere veiligheidsnormen voor de hoofwaterbescherming daarom raadzaam In feite, in de honderden jaren van het bestaan van waterkeringen in de Rode Rivier Delta zijn de veiligheidsnormen al toegenomen van een ontwerpwaterhoogte van 1/5 jaar (in de imperiale periode ∼1890s) tot 1/500 jaar (2014) De huidige ontwerpwaterhoogte is 13.4 m (boven gemiddeld zeeniveau) bij het meetstation van Ha Noi, en wordt vervolgens naar alle dijken in de gehele delta doorberekend In hoofdstuk worden de hydraulische randvoorwaarden bepaald door een gedetailleerde beschrijving van het Rode Rivier systeem en een evaluatie van de hydraulische parameters voor de betrouwbaarheidsanalyse De Rode Rivier wordt gevormd door drie zijrivieren, de Da, de Thao en de Lo rivier, die samenkomen bij Son Tay in de omgeving van Ha Noi, waar in augustus 1971 een maximum debiet van 37,800 m /s werd geobserveerd De reservoirs in de Da en de Lo rivier hebben door een opslagcapaciteit van 8.5 miljard kubieke meter een reductie van de piekwaterafvoer in de delta tot gevolg, zoals bijvoorbeeld met betrekking tot de overstromingsfrequentie van 1/500 jaar, zal de piekafvoer verminderen met 40%, van 48,500 m /s tot 30,000 m /s Het gevolg hiervan kan zijn, dat het dijksysteem ernvii viii S AMENVATTING stig belast kan worden gedurende een langdurige hoogwaterstand van ongeveer 120 uur Een ander aspect is een toenemend waterniveau bij gelijkblijvende afvoer, als gevolg van bewoning in de hoogwaterbedding, welke, indien geen maatregelen worden getroffen, kan resulteren in een hogere waarschijnlijkheid van overstromen in de toekomst De beschrijving en toepassing van het op probabilistiek gebaseerde kader van analyse, inclusief de classificatie van grondcondities, modelonzekerheden en ruimtelijke variatie van grondparameters, wordt in hoofdstuk en behandeld Momenteel is het niveau berekeningsmodel ingebed in de ontwerpnormen, terwijl berekeningsniveau en gebruikt worden voor grote projecten of voor de kalibratie van de niveau ontwerpnormen Grondeigenschappen en bodemcondities worden op verschillende manieren geanalyseerd, namelijk met de klassieke statistische benadering, of met een probabilistisch gebaseerd kader Het is de hoopvolle verwachting dat er meer kennis zal ontstaan onder ingenieurs voor de toepassing van een probabilistische methode in het veld Als voorbeeld worden het opdrijven van de afdekkende laag aan de binnenzijde van de dijk en de grondcoëfficiënt geanalyseerd met gebruikmaking van een modelfactor Het eerste voorbeeld behelst een fysisch gebaseerd model van opwaartse druk welke in het studiegebied werd gekalibreerd door veldonderzoek Laatstgenoemd voorbeeld beschrijft een nieuw model van grondonzekerheid (grondcoëfficiënt - α), dat de cumulatieve effecten van het interne erosieproces in zowel het regen- als het droge seizoen vertegenwoordigt Bovendien werd een illustratie van ruimtelijke inschatting gemaakt voor twee dataseries van de bovenlaagdikte (met een steekproefafstand van ca 30m en 200m) De berekeningen geven een correlatie aan tussen de schaal van fluctuatie en de afstand tussen de metingen Het wordt verwacht dat de theorieën en hun toepassingen in de geotechniek en toetsing van waterkeringen, in met name Vietnam, geïncorporeerd zullen worden In hoofdstuk en wordt de theorie van de betrouwbaarheidsanalyse van een rivierdijk en de toepassing daarvan op de dijken van de Rode Rivier besproken; overstromen, instabiliteit en “piping” worden bekeken onder een langdurige hoogwaterstand De kans op overstromen wordt naar verwachting hoog in de dijkvakken in de omgeving van Ha Tay ten gevolge van een lagere ontwerpwaterstand in het verleden De kruinhoogte zou daarom verhoogd moeten worden om dezelfde veiligheidsstandaard als in het gebied rond Ha Noi te realiseren Om “piping” (zandvoerende wel) gedurende een langdurige hoogwaterstand te evalueren, wordt een model van kwellengtereductie als functie van de tijd ontwikkeld vanuit een basisprincipe: namelijk het interne erosieproces dat afhangt van de kwelgradiënt en grondeigenschappen Na de kalibratie van het falen van een dijk in het onderzoeksgebied voorspelt het voorgestelde model een toename in de lengte van erosie van 3% tot 20% (de lengte van de kwel respectievelijk verminder van 100% tot 97% of 80%) gedurende een typische vloedgolf Dit leidt tot een opeenstapeling van de effecten van “piping” en interne erosie onder de dijk Anderzijds wordt bewezen dat de geotechnische instabiliteit minder wordt bedreigd tijdens een langdurige afvoergolf In dit onderzoek zijn echter slechts homogene modellen van dijken bestudeerd De suggestie is dan ook dat in toekomstig onderzoek meer aandacht wordt geschonken aan de heterogeniteit van dijken met betrekking tot hun waterdoorlatendheid Tot slot, door het lengte-effect in acht te nemen, kan de waarschijnlijkheid van een dijkbreuk in het studiegebied aanzienlijk hoger blijken te zijn dan was aangenomen, afhankelijk van de lengte en de ruimtelijke variatie in grondparameters, zodat bijvoorbeeld de totale faalkans van het dijksysteem zal toenemen van 21%-25% (zonder lengte-effect) tot 38%-47% (met lengte-effect) De resultaten van dit onderzoek zullen hopelijk bijdragen tot een nieuw begrip van vei- 178 A PPENDIX I: D ECAY AND DELAY OF GROUNDWATER FLOW Consider a cyclic boundary conditions imposed to the aquifer: P = P o cos(ωat ), x = 0, ∀t (I.6) The harmonic solution is found by separation of variables, according to P = P(x) exp(i ωt ) (I.7) with corresponding boundary condition: P(0) = P (I.8) p = p(z) exp(i ωt ) (I.9) with corresponding boundary condition: p(0) = P(x) (I.10) q o = qo exp(i ωt ) (I.11) These equations can be solved for the underbar variables Separation of the real part and imaginary part of the solution results in the response with respect to the real and imaginary part of exp(i ωt ) = cos(i ωt ) + i sin(i ωt ) This procedure yields for the aquitard Equation (I.2), assuming p = for z → ∞(relatively thick aquitard) p = P(x) exp −z iω C (I.12) Hence, the leakage flux at the interface becomes, with Equations (I.3) and (I.12): γqo = −k ∂p ∂z = Pk iω exp −z C iω C (I.13) In the onther hand, we have: I 2δ iω δ δ(1 − i ) = = = C d d i d (1 + i ) (I.14) iω δ = P (1 − i ) exp −z C C iω C (I.15) δ = d ω 2C (I.16) So that: γqo = P d δ(1 − i ) exp −z C d with where, C represents the hydraulic resistance of the aquitard; and C = d /k , and d is the (relevant) thickness of the aquitard (it is the zone where, the response is noticed, significantly smaller than the real aquitard thickness) A PPENDIX I: D ECAY AND DELAY OF GROUNDWATER FLOW 179 Substitution of Equation (I.13) in the aquifer Equation (I.1) yields, after some elaborations with an assumption: P = for x → ∞ (relatively wide aquifer), we have: P = P o exp − with λi ω = x , λi ω iω C (I.17) + (1 + i ) λδ2 = λ δ(i β + (1 + i )) (I.18) The cyclic leakage factor λi ω can be determined as follows 1+ia = , λi ω λω 1 with = δ (1 + β2 ) + λω λ (I.19) arctan(1 + β) , arctan(1 + β) and λ = C kD, and a = tan , ω ωλ2 , and δ = d and β = Cδ 2C 0.25 cos (I.20) (I.21) (I.22) The solution for P in sand layer is the real part of this equation: P = P exp(i ωt ) = P o exp i ωt − x λi ω (I.23) So that, P = P o exp − x ax cos ωt − λω λω (I.24) The corresponding solution for the consolidation in the aquitard becomes, by evaluating Equation (I.12) and (I.7) with the boundary condition (I.6): p = P o exp − x δz ax δz cos ωt − − − λω d λω d (I.25) Solution (I.24) and (I.25) show that the cyclic boundary pressure at x = is conveyed into the aquifer system with an amplitude decay exp(−x/λω ) and a retardation (delay) [ax/(λω ω)] for the aquifer pressure and an additional amplitude decay exp(−zδ/d ) and additional retardation time (delay)[−zδ/(d ω)] for the aquitard pressure I J O BSERVED P HENOMENA D URING F LOOD S EASONS IN THE R ED R IVER D IKE The observed data come from different Dike Brigades in the area of Ha Noi in period the 1970s till now (DDMFC, 2009) Table J.1: Summary of number of observed phenonmena on the Red River dike from Km25+700 to Km110+400 Station 25+700 26+000 26+700 27+000 29+000 29+200 29+400 29+600 29+800 30+200 31+100 31+400 31+500 31+600 31+720 31+800 31+900 31+950 31+980 32+000 Observed phenonmena Sand boils Slope failure Termite 1 1 1 1 1 4 1 continued on next page (2) is number of observations of each phenomenon 181 182 J A PPENDIX J: O BSERVED PHENOMENA DURING FLOOD SEASONS IN THE R ED R IVER continued from previous page Station Observed phenonmena Sand boils Slope failure Termite 32+100 32+200 32+300 32+350 32+390 32+400 32+430 32+450 32+500 32+600 32+650 32+700 32+800 10 32+850 32+900 32+980 33+000 33+100 33+400 33+600 33+700 33+800 33+900 34+000 34+100 34+200 34+300 34+400 34+800 34+900 35+300 35+600 35+700 36+100 43+000 43+600 44+200 44+500 46+300 46+600 48+000 48+690 50+350 52+000 1 52+100 52+650 52+700 53+500 53+750 60+000 60+360 continued on next page (2) is number of observations of each phenomenon A PPENDIX J: O BSERVED PHENOMENA DURING FLOOD SEASONS IN THE R ED R IVER continued from previous page Station Observed phenonmena Sand boils Slope failure Termite 60+500 61+700 61+850 62+480 62+550 62+670 64+100 70+500 71+200 72+800 72+900 72+950 73+000 73+100 73+200 73+300 73+350 73+400 74+400 74+750 74+900 76+300 76+600 76+900 77+150 77+400 77+500 77+800 78+100 78+300 78+500 78+700 78+800 79+400 80+000 81+000 81+150 81+200 81+450 81+500 81+600 81+700 81+800 81+900 82+000 82+500 82+700 82+800 82+900 83+900 84+200 continued on next page (2) is number of observations of each phenomenon 183 J 184 J A PPENDIX J: O BSERVED PHENOMENA DURING FLOOD SEASONS IN THE R ED R IVER continued from previous page Station Observed phenonmena Sand boils Slope failure Termite 84+300 85+000 85+300 85+350 85+400 85+500 85+600 85+800 85+900 86+000 86+100 86+300 1 86+500 86+600 87+100 87+300 87+400 87+600 88+000 88+100 88+200 88+350 88+400 88+500 88+600 89+300 89+400 89+600 90+100 90+200 90+300 91+200 91+300 91+400 92+000 92+100 93+300 93+400 93+500 93+800 93+900 94+000 94+150 94+500 94+525 94+600 94+800 94+970 95+050 95+200 95+500 continued on next page (2) is number of observations of each phenomenon A PPENDIX J: O BSERVED PHENOMENA DURING FLOOD SEASONS IN THE R ED R IVER 185 continued from previous page Station Observed phenonmena Sand boils Slope failure Termite 95+800 96+100 96+200 96+300 96+350 96+400 96+600 96+700 96+900 97+000 97+050 97+100 98+000 98+100 98+250 98+400 98+430 99+000 99+500 99+900 100+000 100+600 101+030 101+100 101+200 101+400 101+600 101+650 101+700 102+100 102+600 104+000 104+800 110+400 J A CKNOWLEDGEMENTS Doing the PhD research has been one of the most challenging things in my life, but it has also been interesting and relaxing; similarly when I started to play football again in Delft, nearly twenty years after playing in secondary school This doctoral dissertation is my own work, but I received so much support and help from people around me, which gives me a chance to write these acknowledgements Overall, I would like to express my deepest gratitude to prof drs ir J.K Vrijling and prof dr ir P.H.A.J.M van Gelder, my promoters, for their continuous guidance and encouragement Han interviewed and accepted me to be his PhD student, and also has given me a completely freedom PhD life, from our first discussion in Ha Noi and throughout these past four years in Delft; his sharp and critical comments helped me to continuously improve the contents of my thesis All the discussions with Pieter did not need to be long but have been very productive; his broad knowledge in statistics, probabilistics and their applications in hydraulic engineering motivated me to go further in this field Sometimes, one of the Pieter’s suggestions took me for weeks to really understand; it was hard but in the end I have benefited a lot I am also grateful to my graduation committee members: prof dr ir M Kok, prof dr T M Thu, dr ir K.J Bakker, dr ir Wim Kanning, ir M R Tonneijck, and prof dr C Jommi for their critical comments and suggestions to improve the manuscripts Special thanks I would like to address to prof dr Trinh Minh Thu for his influence on my academic career, encouraging me to this research and also very helpful discussions during my research in Viet Nam I would like to acknowledge the financial support from CICAT, the Valorisation center, and the Section of Hydraulic Engineering, and give especial thanks to dr Paul Althus, ms Marjan Kreijns, ms Veronique van der Vast, prof dr ir S.N Jonkman and prof dr ir M Stive for their unconditional support This work would not be success without the support from people and institutions in Viet Nam and the Netherlands On the Viet Nam side, I am grateful to prof Ha Van Khoi, dr Bui Van Truong, and ass prof Mai Van Cong, from WRU, for their fruitful discussions and support My research initiated from a recommendation in the research of prof Khoi, whose results are partly integrated in this dissertation Dr Truong shared with me the interests from his PhD research as well as its results His support and guidance are highly acknowledged All the discussions with Dr Cong are helpful His friendship and support are also appreciated Other colleagues from WRU who I would like to give my gratitude including: prof Pham Ngoc Quy, dr Hoang Viet Hung, ass prof Pham Huu Sy, msc Nguyen Dinh Khiem, dr Ngo Le An, prof Nguyen Cong Man, ass prof Vu Minh Cat, and my colleagues in the Geotechnical division of WRU for their discussions and support during my research Dr Tran Van Tu (IGS-VAST), prof Pham van Ty, dr To Xuan Vu (HUMG), dr Nguyen Thi Phuong Nam (TVU/UVA), MSc Pham Van Dong (DDMFC-Ha Noi), the Dike-Brigades in the areas of Ha Noi, MSc Do Anh Chung (WIP-VAWR), the DDMFC - MARD, and TEDI are also gratefully thanked On the Netherlands side, I would like to express my great gratitude to prof dr ir Frans 187 188 A CKNOWLEDGEMENTS Barends, drs Mariette van Tilburg, dr ir Wim Kanning, dr ir Sellmeijer, ir Gerrit Jan Schiereck, ir Joop Weijer, dr ir Timo Schweckendiek, Jame Salmon (TU Delft), dr Rien Dam, ir Ed Calle (Deltares), prof ir A.C.W.M Vrouwenvelder and dr R.B.J Brinkgreve (Plaxis) Prof Barends gave me free lessons about groundwater flow and consolidation; his mathematical talent and his encouragement helped me to find the analytical solutions for some problems; I deeply express my gratitude to him I greatly appreciate Mariette she shortened the final period of my PhD, and thank for her enthusiastic work and critical comments on the uses of the English language; my writing has improved a lot I would like to thank Wim, for his discussions during my beginning period in Delft and for the useful comments in the last period Gerrit Jan Schiereck made my feeling of homesickness less by a lunch at his home and a tour around the Dordrecht city, when I first visited Delft He also guided us in so many field trips with the Vietnamese delegations; I very much appreciate all his help Thanks to Timo, my office-mate in the last one and a half year, for his helpful and productive discussions The support from the staff in the Department of Hydraulic Engineering is also highly acknowledged: Judith, Agnes, Inge, Chantal, Otti and Mark The Vietnamese community in Delft (VCID), which I joined in parties, BBQs, sightseeing, games, etc.; QTFC - a small football club - where I started learning football again after a very long time It would take pages to recall all of my friends who have been part of my PhD life: let me list your name in my heart and wish you all happiness and success I love you all The PhD community in the Hydraulic Engineering Section, in which each of the written story, taken by each PhD student, comes from different parts of the world in terms of living culture, scientific background, research target, etc Each coffee break, birthday cake, seminar, colloquium or outing helps us closed together and refreshes after the pressured working hours I look forward seeing you again in Delft or somewhere else Last but not least, to Thu Hang - my wife, your sacrifices, your patience, and your faithful love have helped me to reach this day; I wish to dedicate this dissertation to you To my princesses Miu and Chip, I am back soon, you not have to worry any more how long I will be far from you I am grateful to my parents and my parents-in-law for their help during my absence Going to the university was a dream of my brother and sister, who did not have chances to it, now I give this book to you Pham Quang TU Delft, June 2014 L OI CAM ON Làm nghiên cứu sinh thử thách lớn đời đến thời điểm thú vị thoải mái, tương tự học đá bóng Delft sau gần 20 năm từ trung học sở Luận án cơng trình nghiên cứu riêng tôi nhận nhiều giúp đỡ trợ giúp từ người quanh tơi, tất điều cho tơi hội để viết nên lời cảm ơn ngày hôm Trên tất cả, tơi muốn bày tỏ lịng biết ơn sâu sắc đến thầy hướng dẫn: giáo sư J.K Vrijling giáo sư P.H.A.J.M van Gelder dắt động viên suốt thời gian làm nghiên cứu Giáo sư Han trực tiếp vấn chấp thuận nghiên cứu sinh ông; ông cho sống nghiên cứu sinh hoàn toàn tự do, từ lần đầu gặp gỡ Hà Nội đến khoảng thời gian năm nghiên cứu Delft Những ý kiến sắc sảo nghiêm khắc ông giúp chỉnh sửa nhiều nội dung luận án Tất thảo luận với giáo sư Pieter không cần dài hiệu quả; kiến thức uyên thâm ông lĩnh vực thống kê, xác suất ứng dụng thủy công tạo cảm hứng để sâu vào nghiên cứu lĩnh vực Nhiều khi, gợi ý Pieter làm nhiều tuần để thực hiểu nghĩa; điều khó khăn tơi học nhiều sau lần Tôi biết ơn hội đồng chấm luận văn gồm: giáo sư M Kok, tiến sỹ K.J Bakker, tiến sỹ Wim Kanning, kỹ sư M R Tonneijck, giáo sư C Jommi nhận xét góp ý họ để tơi chỉnh sửa luận văn Lời cảm ơn đặc biệt muốn dành cho phó giáo sư Trịnh Minh Thụ ảnh hưởng ông tới công việc tôi, ông thường xuyên động viên trình nghiên cứu thảo luận hữu ích khoảng thời gian thu thập số liệu Việt Nam Tơi muốn cảm ơn hỗ trợ tài CICAT, trung tâm Valorisation Section Hydraulic Engineering, đặc biệt cảm ơn tiến sỹ Paul Althus, cô Marjan Kreijns, cô Veronique van der Vast, giáo sư S.N Jonkman giáo sư M Stive giúp đỡ vô tư họ Luận án thành công khơng có giúp đỡ bạn bè, đồng nghiệp từ quan Việt Nam Hà Lan Về phía Việt Nam, tơi biết ơn giáo sư Hà Văn Khối, tiến sỹ Bùi Văn Trường phó giáo sư Mai Văn Công (trường ĐHTL) giúp đỡ hỗ trợ họ Nghiên cứu kiến nghị đề tài giáo sư Khối, số kết nghiên cứu ông sử dụng nghiên cứu Tiến sỹ Trường chia sẻ điểm kết nghiên cứu anh Sự giúp đỡ hướng dẫn anh xin trân trọng cảm ơn Những thảo luận với tiến sỹ Cơng hiệu Tình cảm thân thiết giúp đỡ anh xin ghi nhận Những thầy cô, đồng nghiệp từ trường ĐHTL, muốn bày tỏ lòng biết ơn gồm: giáo sư Phạm Ngọc Quý, tiến sỹ Hồng Việt Hùng, phó giáo sư Phạm Hữu Sy,thạc sỹ Nguyễn Đình Khiêm, tiến sỹ Ngơ Lê An, giáo sư Nguyễn Cơng Mẫn, phó giáo sư Vũ Minh Cát thầy cô thuộc môn Địa kỹ thuật, khoa Cơng trình thảo luận, giúp đỡ suốt thời gian 189 190 L OI CAM ON làm nghiên cứu Tiến sỹ Trần Văn Tư (Viện Địa chât - Viện Khoa học Việt Nam), giáo sư Phạm Văn Tỵ, tiến sỹ Tô Xuân Vu (trường ĐH Mỏ - Địa chất), tiến sỹ Nguyễn Thị Phương Nam (TVU/UVA), thạc sỹ Phạm Văn Đông (Chi cục đê điều Hà Nội), hạt quản lý đê thuộc địa bàn Hà Nội, thạc sỹ Đỗ Anh Chung (Viện phịng trừ mối bảo vệ cơng trình - Viện khoa học Thủy Lợi Việt Nam), Phòng quản lý đê - Tổng cục Thủy Lợi Tổng công ty Tư vấn Thiết kế GTVT (TEDI) xin trân trọng cảm ơn Về phía Hà Lan, tơi muốn bày tỏ lịng biết ơn tới giáo sư Frans Barends, bà Mariette van Tilburg, tiến sỹ Wim Kanning, tiến sỹ Sellmeijer, ông Gerrit Jan Schiereck, ông Joop Weijer, tiến sỹ Timo Schweckendiek, ông Jame Salmon (TU Delft), tiến sỹ Rien Dam, ông Ed Calle (Deltares), giáo sư A.C.W.M Vrouwenvelder tiến sỹ R.B.J Brinkgreve (Plaxis) Giáo sư Barends trực tiếp giảng cho phần dòng thấm nước đất cố kết; kiến thức toán học uyên thâm động viên ông giúp đưa lời giải cho số vấn đề luận văn, biết ơn ông nhiều Tôi vô cảm kích với bà Mariette - bà rút ngắn thời gian cuối giúp phần chỉnh sửa tiếng Anh với cách làm việc hiệu nhận xét khắt khe, nhờ phần viết tiếng anh cải thiện đáng kể Tôi muốn cảm ơn Wim Kanning thảo luận giai đoạn đầu sang Delft ý kiến giai đoạn cuối Gerrit Jan Schiereck xua cảm giác nhớ nhà lần đầu đến Delft bữa cơm thân mật nhà ông chuyến chơi vòng quanh thành phố Dodrecht - nơi ơng Ơng cịn dẫn chúng tơi nhiều chuyến thăm quan cơng trình có đồn Việt Nam sang cơng tác Tơi cảm kích giúp đỡ ông Tôi muốn cảm ơn Timo, bạn phòng năm rưỡi cuối cùng, giúp đỡ thảo luận hiệu Sự giúp đỡ đồng nghiệp Department of Hydraulic Engineering cảm ơn sâu sắc là: Judith, Agnes, Inge, Chantal, Otti Mark Cộng đồng Việt Nam Delft (VCID) nơi thường tham dự bữa tiệc, BBQ, buối dã ngoại trò chơi ; QTFC - câu lạc bóng đá nhỏ nơi tơi bắt đầu tập chơi lại bóng đá sau khoảng thời gian dài Sẽ khoảng vài trang để kể hết tên bạn người môt phần sống NCS năm Delft: để liệt kê tên bạn tim, cầu chúc tất người hạnh phúc thành công Tôi yêu quý tất người Cộng đồng NCS Hydraulic Engineering Section, nơi mà câu chuyện kể NCS đến từ vùng khác giới, phương diện văn hóa, chun mơn nghiên cứu, mục đích sống Mỗi buổi cà phê giải lao, ăn bánh sinh nhật, seminar, hội thảo giúp gần xua mệt mỏi sau làm việc căng thẳng Tôi mong gặp lại bạn Delft nơi Cuối khơng phải nhất, dành cho Thu Hằng - vợ tơi, hy sinh, kiên nhẫn tình yêu em giúp tơi có ngày Tơi ước dành cho em tất cơng trình Dành cho hai công chúa ba Miu Chíp, ba rồi, khơng phải lo lắng ba xa thêm khoảng thời gian Con biết ơn bố mẹ hai bên gia đình giúp đỡ khoảng thời gian vắng Vào đại học ước mơ anh trai chị gái tơi, người khơng có hội để làm việc đó, tơi muốn dành sách cho họ Pham Quang TU Delft - Ha Lan, 6/2014 C URRICULUM V ITỈ Pham Q UANG TU 06-09-1978 Born in Ha Nam, Viet Nam E DUCATION 2010-2014 PhD candidate Hydraulic Structure and Flood Risk Group Delft University of Technology, the Netherlands 2004-2007 MSc Engineering Geology Ha Noi University of Mining and Geology, Viet Nam (HUMG) Thesis: Slope stability analysis of the highway No7, from Km120-Km225 in Nghe An, Viet Nam Promotor: Prof dr Pham Van Ty 1996-2000 Bachelor Engineering Geology (with honour) Ha Noi University of Mining and Geology Thesis: Study on stability of the Tuyen Quang reservoir’s bank Promotor: Prof dr Pham Van Ty 1993-1996 Binh Luc A high school, Ha Nam, Viet Nam P ROFESSIONAL E XPERIENCE since 2007 Lecturer Geotechnical Division Water Resources University of Viet Nam (WRU) 2000-2007 Consultant Engineer on roadway and railways embankment and its foundation Transport Investment and Construction Consultant Company, Viet Nam (TRICC) AWARD 2000 Best student in the research competition at HUMG 191 ... details The Thao River is the main tributary of the Red River with a total basin area of 52, 000 km of which around 70% of the basin area is in the Yunnan province of China, see Figure 3.1 The river. .. Nam Dinh, Thai Binh, Hai Duong, V The total area of eleven provinces in the RRD is around 21, 000 km including the mountain areas of Quang Ninh and Ninh Binh provinces In the yearbook of the General... risk in the RRD, includes the reforesting in the upper basins, the constructing dams and reservoirs to store flood water, the strengthening of dikes, and the raising of public awareness of flood