The Netherlands Delta Project Author(S): Ian Watson and Charles W

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State of the Art in Storm-Surge Protection: The Netherlands Delta Project Author(s): Ian Watson and Charles W. Finkl Jr. Source: Journal of Coastal Research, Vol. 6, No. 3 (Summer, 1990), pp. 739-764 Published by: Coastal Education & Research Foundation, Inc. Stable URL: http://www.jstor.org/stable/4297737 . Accessed: 06/04/2013 15:43

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State of the Art in Storm-Surge Protection: The Netherlands Delta Project IanWatson and Charles W. Finkl, Jnr. Departmentof Geology FloridaAtlantic University BocaRaton, FL 33431,USA

ABSTRACT

Watson,I. and Finki,C.W., Jnr.,1990. State of the art in storm-surgeprotection: The NetherlandsDelta Project.Journal of CoastalResearch, 6(3), 739-764.Fort Lauder- sO00000 dale ISSN0749-02080. ,Il .* (Florida). A multi-billiondollar complex of coastalconstruction protects the delta-estuarine region of the south-westNetherlands from a repeatof the 1953storm-surge flooding that killed 1835.Eight documented storm-surge flood disasters date back to 1717.The DeltaProject becameeffective in termsof flood protectionin 1986,but sectionsof it are still under construction.One of the world'sgreatest civil-engineering projects, its 11 majorand multiplesecondary components have the functionof (1) closingoff threemain estuaries whichshorten the coastlineby approximately720 km, (2) creatinga non-tidalwaterway, the Scheldt-Rhinelink, which facilitates inland shipping between Antwerp and Rotter- dam (120 km), two of the largest ports in the world, and (3) ensuringthe partial environmentalpreservation of the Delta area. Thiscase history addresses geology and foundation problems, planning and construction sequence,site investigationand foundationpreparation, methods of construction,and foundation/structuralinteraction. The mainfocus is the megascalecontrol barrier completed in 1986across the 7.5 km-widemouth of the EasternScheldt estuary, the most difficultand by far the mostcostly section of the project.Here, andin otherparts of the Delta area,strong tidal currents and highly-variablegeological materials with relatively poorengineering properties were responsible for foundationsrequiring up to 80percent of the total constructiontime. The new techniquesdeveloped on the Project have world-wideapplication to futurecoastal and offshore construction. ADDITIONAL INDEX WORDS: Engineering geology, civil engineering, coastal engineering, open-water construction, delta-estuarine geology, foundations, storm-surge protection.

hydrodynamicregime encompassing fast-flow- INTRODUCTION ing tidal channels, changing estuarine con- figurations, nonhomogeneous subbottom The Netherlands Delta Project covers a sediments, a prolific, but delicately-balanced multi-riverdelta area created by the Rhine, ecosystem,and low-land areas subjectto peri- Meuse and Scheldt (Figure 1). Like most odic flooding (Figures 1 and 2). delta-estuarineenvironments, this area repre- Major storm-surgefloods occurredin 1953, sents, in its naturalstate, an extremelycomplex 1916,1912, 1906, 1894, 1825,1808, 1775 and 1717

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NORTHSEA

4N eZUID RZE S PROJ

DELTA PROJECT Rotterdom

Figure 2a. Satellite image showing the complex hydrodynamic Antwerp nature of the Delta area, and some major civil-engineering works either built, or under construction: (a) fresh-water Rhine discharge, (b) non-tidal, salt-stagnant water, (c) tidal km salt water (shades of grey indicate the intricate network of tidal channels), (d) Haringvliet Sluice-Gate Barrier, (e) AREASSUBJECT TO POTENTIAL'FLOODING Brouwers Embankment Barrier, (f) Eastern Scheldt Lift- Gate Barrier under Volkerak .. BORDER OF THE NETHERLANDS construction, (g) Waterway Dam and Navigation Locks, (h) Grevelingen Tidal-Control Barrier and the (i) Scheldt-Rhine Waterway Link under construction. (Satellite image by the National Aerospace Figure 1. The Netherlands, showing the delta area of the Laboratory). Rhine, Meuse and Scheldt rivers, and the locations of the Delta and Zuiderzee project areas where storm-surge structures have been erected to protect flood-prone areas (shown in stipple). (Modified after DOSBOUW v.o.f., 1983).

(Antonisse, 1986). Unlike many other deltas, Zeeland is densely populated and intensely utilized by man. In 1953 when storm-induced tides, some 4 m above normal, breached approximately 180 km of coastal-defense dikes and flooded 160,000 hectares of polderland, a huge loss of life and property resulted. The official death toll was reportedly 1,835. More than 46,000 farms and buildings were destroyed or damaged, and approximately 200,000 farm animals lost. However, a much larger area of the western Netherlands is sus- Figure 2b. The working model by Rijkswaterstaat at the to and had the Eastern Scheldt Delta-Expo provides a perspective on the ceptible flooding (Figure 1) mesh of natural hydrodynamic features and structural design storm penetrated the dikes of the Hollandse incorporated into the Delta works. The Dutch are world Ijssel (Figure 3) that protect this area, the leaders in hydraulic engineering. entire urban conglomeration of Rotterdam, the Hague and Amsterdam would have been polders more than 6 m below sea level (Figure inundated. It is important to note that approx- 4). imately sixty percent of the population of The Because of the low mean elevation and pre- Netherlands lives below mean sea level mium on space in The Netherlands, the Dutch (ENGEL, 1987) and that some areas contain have a long tradition of coastal-defense con-

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Figure3. Majorcomponents of the Delta Project:(A) BrouwersFixed Barrier, (B) HaringvlietSluice-Gate Barrier and NavigationLock, (C) VolkerakWaterway Dam and NavigationLocks, (D) HollandseIjssel Drop Barrier,(E) Zandkreek Dam,(F) VeerseFixed Barrier, (G) GrevelingenTidal-Control Dam, Lock, and Siphon Sluice, (H) EasternScheldt Lift-Gate Barrier,(I) PhilipsWaterway Dam and KrammerNavigation Locks and (J) OesterWaterway Closure Dam andNavigation Lock.Refer to Table 1 for a morecomplete description of thesecomponents. (Map after DOSBOUW v.o.f., 1983).

struction and land reclamation. This coastal subsidenceand risingsea levels. The people of conscientiousnessdates back fromfarm houses The Netherlandshave responded to the chal- built on artificalmounds around 400 BC, to ma- lenge of coastal protectionwith projects such jor dike worksbuilt in the eleventhand twelfth as the Zuiderzee Works (Figures 1 and 5), century(WALTHER, 1987). The need for con- enclosed in 1932 but still in the process of tinual coastal constructionhas intensifiedover having approximately150,000 ha of new land the years as a result of populationgrowth, land reclaimed and, more recently, the Delta Plan formalizedin 1958 by an act of the Dutch par- liament.The latter scheme became functional, in terms of storm-protection,in 1986 but con- siderable construction effort is still required on roads, bridges and other secondary structures to complete the project. The continued maintenance and improvement of dikes and waterwaysremain a life-long preoccupation. The core of the Delta Project called for the raising of existing dikes, the storm closure of all main tidal estuaries and inlets, but with provisionfor continuedinternational shipping access to Rotterdamand Antwerp,a non-tidal inland waterwaylink between these two ports and last but not least, an integratednetwork of Figure4. Approximately60 percentof thepopulation of The dams, salt/fresh-water separation locks and Netherlandslive in dike- and/or barrier-protectedareas belowmean sea level. flushing mechanismsto separate and manage the salt and fresh-waterenvironments in the Delta (Table1).

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Table 1. Summnaryof the major project componentsof the complete Delta Works,presenting the construction sequence, and the type and purpose of individual structures.

.f..t M..O. PRJECTC(...PONtNI. TC..ON...T..CTIOM PURPOSE

& Rhine 1 1958 HOLLANDSEUSSEL P OGuillotinesteel-pte dropbarrier OpenMode: Facilitates navigation DropBarrier Navigationlock discharge(?250 (?250 m /sec) Closed Mode: Storm-surge flood protection 2 1960 ZANDKREEK S Calmo-core& dredged-sandembankment Reducedtidal-current velocity for construction Tidal-ControlDam dam& of primaryVeerse barrier Providesnavigation to stagnantLake Veerse Navipgtion Lock 3 1961 VEERSE F Caisson-core& primarydredged-sand em- Storm-surgeestuary closure (with Zankreek FixedBarrier bankmentdam, with asphalt cover Damcreates Lake Veerse) S Combinationcableway block & caissoncore, Reducedtidal-current velocity for construction 4 1965 GREVELINGEN withdredged-sand dam; of Brouwersbarrier Tidal-ControlDam, Lock,& SiphonSluice Artificialisland for navigationlock & Facilitatesnavigation access to LakeGrevelin- gen Flushingsiphon sluice Siphonhelps flush Lake Grevelingen S Artificial-island& coffer-damconstruction on Reducedtidal-current velocity for construction 5 1970 VOLKERAK largelock complex (two locks for commercial of Haringvlietbarrier WaterwayDam & NavigationLocks traffic,one lockfor pleasurecraft) Contributesto Scheldt-Rhinenon-tidal waterwaylink P Artificial-island& coffer-damconstruction on ClosedMode: Storm-surge barrier 6 1971 HARINGVLIET piledpiers, for pivot-gatesluice barrier Sluice-GateBarrier & NavigationLock PartClosed & Open:Rhine discharge (fresh- Also cablewayblock-core embankment section watermanagement) Shippingaccess to NorthSea F SouthChannel: Cableway block core with Fixedstorm-surge estuary closure, sluice & 7 1972 BROUWERS dredged-sandembankment dam crestroad FixedBarrier Central:Dredge-improved sand bank NorthChannel: Caisson core & sandembankment S Coreof riprapand gravel placed by barge & Closureforms part of the Scheldt-Rhinewater- 8 1983 MAROUISATEQUAY truckdump waylink WaterwayClosure Dam Corepartially replaced by dredged-sand fill Reducedtidal velocity for OesterDam construction& Controlssalt-water intrusion to the east P Twodredge-improved artificial islands ClosedMode: Storm-surge flood protection 9 1986 EASTERNSCHELDT Lift-GateBarrier Threesections of pier-and-lift-gatesluice bar- OpenMode: Tidal flushing for preservation of rier salt-waterestuary Shippingaccess to NorthSea S Large-scaleartificial-island & coffer-damcon- Contributesto non-tidalconditions in the 10 1987 PHILIPSWaterway Dam & structionof KrammerLock Complex Scheldt-Rhinewaterway KRAMMERNavigation Locks Dredged-sandembankment closure KrammerLocks provide shipping access to EasternScheldt, but preservessalt-water east- ernScheldt & fresh-waterwaterway S Artificial-island& coffer-damconstruction of Partof Scheldt-Rhinecompartmentalization 11 1987 OESTERWaterway navigationlock closure ClosureDam & NavigationLock Dredged-sandembankment closure Facilitatesshipping access between waterway andthe EasternScheldt Controlssalt-water intrusion to the east

P = Primarystorm-surge control barrier, F = Primarystorm-surge fixed embankment dam; S = Secondarytidal-control and/or waterway embankment

Much has been writtenabout various aspects "Itis pointless to try to increase the accuracy of the Delta Project and the purpose of this of prediction (of foundation stability) by 10 case-historyreview is to summarizeimportant percent using advancedmethods while soil pa- features of engineering-geologic application, rameters may vary between 100 and 300 per- in particular,remedial worksthat were imple- cent." (NIEUWENHUIS, 1987a). mented to cope with potentialfoundation problems.The references cited address related aspects Overview of investigation,design and construction in greater Both the nature of the and the technicaldetail than the presenttext. project geology of the area precluded the usual option of relocating structures to sites of significantly GEOLOGYAND FOUNDATION PROBLEMS better foundation conditions. In the western

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materialsof the Eastern Scheldt estuarypro- vides an example of the rapidly changingsoils conditionsthat are typical of the Delta region (DE MULDERand VAN RUMMELEN, 1978). Nonhomogeneoussubsurface conditions pose potentialfoundation problems such as differential settlement.More specifically,peats are susceptible to creep consolidationand must often be entirelydemucked. Soft clays and loose sands exhibitpoor bearing capacity, while the latterare subject also to scour erosion, piping beneath barriers,and wave and/orocean swell-induced liquefaction(BJERRUM, 1973;DE LEEUW, 1976). At first sight, such soil conditionsmight justifiablyhave been consideredentirely unsuit- able for the size and complexityof proposed projectconstruction works and the heavyfoun- dationloads that these wouldimpose. However, conventionaland new techniqueswere adapted to cope withthese problems and are discussedin the "FoundationPreparation" subsection of the EasternScheldt. It is of considerableinterest to note that as a broad-based guideline to foundation design, moneywas consideredto be spent more cost-ef- fectivelyon the accuratedelineation of the engineering-geologiccharacteristics of subsurface materialsthan on the use of sophisticatednumeri- cal foundation-predictionmethods. The first- principlesapproach to foundationdesign is best summarizedin the furtherwords of NIEUWEN- HUIS (1987a),the Chief GeotechnicalProject Engineer: "...Wewould therefore conclude that a know- ledge of basic soil mechanics,combined with experienceand sound engineeringjudgement, should enable a constructionwork such as the closure of an estuaryto be properlyand eco- nomicallydesigned and constructed."

Figure 5. Air-photograph oblique of the Zuiderzee closure EngineeringGeology works. (Photograph courtesy of Bart Hofmeester, Aerocamera. Rijkswaterstaat,Meetkundige Dienst Afdeling In very simple terms, the engineeringgeol- Reprografie). ogyof theProject area may be dividedinto two broadunits: Netherlands hard rock can be found only at (1) An uppersequence consisting of inter- depths of one kilometer and more (ENGEL, beddedlayers of clay,clayey-sand, sand and peat 1980).This is, therefore,a soils (i.e. unlithified exhibiting relatively poor engineering char- sediments) project area exhibitinghighly-vari- acteristics. This sequence was deposited during a able and consistently-poorengineering-geologic marine transgressionin the Holocene period (the conditions.Figure 6, a geologic cross section last approximately10,000 years), in response to a through part of the subsurface-foundation warming trend, the melting of ice sheets and a

Journal of Coastal Research, Vol. 6, No. 3, 1990

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1 (D) (D) (B) (B) (DI) B) DIKE-PROTECTED ( D), - ARTIFICIAL .., LIFT GATE BARRIER ,.. ISLAND (DI) S N 7-7 4,A"7 A ' A'' 7-.. 1*, . I t 0 ? 4.tWA- -

." .: - .. 1":1 , ~ ...1.... j.jt_~^li.;l.llcl?ll.lll .•, __~~...... )T

IL'h ______

CS mc/ 00 s , .e T..,e-Forrcl.. e r--... s_ IIiII JIfff{ Ilp I Tr lT1J l

wres!!cr d F3 1.)1ct n: c c Pe 0 Eee Fo-'r ci'o ncster cu!' Fc rn ior',

c _ ege o c!o Bredc3 Fo-nction fc'mctjorso.ndc- te'•tct ve 1 eposits - • ... .ee .e. t.o E]] Forrr tolof . .... Pqup e? Figure 6. Geologic cross section through the Eastern Scheldt barrier alignment, showing changing soil conditions typical of the general Delta area. (B) lift-gate barrier, (D) dike-protected land, (DI) dike-protected artificial island. (Cross section modified after De Mulder and van Rummelen, 1978). consequent global rise in sea levels following consolidationload of sedimentsthat have been the most-recent "ice age." As shown in Figure subsequentlystripped awayby erosion. 6 (see base of Holocene Westland Formation The sedimentwedge of engineering-geologic deposits) this unit reaches a depth of up to 30 interest does not extend much below -100 m m beneath the seabed; however,it is consider- (MSL) and is characterizedby rapidlyfluctuat- ably thinnerin tidal channelswhere the upper, ing sea levels in responseto glacialand intergla- predominantlysandy layers have been removed cial periods.The resultwas the complex mix of by scour erosion. marine, littoral and terrestrial(including peri- (2) A lower sequence of interbedded clays glacial) sedimentsshown in Figures6 and 7. and sands with somewhat better engineering In reviewing the geologic section, it may be characteristics (than the overlying Holocene noted that some deposits, like the Eem Forma- sediments described). This lower unit consists tion shown, were at one time far more exten- of both marineand terrestrialmaterials depos- sive, but have been removed in large part by ited duringa periodof changingsea levels,above erosion (DE MULDER and VAN RUM- and below present sea level, dating from Mid- MELEN, 1978). This occurred particulary dle-Oligocene time (Figure 7). The better en- during the onset of respective glacial periods gineering characteristics of these older soils when sea levels began falling and previously- may be attributedin part to the consolidation inundated land was exposed above sea level. produced by the weight of presently-existing For example, during the Weichselian, the Holocene sediments, and in part by the over- most-recent glacial period (approximatley

Journal of Coastal Research, Vol. 6, No. 3, 1990

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ApproximateEustatic Sea LevelsRelative Epochs Scale to Present-DaySea Level Formation GeologicHistory Ma Above Below 0- +200 +100 Meters -100 -200 Pleistocene Depositionof Pliocene -" 5 Formations MarineLittoral -5 (See Text) andTerrestrial Sediments

Late - Deposition of -10 OosterHout Marineand M - Terrestrial I - (Coastal) Sands O Middle - C iDeposition of E-15 Breda Glauconiferous N Marine Sands - E 20 Early 2 ExtensiveErosion (Formations in Responseto Removed) TectonicUplift and a Relative of O0- -25 SeaLevelDrop L Late " I

O - Depositionof C - I MarineClays E - Rupel (Note: Top of N Early Formation95-135 m E 35 below MSL)

Figure7. The post-Eocenegeologic history of the projectarea is largelya functionof fluctuatingsea levels.

70,000 to 10,000years before present) the en- tificial islands in the Eastern Scheldt Estuary tire "delta"area was exposed well above sea was to significantlyincrease flow and scour in level. the tidal inlets that remainedopen. This added With the warmingtrend at the beginningof considerably to the problems of foundation the Holocene, rising sea levels initiated, as design for the barriers that subsequentlyhad mentioned,the marinetransgression which re- to be constructedin these tidal inlets. sulted in the deposition of clays and peats of the near-surfaceWestland Formation. Finally, Foundations reactivated transgression,starting about 500 Besides a of yearsBC, was responsiblefor the depositionof being function the engineering- characteristics the Dunkirk sands, the uppermostdeposits of geologic of the site, the techni- the WestlandFormation (DE MULDER and cal aspects of foundation design are dictated in VAN RUMMELEN,1978). These authorsnote major part also by (1) the purpose of the furtherthat it was as recentlyas 700 AD that the project and (2) the nature and size of civil-en- structuresthat best serve Western Scheldt estuary began to form and gineering this project capture the principaldischarge of the Scheldt purpose. As shown River.In the past few years,geologic processes in Figure8, barriersexposed to the NorthSea had to have their have accelerated again, this time in response both structuraland to the works of man. For example, nature's foundationcomponents designed to withstand compensation for the upset in the hydraulic storm-surgeand wave loadingresulting from a equibriuminitiated by the constructionof ar- combinationof probablemaximum storm condi-

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ASTRONOMICAL PROBABLE-MAXIMUM TIDE WINDFIELD

WIND I)EE P-WATER WAVE SET UP GENERATION

STORM-SURGELEVEL SHOALINGCOASTAL LOCAL WINDFIELD & WAVE

S OCEAN/BASIN STORM-SURGE WAVE GROUND-WATER SEEPAGE LOADING LOADING LOADING -'

BARRIER (FOUNDATION/STRUCTURAL) DESIGN

DELTA-ESTUARINE AREAS EXPOSED TO THE NORTH SEA

Figure8. Simplifieddiagram showing the impactson designof worst-casestorm and tidalloading. tions and maximumspring-tides. place of the more-conventional foundation A numberof closure, constructionand foun- caisson used, for example,on the Thames Bar- dation options were availableto engineers,and rier in England (Figures 11 and 12). some of those that were successfullyused are As far as foundation designper se, the main shown in Figure 9. In general, rigid (concrete considerations are summarizedin Figure 13. and steel) structuresare more expensive than As shown, the foundationsof both flexible and flexible (largely geologic-material)structures, rigid structures must be designed in terms of so that use of rigid componentswas generally (1) stabilityagainst bearing-capacity failure and restrictedto lift or sluice-gatestructures, naviga- (2) deformationagainst excess, or differential tion locks and the caisson-coreunits for flexible settlement. embankmentdams. Figure 13 also lists the main design stresses Foundation/structuraloptions in themselves that must be considered. As shown, open- presentedcertain advantages and disadvantages water construction requires special emphasis and these are briefly summarizedin Figure 10. on dynamic forces. Discussion of these is be- The authorssuggest that the combinationof sta- yond the scope of the present text, but the bilized soil, mattress and prefabricatedpiers, following references maybe consulted for fur- designed for the closure of the EasternScheldt ther detail: estuary,may be more widely used on the long (1) current-induced scour (PILARCZYK, closures of other projects in the future, in 1987b),

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CLOSUREOPTIONS

RIGID SIRUCIURE IFLZEXIBLESIRUCI1URE e.g. Caisson or Monolithic Pier e.g. Sand Embankment (May require rigid-component core)

CONSTRUCTION OPTIONS

PREFABRICATED ON-SITE DREDGED-SAND CABLEWAY D COMPONENIiS (COFF1RDAM) EMBANKMENT C LOCP OR CONSIRUCnION (rigid caisson core) RUBBLE

FOUNDATION OPTIONS

STABILIZEDSOIL PILES EROSIONMATTRESS PILE-SUPPORTED

Protectedby: Protectedby rockrubble Protectionfor core cais- Cablewaypiers; possible sons mat of Erosionmats Non-piledfoundation protection seabed Gradedfilter protectedbyernosion mats (e.g. VeerseDam) (e.g. Southcction of BrouwersDam) Rock sill (e.g. Hlaringelietdis- charge sluices) (e.g.Eastern Scheidt)

Figure9. Someclosure, construction and foundationoptions available to Delta-Projectdesign engineers.

(2) seepage-induceduplift pressuresand pi- (where practical)that was predicatedby least- ping (PILARCZYK,1987a; v.d. BURG and to-most-complicateddesign requirements.This NIEUWENHUIS,1987), simple philosophyenabled relatively rapid pro- (3) wave and/orearthquake induced liquefac- gressto be madeat the outsetof the project,and tion (AMBRAYSEYSAND SARMA,1967; DE establisheda learningprocess that proved in- LEEUW, 1976; NIEUWENHUIS, 1987B; valuablein the latterstages of construction. SEED, 1979; VAN AALST and BRUINSMA, The sequence, type and purposeof construc- 1987)and tion of major components of the scheme are (4) ice-jam loading (PILARCZYK,1987a). presented in Table 1. This highlightsa major General discussion,including design against technical factor influencing the construction static-loading conditions, may be found in sequence, namelythe need to reduce tidal-cur- BJERRUM,1973; BRUUN and JOHANNES- rent velocities in the four main estuaries be- SON, 1976;BRUUN and KJELSTRUP,1981; fore the constructionof primarybarriers could SMITS,et al., 1978. be undertaken.Tidal velocities were lowered by constructingsecondary compartmentalization barriers (e.g. ZandkreekDam, Grevelin- PLANNINGAND CONSTRUCTION gen Dam, and VolkerakDam - Figure 3) to reduce the extent of the Delta area to SEQUENCE subject tidal influence (RIJKSWATERSTAAT,1987). This in in a reduced tidal vol- An the resulted, turn, importantingredient in planningof the ume lower current velocities was to follow a construction and, therefore, project sequence throughthe main estuaries.

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...... *...... * ..:. ..: : : : : : ..: ..:::::::::::::::::::::.:::::::::::::::.:.. ..:...... :::::::::: :. ..::::::::::::::::::: ..::A::::::::::::

NORTH SW SEA NETHERLANDS MINIMALFOUNDA- LONGPERIOD OF PILESSUPPORTING TION OPEN-WATERAND/OR CAISSONSOR PIERS PREPARATION COFFERDAM CONSTRUCTION LARGEFACTOR OF SAFETY

FACILITATES REQUIRESSTRINGENT STABILIZEDSOIL MAXIMUMUSE OF PRE QUALITYCONTROL (PROTECTED) FABRICATEDCOM- ON: SUPPORTINGCAISSONS PONENTS SoilStabilization (e.g. OR compaction & density) MONOLITHIC PIERS MINIMIZES DEEP- WATER CONSTRUC- FOUNDATION TIONTIME PREPARATION (e.g.levelling)

FOUNDATION MINIMALFOUNDA- TIMECONSUMING & CAISSONS [TION LABOR-INTENSIVE SUPPORTINGPIERS OR PREPARATION UNDERDIFFICULT & CAISSONS FATRF POTENTIALLY . . LAR.GE FACTOROF DANGEROUSON-SITE SAFETY CONDITIONS

Figure10. Advantages and disadvantagesof some foundation/structuraloptions.

It may be noted further, that secondary com- in the Eastern Scheldt is typical (Figure 16). partmentalization works also served the dual This figure shows approximately 80 percent of purpose of (1) impounding the Rhine/Scheldt construction time (not including site investiga- water way and (2) creating a fresh-water buff- tion) spent on compaction and other soil-im- er zone to inhibit salt-water intrusion from the provement procedures, building of the foundation Delta region to the agricultural areas east of bed, and completion of the rock-rubble sill to Bergen Op Zoom (Figure 3). protect the foundations of the gate-piers (VAN All of this construction, in turn, imposed a DER SCHAAF and OFFRINGA, 1980). new environmental regime on the Delta, that relies for its preservation on the design of a complex support system of flushing structures. METHODS OF CONSTRUCTION A good example is provided by Lake Grevelin- gen, where a desirable salt content is main- Rather than discuss in detail each of the tained sea water an inlet pro- by circulating though ject components summarized in Table 1, the con- sluice in Brouwers Dam (Figure 14), and dis- struction-methods used for these various charging excess water from the Lake to the structures are outlined under three Eastern Scheldt with a sluice built into subheadings: siphon embankment dams, artificial is- Dam (1) primary (2) Grevelingen (Figure 15). lands and cofferdams, and struc- With to the construction se- (3) secondary respect planning tures dams). A for individual it is (gravel-and-sand-embankment quence structures, important fourth method employing prefabricated mono- to remember that the of preparation complex lithic piers on a stabilized foundation is discussed foundation sections consumed a high proportion in the section on the Eastern Scheldt. of the total construction time. The schedule shown for completion of the Roompot channel

Journal of Coastal Research, Vol. 6, No. 3, 1990

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A__ac eL to

d I; isingSector C

Figure12. The ThamesBarrier, large as it is, is dwarfedby the closure of the EasternScheldt estuary,let alone the smallvessel C-co t concrete combinedworks of the Delta Project(the ap- co cr.te Pie, cast ,o Ii119 S,, Set or Rubber, the barrierfrom a downstreamdirection 5rr Deep proaching provides 4 Sheetrpied Pa, in Ricer Bed an ideaof scale). Foundation-p a vehiclecapable of droppingcast concrete blocks (Figure18). These blocks accumulate in a line on the seabed and eventuallyrise above sea level. The method has advantageover rubble place- Figure11. The Thames Barrier Design. The authors note that ment by barge and other dumpingvessels be- thecombination of stabilizedsoil, mattress and prefabricated cause when near completion, barges can float piers, designedfor the foundationsof the EasternScheldt over the dam at tide estuary,may be more widelyused on the long closuresof retaining only high (HUIS otherprojects in the futurein placeof the more-conventional IN 'T VELD, 1987a).A cableway,on the other foundationcaisson(s) used, for example,on the Thames hand, be operated independentlyof tidal Barrierin England. may cycles and in most weather conditions. The advantageof a cableway system over caisson PRIMARYEMBANKMENT DAMS constructionlies in the fact that slow loading and overall bulk minimize the need for foun- Large embankmentdams are used for the dation preparation.This phenomenonis char- total closure of estuaries (e.g. Veerse Dam, as acteristic of all rubble-mound structures depicted in Figure17). As shown,construction (WATSONet al., 1963)and is an economicalcon- consists of an inner core of ballasted caissons, structiontechnique because problems associated or concrete blocks, covered by a bulk shell of withexcess settlement tend to be builtout during dredged sand. construction. The inner core of the damis the most critical The technique was first used on the Greve- component.It is also the most difficultto com- lingen Dam (1963) and subsequentlyin a final plete, because constructionmust contend with section of the HaringvlietDam (1970); it was the full force of tidal currents. Without the also deployed again in 1971 for the large core in place, attempts to close the estuary southern section of Brouwers Dam (VAN with dredged fill would be futile because sand WESTERN,1987). would be constantly washed away. The two main techniques used for core construction CaissonSudden Closure are discussed in what follows. This alternativemethod of core construction to and BlockGradual Closure (as opposed gradualclosure) employs pre- Cableway fabricatedbox caissonswith a built-in steel lift This methodemploys a pile-supportedcable- gate formingone (long) side of the caisson,and way on a continuousloop. The cablewaycarries temporarytimber panels forming the otherside.

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FOUNDATION-DESIGN CONSIDERATIONS

I I STABILITY DEFORMATION

FLEXIBLE FLEXIBLE

RIGID .RIGID . .

...... iiii iiiiii ...... i iii -ii•...... I...... ,.o I , .. , DESIGN STRESSES ii, ,. I

STATICLOAD DY N A ...... I..... IC...... "..."".".." :::::~~i~Sij'...... J ~ ""... WATER•...... v LOADDISTRIBUT ON PRESSURE

VELOCITYPROFILE .... CURRENT-INDUCEDSCOURR HOLE --

SEEPAGE-INDUCED - UPLIFTPIPINGPRESSURE D-: NI .. .

SEA BASIN WAVE and/or EARTHOUAKE-INDUCED titii~iiiit~~iiiitr~~iLIQUEFACTION --,

ICE-JAM LOADING

Figure13. Summaryof some foundation-designconsiderations that mustbe takeninto accountto offset a combinationof staticand dynamicstresses.

With the gate closed and the sliding wooden to facilitate free tidal flow throughthe caisson. hatches in place, the caisson may be floated to In a similar way, additional caissons are ma- the construction site and positioned, at slack neuveredinto place by tugs and tied together. tide, along the proposed barrier center line. When the last caisson has been positioned in Sea-watervalves are then opened and the cais- the channel (Figure 17) and secured, lift gates son sunk in place. The timber sections are are dropped simultaneouslyto complete the removed quickly, and the caisson gate raised closure.Caissons are thenballasted with dredged

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Figure15b. The Grevelingen-Damsluice under construction. (AfterRijkswaterstaat, 1987).

Figure14. The sluicein Brouwersfixed barrier circulates sea tion materialsfor caissons, are susceptible to water to the impoundedestuary; hydraulic flushing is an scour erosion by tidal currents.Because tidal importantaspect of helpingto preservethe environmental qualityof the Delta. (AfterRijkswaterstaat, 1987). erosion might cause caissons to tilt or other- wise fail, foundations are protected by prefabricated"mattresses," a graded sill of gravel and rock rubble, a combination of both, or LAKEGREVELINGEN KRAMMER some other form of bottom protection (VAN HUIS IN'T VELD; VALVEOPEN WESTERN,1987; 1987b). (a) For centuries the Dutch have constructed ,/ scour-protectionmattresses of brushwoodand reed, ballastedwith rock. More recently,however, the performance of bottom-protection FLOW ACTIVATED works has been improved by using synthetic BY VACUUM PUMP VALVE CLOSED fabrics and other man-made materials and design-gradedfilters (Figure 19). This modern (b) techniqueis discussedfurther in the subsection tAh on "FoundationPreparation" for the Eastern : ...... Scheldt.

ArtificialIslands and CofferDams (c) The Dutch are the dredge masters of the world and wherever on the project ...... practical they took advantageof high-lyingsand banks these into the barrier Figure15a. A cost-effectivesiphon sluice is partof the flush- by incorporating design. ingsystem for LakeGrevelingen. (a) In an open-valvemode Such dredge-improvedislands formed impor- atmosphericpressure prevents flow through the siphon.(b) tant componentsof the two main-estuarybar- In a closed-valvemode a vacuumpump may be usedto lower atmosphericpressure and activateflow through the siphon. riers, BrouwersDam and the Eastern Scheldt (c) Shouldit be decidedto makeLake Grevelingen a fresh- (Figure 20). waterlake, the sluicemay be extendedthrough Philips Dam Extensiveuse also was made of the and flow through siphon reversed. (Modified after dredged Rijkswaterstaat,1987). artifical-islandand cofferdamconcept, for the construction of all major in-situ concrete sand. Finally,a dredged sand embankmentis works on the project. For example, Figure 21 placed over the caisson core and appropriately shows the dredged cofferdamconstructed for reinforcedagainst wave erosion. the concrete gate-supportpiers of the Haring- It should be noted that the predominantly vliet barrierdischarge sluices, which were built sand channel beds that constitute the founda- in place; sluice-gatepiers on piled foundations

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z o ROOMPOT

o on

o-4 .

o 8P

Figure 17. Veerse primary-embankment barrier showing: (a) tugs positioning the last caisson for the "sudden closure" core of the dam. (b) The approach embankment with a crest road; SUMPROVEMENT this will eventually extend over the caisson core. (Photog- raphy by Bart Hofmeester, Aerocamera. Rijkswaterstaat, Meetkundige Dienst Afdeling Reprografie).

A o• were conveniently constructed in the dry. On completion, the cofferdam was flooded, removed and the sluice gates incorporated in the barrier dam. 22 shows a further of the use ...... o Figure example O.IL o of a dredged artificial island, for the cofferdam 0p DA71' construction of the Krammer locks in the Philips Jv?? Dam. oo A . A IE 00l;00c .*.... Secondary Structures 0:;::O:: 0 A great number of secondary embankment .....0;:: ... dams and transitional structures were built to ...... 0 serve as approaches for primarybarrier closures, ...... 0 0 :?: as connectors between barriers and 44 :: dikes, or as compartmentalization structures for waterways.

CA) 0 ...... C' .... These consist of rein- .. . 0 0 essentially dredge sand, ... -,.* .,-*.. forced against erosion by one or a combination of asphalt, concrete, paved stone, or rip rap (SCHELLEKENS et al., 1980). In the case of the Marquisate Quay, closed in the spring of 1983 (Figure 23) to serve as a section of the Scheldt-Rhine waterway (Figure 2), initial stone rip-rap construction was completed by a combination of stone-dump barges, rubber-tired tip trucks and hydraulic scoop cranes. Once the core was raised above lilill ill lilt, Ill 111111A rip-rap BP = water level, sand was in such a APR APRON dredged placed - way that a large volume of the (short-supply) rip Figure16. Constructionsequence for the Roompotchannel, rap could be removed for other Eastern Scheldt;note that about 80 percent of the total conveniently constructiontime was spent on foundationpreparation. sections of the project (RIJKSWATERSTAAT; (Aftervan der Schaafand Offringa, 1980). 1987).

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Figure19. A graded-filterfoundation mattress constructed of both naturaland syntheticmaterials offers protection against:(1) scourand currents, (2) piping(seepage erosion) inducedby the differentialhead of waterwhen barrier gates are closed, (3) excesspore waterpressures caused by pier- placementloading and (4) liquefactiondue to stormwaves.

Figure18. Cableway vehicle used to dropconcrete blocks for the "gradual-closure"method of core constructionfor em- bankmentbarriers. (Rijkswaterstaat, Meetkundige Dienst AfdelingReprografie).

Figure20a. The Dutch are the dredgemasters of the world andfrequently, as herein the EasternScheldt estuary, made use of artificialislands to facilitatecost-effective construc- EASTERNSCHELDT tion. This photograph(looking south) shows two dredged islands:(a) Roggenplaatand (b) NeeltjeJans, originally used as a constructionbase, and presently home of theDelta-Expo Overview museum.See Figure20b for furtherdetails. (Photography by Bart Hoffmeester,Aerocamera. Rijkswaterstaat Meetkun- DienstAfdeling Reprografie). The originalmaster plan for the closingof the dige Eastern Scheldt estuarycalled for a complete of two closure,a primaryembankment dam. However, wouldremain after the completion large to preservethe naturalsalt-water environment of artificialislands, see Figure 20). com- the estuary,the design was The new design, althoughvastly more subsequently changed and consider- to a sluice-gate barrier (ENGEL, 1980; DE plex froma technicalstandpoint, thecontinued tidal JONG et al., 1987). The revisedplan called for ablymore expensive, facilitated and a control barrier consisting of some 65 pre- flushingof theestuary, was,therefore, justified fabricated concrete to on environmentalgrounds. Some examples of food piers support sliding whichwould have been steel gates in the three tidal channels (which chainsin an estuarineweb destroyedas the waterbehind a fixed dam gra-

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SEE GEOLOGIC N CROSS SECTION N

. N SCHONUWE

HAMMEN

Construction- 300 island access .. bridge

ROGGENPLAAT

200 NORTHSEA SCHAAR -.. NEELTJEJANS'"

Cofferdam(s) for pier DAMVAKGEUL • construction •-• .-5 NOORDLAND EASTERN SCHELDT

------BASIN

-20 ROOMPOT k 300 0 2km - -10 -- ' Depthin m. MSL Precompletiondischarge (m3/s) 200o--w St?NO~flO EVELAN

Figure 20b. Plan of the Eastern Scheldt estuary showing the two dredge-improved sandbank islands and three tidal channels controlled by the lift-gate barriers. dually became fresh are shown in Figure 24. Artificial Islands and Construction The Eastern Scheldt barrier, as redesigned, Cofferdams remains normal open during circumstances, Further to the first but be closed for routine and previous discussion, phase may testing, per- of the Eastern Scheldt scheme consisted of an once a when is haps year storm-surge flooding extensive to convert two na- as a of north-west dredging operation predicted result, especially, tural sand banks in the into storms AALST and estuary permanent (VAN BRUINSMA, 1987). artificial islands. The of these was de- A facilitates access to larger locking system shipping to serve as a convenient construction the North Sea. signed complex (Figure 20). Four cofferdam compart-

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Figure 21a. Haringvlietcofferdam and dewateringsystem Figure21c. Haringvliet sluice-gate barrier in operation.Note enabledpiled foundations and sluice-gate support piers to be gate "a"open to facilitateRhine discharge; gate "b"closed. constructedin the dry.(Rijkswaterstaat Meetkundige Dienst AfdelingReprografie). engineering-geologicaspects of the Eastern Scheldt project related to the preparationof foundation materials to support the barrier piers. In pier-and-gatedesign, foundationin- tegrityis criticalto ensurejam-free gate operation. Hence, the toleranceson initiallevelling, on dif- ferentialsettlement, and on tilt resultingfrom foundation failure, are extremely stringent (NIEUWENHUIS, 1987; BOEHMER, 1978; BJERRUM,1973). As with previousbarriers, foundation problems were compounded,on one hand, by the loose and/orsoft and extremelyvariable nature of typicalestuarine subbottom sediments (Figure 6), andon the otherhand, by the scourpotential of sea-bedsands in responseto strongtidal cur- Figure21b. Followingcompletion of the Haringvlietsluice- rents (PILARCZYK,1987). gate barrier,the cofferdamwas flooded and subsequently to the full benefit of dismantled.(Rijkswaterstaat Meetkundige Dienst Afdeling Furthermore, reap rapid Reprografie). prefabricatedpier construction,piled foundations such as those used on the Haringvliet sluice gates, could not be used. ments were built within the island, to match a Engineeringgeologists and civil engineers, four-phase constructionsequence for barrier therefore, designed an extensive program of piers.The ring-dikecofferdams were excavated foundation investigationsand preparation,to to approximately15 m below sea level,to provide be implementedin a series of steps. These are sufficientdraft for the subsequenttransport of summarizedin the discussionthat follows. piers. As soon as all of the piers in one section were completed,the compartmentwas flooded Site Investigation and Foundation and a speciallydesigned lifting vessel (Figure 25) Preparation was used to move the piers to the barriercenter line. Investigation Phase 1 Conventional geophysical, drilling and sam- FoundationRequirements pling surveys and in-situ tests were conducted in an effort to delineate the 3-dimensionaldis- As emphasized,one of the most demanding tribution of subbottomsediments. Combined

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Figure 23b. A dredged-sand embankment over the rubble core completes the dike and eliminates a tidal influence on this section of the waterway. The Kreekrak lock system is in

Figure22. A furtherexample of mega-scalecofferdam use for the constructionof the pump house, supportculverts and Krammernavigation lock systemin the Philipsdam. (After Rijkswaterstaat,1987).

Figure 23c. The 120 kilometer protected waterway between Rotterdam and Antwerp has created one of the busiest and most economical links in Europe for the transport of commercial cargo: this picture shows barges emerging from the Kreekrak locks. (After Rijkswaterstaat, 1987).

Figure 23a. A critical section of Marquisate Quay under construction on the Scheldt-Rhine waterway link. Note the strong tidal flow through placed-fill core materials in the closure dike. (After Rijkswaterstaat, 1987).

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Figure24. Some components of the estuarinefood chain that would have been disrupted under the originalmaster plan which calledfor completeclosure of the EasternScheldt. (After de Jonget al., 1987).

Vibrocompaction Large-scalevibratory compaction equipment was used to improve the bearing capacity of granularmaterials in the proposed vicinity of piers (VAN DER SCHAAF and OFFRINGA, 1980). Compactionwas accomplished over a period of three years using a special compact- ing rig,Mytilus (Figure 26). The method, pion- eered by the Dutch with smaller-scale equipment,is used to compact granularsoils. The techniquerelies on the vibrationof probes introducedinto the ground, to rearrangethe Figure25. A speciallydesigned vessel, Ostrea,transports a packingof discreteparticles of soil into a denser gate-supprt pier fromthe floodedcofferdam construction and hence its mass yardon Neeltje Jans, to the EasternScheldt barrier align- configuration, improve per ment. (Photograph by Bart Hoffmeester, Aerocamera. unitvolume in the vicinityof the probe.As shown RijkswaterstaatMeetkundige Dienst Afdeling Reprografie). in Figure26, Mytilusemployed the simultaneous use of fourvibrating probes, and at each set-up with laboratory-testingsupport, these surveys location was capable of compactingsoils to a and tests assisted in the assessmentof the en- depth of approximatley15 m, over an area of gineering-geologiccharacteristics of each de- about 6 X 25 m2 fined layer (VERMEIDEN AND LUBKING, 1978; WATSON and KRUPA, 1984; NIEU- InvestigationPhase 2 WENHUIS, 1987b). A second phase of geotechnical investiga- tions assessed the results of compaction.This Demucking programemployed a surveybarge the Johan V, Soft, compressibleclays and peats were exca- equiped with a conventional drilling rig for vated and replaced with sand. obtainingboth "undisturbed"samples for la- and in-situtests on Coarse boratorytesting performing Levelling site. An example of the latter is the dynamic Depressions in the tidal channelswere filled StandardPenetration Test (SPT) used to deter- with sand to a design elevation, and covered mine the relativedensity of granularsoils, and with a layerof protectivegravel to inhibitscour the consistencyof cohesivesoils (WATSONand erosion. KRUPA, 1984). In addition, Johan V was

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and asphalt slabs formed the outer periphery of the seabed protection apron, while the more expensive graded-filter mattresses, subsequently discussed, were used under the gate- support piers. Foundation Mattresses Graded-filter foundation mattresses, each 36 cm in thickness, consisted of natural sands and gravels grading coarser in an upward direction; sand and gravel is held and separated by synthetic fabric and flexible stainless steel mesh, pins and cable (Figure 19). The function of these mattresses, as discussed, was to prevent the erosion of foundation sands, but filter mats were designed also to meet a number of additional needs related to foundation integrity (PILARCZYK, 1987; Figure26. The Dutch are the pioneers of thevibrocompac- V.D. BURG and NIEUWENHUIS,1987; and tionmethod used over a periodof threeyears to improvethe VAN DER SCHAAF and OFFRINGA, foundationcharacteristics of subbottom granular soils in the 1980). EasternScheldt estuary. Schematic diagram shows the spe- For example, filter mattresses helped to dis- cially-designedcraft Mytilus, which employed the simul- created to achieve sipate porewater pressures by pier- taneoususe of fourlarge-scale vibratory probes and thus ensured that compaction.(After DOSBOUW v.o.f., 1983). placement loading, settlement was rapidly built out prior to the installation of gates. Furthermore, during storm- equipped with a diving bell which enabled in- surge operation, filter mattresses will inhibit situ seabed density measurements to be under- potential piping erosion due to the differential taken (VAN DER SCHAAF and OFFRINGA, head of water across the barrier (when closed). 1980). Finally, graded filters were designed to prevent potential liquefaction of foundation soils by Anchor Piles storm waves. During construction a large number of ves- Foundation mattresses were placed by a spe- sels were required to work along the barrier cially-constructed barge Cardium (Figure 28). alignment. Therefore, to prevent anchor dam- This vessel is fitted with a levelling dredge and age to the prepared seabed, and to the erosion- compactor for final preparation of the seabed, protection mats that would subsequently be before mattress placement. Each mattress is placed, underwater mooring piles were driven unrolled at slack tide from a large reel into the seabed. These were fitted with heavy mounted on the after end of the barge. The mooring cables (attached to a marker buoy) lower mattress was laid in sections measuring which could be hauled aboard to secure a ves- 200 X 42 m2. A second smaller mattress meas- sel for a particular task, and then cast off to uring 60 X 29 m2 and again 36 cm thick was rest on the seabed until needed again. then placed at the proposed location of each To ensure level of the Erosion Mats gate pier. placement pier base, fine-leveling adjustment was achieved with To protect the prepared seabed from severe a third (block) mattress (Figure 29). Finally, a erosion by tidal currents, a combination of poly- fourth, heavy stone-ballast mattress was laid down propylene and concrete-block mats, asphalt in sections of 200 X 13.5 m2, to protect the filter- slabs and graded-filter mattresses were used. mattress joints. The foundation bed, prepared in This protection followed the proposed barrier this way along the entire center-line lengths of the alignment and extended for approximately 500 lift-gate barrier sections, was now ready to recieve m on either side of the center line. As shown in piers. Figure 27, the concrete-weighted erosion mat

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Figure27. Concrete-weightederosion mats form the outer ripheryof the seabed-protectionapron of the Eastern 28. As of the foundationfor the Eastern Scheldtbarrier (illustrated in Figure29); an 18-cmgeological Figure part Scheldt notebookshows scale. barrier,a specially-designedbarge was used to laydown filter mattresseson the preparedseabed (from reel on the aft-end of the barge).Drawing shows: (1) foundationmattress being unrolled,(2) weightedbeam which holds the end of the mattressin place,(3) smallsurface compactor and (4) a small Pier Placement levelingdust-pan dredge. (Photograph by BartHofmeester, Aerocamera.Rijkswaterstaat, Meetkundige Dienst Afdeling As mentioned,a special pier transporter,the Reprografie). Ostreawas designedto move one prefabricated pier at a time from the flooded coffer dams, to in the barrier configurationover a period of the barrieralignment (Figure 25). The design two years. of the Barrier called for 65 piers with base Like the foundationmattresses, the sill was dimensions of 25 X 50 m2 and a maximum of graded design, with four layers of rip rap height of 43 m (VAN DER SCHAAF and OF- quarrystone, increasing in size in an upward FRINGA, 1980). Positioningwas achieved by directionabove a filling-inlayer of 5-40 kg slag securingthe Ostreato a mooringpontoon, the and stone on the upper foundationmattresses. Macoma. Macoma was fitted with a broom- Above this sill, layersconsisted of stone rubble type suction dredge capable of removingany in the weight ranges of: (1) 10-60 kg, (2) 300- sand which might have collected on the upper 1000 kg, (3) 1-3 tons and (4) a shell of 6-10 ton foundationmattress (DOSBOUW, 1983). armorstone, protectingthe outer seawardside of the barrier (VAN DER SCHAAF and OF- Rip-Rap Sill FRINGA, 1980). To provide for the long-term stability of in- Smaller quarry-runstone was dumped, but stalled piers, and the adjacentfoundation area to avoid damageto piers, larger rip rap had to surroundingpiers, an extensive sill of graded be placed with special vessels (Figure 32). rip rap was placed so that, on completion, Placementof the armorstone completed the piers were embedded within several layers of foundation. rock (Figure 30). The sill requiredsome five million tons of rock Superstructure rubble from in Fin- supplied quarries Belgium, Sill Beams:As shownin the lowest land, Germanyand Sweden. The selection of Figure30, suitable rock and the of such a componentsof the superstructureconsist of pre- design large stressedconcrete sill beams.These beams rest- structurerepresents a significantengineering- in itself and ing on and embedded in rip rap, serve as a geologic undertaking (BRUUN smoothclosure base for the steel JOHANNESSON,1976; BRUUN and KJELS- drop gates. Box Girders: These consist of TRUP,1981; WATSON et al., Road-Bridge 1975). concrete 45 m in Rock borrowwas importedover a period of prestressed beams, length four and on the construction (Figure 30). The spaces within the box girders years stockpiled of the islands (Figure31). It subsequentlywas placed protect part hydraulic gate-operating machineryfrom corrosivesea spray.

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Figure29. Simplified cross section showing foundation-protection components for the EasternScheldt barrier: (1) anticipated erosion gullywhere seabed protectionends, (2) concrete-weightederosion mat (see Figure27), (3) lower graded-filter mattress(see Figure19), (4) uppergraded-filter mattress, (5) levelingblock mattress, (6) asphaltslabs, (7) gradedrip-rap sill, (8) gravelbag, and (9) prefabricatedconcrete pier. (After DOSBOUWv.o.f., 1983).

Upper Beams: These provide additional reflected both innovativethought and effective structuralsupport between piers (Figure 30). communication between geologists and en- Capping Units: Capping units add the gineers, and have important application to necessary height to the piers, to accomodate many aspects of future coastal and offshore the gate structure. construction. The use of prefabricated com- Gates: Each of the 62 steel gates was custom ponents and placement methods to the extent made to fit the exact as-builtdimensions of the implemented on the Eastern Scheldt barrier pier openings. The span of each gate was ap- (and foundations), represents an important proximately42 m, while the height of each gate breakthroughin open-water construction. varied, naturally, according to the change in If the trend of ice-cap melting and sea-level depth of the channel profile (between 5.9 m rise continues,it is envisagedthat severalworks and 11.9 m). The gates, like other parts of the of similar scale may have to be undertakenin superstructure,were installed with the 1600 other partsof the world. ton floating crane, Taklift4 (Figure 33). Modifiedplans for the EasternScheldt demon- Pier Grouting and Ballasting: To provide strate man'sincreasing concern for his environ- uniform load-bearing conditions over the en- ment. tire base area of each pier, the space between Finally,the cost-benefitjustification of the Delta the pier base slab and the upper foundation Projectdemonstrates the considerableeconomic mattress,was grouted.Finally, to ensure added value of coastal land in industrializedparts of stabilityto piers, these wereballasted with sand. today'sworld. This completedthe barrier. ACKNOWLEDGEMENTS CONCLUSIONS The authors gratefullyacknowledge the ex- Thisbrief summary does notbegin to dojustice tensive informationand help providedby tech- to the complexityof investigation,design and nical and other personnel of The Netherlands constructionproblems faced by project scien- Ministry of Transport and Public Works, tists and engineers.The Delta Worksrepresent, Rijkswaterstaat, and the joint-venture con- without question, the state of the art of storm- struction consortiums of Dosbouw v.o.f., and surge protection. Heavy constructionin open Ostem v.o.f. water, subject to the effects of waves and cur- The authors greatly benefited from advice, rents, and on soils of highly-variablecharacter translations,contacts and/or reviews provided and poor engineeringproperties is, at best, dif- by P.Bruun, R.R. Lemon, I. Knox, J. Liera, M. ficult. Rolland-Dogger, H. Th. Verstappe, and H.J. Newly-developeddesigns and techniques, par- Verhagen.C. Mischler, L. Pitts, S. Pennell and ticularlyin the area of foundationpreparation W.Watkins and staff are thankedfor their help and the use of foundationprotection mattresses, in presentation.

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Figure30. Foundationand structuralcomponents of the EasternScheldt barrier. (1) prefabricatedgate-support pier, (2) rip-rapapproach abutment, (3) supportbeam for gate-controlequipment, (4) hydrauliccylinders for gate operation,(5) cappingunit, (6) upperpier-connecting beam, (7) lift gate, (8) lowersill base, (9) road,(10) roadbox girders,(11) power supplyand machineryfor gate operation,(12) hollow,ballasted section for sill beam,(13) armor-stone,rip-rap protection for sill, (14) core-stonesill support,(15) sand-ballastedpier base, (16) sill-beamstops, (17) upperfoundation mattress, (18) groutedsection between mattress and pier base, (19) blockmattress, (20) bottommattress, (21) compacted-sandfoundation bed,and (22) gravelbag. (After DOSBOUWv.o.f. (1983), drawing by Rudolf Das (1982), Rijkswaterstaat Meetkundige Dienst AfdelingReprografie).

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Figure 33a. All large superstructure components of the East- ern Scheldt barrier were installed by the 1,600 ton floating Taklift 4. (Air photographs by Bart Hoffmeester, Aerocamera. Rijkswaterstaat Meetkundige Dienst Afdeling Reprografie). (a) installation of a gate.

Figure31. Some five milliontons of rock rip rap were im- ported from quarriesin Belgium,Finland, Germany, and Sweden to pretect the foundationsand lower sections of structural components of the Eastern Scheldt barrier. (RijkswaterstaatMeetkundige Dienst Afdeling Reprografie).

Figure 33 cont. (b) Installation of a road-section box girder (Photograph shows the barrier across one of the three channel sections of the Eastern Scheldt estuary).

sponse of Earth Dams to Strong Earthquakes. Geotechni- que, 17, (3), 181-213. Figure 32. Larger armorstone rip rap had to be placed by a special vessel to avoid damage to piers. (Photograph by Bart ANTONISSE, R, 1986.De kroonop het Deltaplan. Stormvloed- Hofmeester, Aerocamera, Rijkswaterstaat Meetkundige kering Oosterschelde.Het grootste waterbouwprojectaller tij- Dienst Afdeling Reprografie). den MCMLXXX7V.Elsevier Boeken B.V., Amsterdam/Brussel, 224p. BJERRUM, L., 1973. Geotechnical Problems Involved in Research support was provided by Florida Atlantic Foundations of Structures in the North Sea. Geotechnique, University and the Coastal Education and Research 23, (3), 319-358. Foundation [CERF]. BOEHMER, J.W., 1978. Geotechnical Oosterschelde Studies and Some Unexpected Aspects. In: Foundation As- pects of Coastal Structures.Vol. 1, International Symposium LITERATURE CITED on Soil Mechanics Research and Foundation Design for the Oosterschelde Storm Surge Barrier. Delft, The Nether- lands, 1.3, 1-16. AMBRAYSEYS, N.N, and SARMA, S.KI, 1967. The Re-

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This content downloaded from 132.206.27.25 on Sat, 6 Apr 2013 15:43:26 PM All use subject to JSTOR Terms and Conditions Storm-SurgeProtection in The Netherlands 763

Delft UniversityPress, The Netherlands,pp. 627-639. NIEUWENHUIS,J.K., 1987a. Stability and Deformation of ClosureFoundations. In: van Aalst, W. (EditorialCo-ordinator),The Closureof Tidal Basins, Delft University Press,The Netherlands,319-341. NIEUWENHUIS,J.K., 1987b. Earthquake Induced Loads. In: van Aalst, W. (Ed. Co-ordinator), The Closure of Tidal Basins.Delft UniversityPress, The Netherlands,pp. 307- 318. PILARCZYK,KW., 1987a.Ice Induced Loads. In: van Aalst, W. (Ed. Co-ordinator), The Closure of Tidal Basins. Delft UniversityPress. The Netherlands,pp. 295-305. PILARCZYK,KIW., 1987b. Local Scour. In: van Aalst, W. (Ed. Co-ordinator), The Closure of Tidal Basins. Delft UniversityPress, The Netherlands,pp. 387-405. PILARCZYK,K.W., 1987c Filters. In: van Aalst, W. (Ed. Co-ordinator), TheClosure ofTidal Basins. Delft University Press,The Netherlands,pp. 467-489. Figure33 cont.(c) A close-upof the pier-supported,lift-gate sectionsof the barrier. RIJKSWATERSTAAT,1987. The Compartmentalization Worksin the Eastern Scheldtfor the Benefit of the Natural Environment, Water Management and Shipping. Dutch BRUUN, P., and JOHANNESSON,P., 1976. Parameters GovernmentPrinting Office, 2nd Impression, 32p. AffectingStability of RubbleMounds. Journal Waterways, Harbors and Coastal Engineering,Vol. 102, WW2. SCHELLEKENS,J.P.; WOUTERS, J., andVRIJLING, J.K., 1980.Transition Structures between Barrier and Dikes.In: BRUUN,P., and KJELSTRUP,S., 1981.Practical Views on HydraulicAspects of CoastalStructures, Part 2: Developments the Designand Construction of MoundBreakwaters. Coas- in HydraulicEngineering. Delft UniversityPress, pp. 121-139. tal Engineering,5. SEED,H.B., 1979. Considerations in the Earthquake-Resis- de JONG,DJ.; LEEWIS,R.J.; MISDORP, R; STORTEL- tantDesign of Earthand Rockfill Dams, Geotechnique,29, DER, P.B.M.,and VISSER, J., 1987.Ecological Conditions. (3), 215-263. In: van Aalst, W. (Ed. Co-ordinator), The Closure of Tidal Basins.Delft University Press, The Netherlands,pp. 115-134. SMITS,F.P.; ANDERSEN, K.H., and GUDEHUS, G., 1978. Pore Pressure Generation. In: FoundationAspects of Coas- de LEEUW,E.H., 1976. Results of LargeScale Liquefaction tal Structures.Vol. 1. InternationalSymposium on Soil Tests. International Conference on Behaviour of Offshore Mechanics Research and Foundation Design for the Structures,Boss '76,Trondheim, Vol. 11,65-84. OosterscheldeStorm Surge Barrier. Delft, The Nether- lands,11.3, 1-16. de MULDER,E.FJ., andvan RUMMELEN, F.F.F.E., 1978. EngineeringGeology: Construction of a StratigraphicModel. van AALST,W., and BRUINSMA,J., 1987.Waves. In: van In: FoundationAspects of Coastal Structures.Vol. 2. Interna- Aalst, W., (Ed. Co-ordinator), The Closure of Tidal Basins. tionalSymposium on SoilMechanics Research and Founda- Delft UniversityPress, The Netherlands,pp. 53-71. tion Design for the OosterscheldeStorm Surge Barrier. Delft, The Netherlands,V.lb, 1-14. v.d. BURG, J.C., and NIEUWENHUIS, J.K., 1987. GroundwaterFlow. In: van Aalst, W. (Ed. Co-ordinator), DOSBOUW v.o.f., 1983. TheStorm Surge Barrierin the East- The Closure of Tidal Basins. Delft University Press, The ern Scheldt,for Safety and the Environment.A joint publica- Netherlands,pp. 447-466. tion by the Oosterschelde StormvloedkringBouwcombanie and 1987. Measurementof (DOSBOUW)v. o.f. and VoorlichtingVerkeer en Waterstaat, van de REE, W., STUIP, J., 32p. Currents.In: van AalstW., (Ed. Co-ordinator).The Clos- ure of Tidal basins, Delft UniversityPress, The Nether- ENGEL,H., 1980.Overall Picture of the Project.In: Hydraulic lands,147-168. Aspect of Coastal Structures. Part 1. Developments in Hydraulic Engineering related to the design of the vander SCHAAF,T. andOFFRINGA, G., 1980.Outline of OosterscheldeStorm Surge Barrierin the Netherlands.Delft Construction Methods. In: Hydraulic aspects of Coastal UniversityPress, The Netherlands,pp. 3-16. Structures.Part 2. Developmentsin HydraulicEngineering relatedto the design of the OosterscheldeStorm Surge ENGEL,H., 1987.Perface. In: van Aalst, W. (Ed. Co-or- Barrierin the Netherlands.Delft UniversityPress, 141-171. dinator). TheClosure of TidalBasins. Delft UniversityPress. The Netherlands,743p. van WESTERN, J.M., 1987. Closure of the Brouwer- shavenschegat by the constructionof the BrouwersDam. HUIS in 't VELD, J.C., 1987a.Gradual Closures. In: van In: van Aalst, W. (Ed. Co-ordinator), The Closure of Tidal Aalst, W. (Ed. Co-ordinator), The Closure of Tidal Basins. Basins,Delft UniversityPress, The Netherlands,pp. 665- Delft UniversityPress, The Netherlands,pp. 601-609. 727. HUIS, in 't VELD, J.C., 1987b.Sudden Closure. In: van VERMEIDEN,J. andLUBKING, P., 1978.Soil Investigation. Aalst, W. (Ed. Co-ordinator), The Closure of lidal Basins. In: FoundationAspects of CoastalStructures. Proceedings

Journalof CoastalResearch, Vol. 6, No. 3, 1990

This content downloaded from 132.206.27.25 on Sat, 6 Apr 2013 15:43:26 PM All use subject to JSTOR Terms and Conditions 764 Watsonand Finkl

Vol.2. InternationalSymposinum on Soil Mechanics Research WATSON,I.; FISCHER,J.A., and URLICH,C.M., 1975. and FoundationDesign for the OosterscheldeStorm Surge Geotechnicalaspects of rockborrow for largebreakwaters. Barrier.Delft, The Netherlands,V.IA, 1-32. 7thAnnual Ofshore TechnologyConference, Texas. OTC 2392,Vol. 111,553-563. VRIJLING,J.K., and BRUINSMA, J. 1980.Hydraulic Bound- ary Conditions.In: HydrauicAspects of CoastalStructures, WATSON,I., andKRUPA, S., 1984.Marine drilling explora- Part1. Developmentsin Hydraulic Engineering related to the tion, technicaland environmentalcriteria for rig selection. design of the OosterscheldeStorm Surge Barrierin the Litoralia,1(1), 65-81. Netherlands.Delft UniversityPress, The Netherlands,pp. 109-133. WEENINK,M.P.H., 1958. A theoryand methodof calcula- tion of wind effects on sea levels in a partlyenclosed sea WALTHER,A.W., 1987. Introduction. In: van Aalst, W. (Ed. withspecial application to the southerncoast of the North Co-ordinator),The Closure of7idal Basins. Delft University Sea. KNMI,Med. en Verh.,No. 73, 27p. Press,The Netherlands,pp. 9-14.

O ZUSAMMENFASSUNG0 Ein Multi-Milliarden-Dollar-Komplexvon Kiistenbauwerkenschiitzt die Delta- und Astuar-Regionender suidwest- lichen Niederlande vor der Wiederholungder Sturmflutereignissevon 1953, bei denen 1835 Menschen ums Leben kamen.Insgesamt sind seit 1717 8 grosse Sturm-flutkatastrophenbeleget. Das Deltaprojektgewiihrt bereits seit 1986 vollen Sturmflutschutz,obwohl immernoch Teile davon unvollendetsind. Als eines der gr6ssten zivilen Bauprojekete der Erder haben seine 11 Haupt- und zahlreichenNebenabschnitte die Aufgabe (1) drei Hauptistaure abzuschneiden und damit die Kiistenlinien um ca. 720 km zu verkiirzen,(2) als Verbindung zwischen Schelde und Rhein einen gezeitenfreien Wasserwegzu schaffen, der die Schiffahrtzwischen Antwerpen und Rotterdam (120 km), zwei der grossten Hiifen der Welt, erleichtert,und (3) Teile der Deltafliche zu schiitzen. Diese Fallstudie beschreibt die geologischen und Fundamentierungs-probleme,die Planung und den Bau, die Vor- untersuchungenund Vorbereitungender Fundamente,die Methoden der Konstruktionund die Wechselwirkung zwischenUntergrund und Aufbauten. Hauptgegenstand ist die reisige Kontrollbarrierevon 7,5 km Liinge,welche 1986 die 6stliche Scheldemiindungabschloss und die bei weitem der schwierigsteund teuerste Bauabschnittwar. Hier und in anderenTeilen des Deltas haben die mangelndeErfahrung mit solchen Bauwerken,die komplexelokale Geologie und die starken Gezeitenstr6mungendazu gefuihrt,dass allein die Fundamentierung80% der gesamten Bauzeit in Anspruchnahm. Die dabei neu entwickeltenTechniken werden in Zukunftweltweit bei Kiisten- und Seebauwerken verwendt werden. - Dieter Kelletat, Essen, FRG. 0 RESUMeO C'est un complexe de constructionsc6tieres coOtantplusieurs billions de dollards qui protege la Hollande d'une rip6tition de la catastrophede 1953 qui fit 1835 morts. Depuis 1717 huit invasionsde la mer avaient&t6 enregistrdes. Le projet de Delta ne protege efficacementle paysde l'inondationque depuis 1986,mais certainessections sont encore en construction.Ce projet d'ing6nieriecivile ets un des plus vastes du monde. II a onze composantes majeureset de multiples autres, secondaires. Leur fonction et de: (1) fermer les principauxestuaires, ce qui raccourcitla ligne de rivageA 720 km;(2) crderun acces non soumisa la marie au "Scheldt-Rhein"pour faciliterl'acces aux naviresd'Anvers a Rotterdam (120 km), deux des plus importants ports du monde et (3) assurer une prdservationpartielle de l'environmentdu delta. Cette historie de cas concerne la gdologie et les problemes de fondations, la planification et les sequences de construction,la recherchesur le site et la prdparationdes fondations, les methodes de constructionet l'interaction fondations-structures.Le point cl est la digue-barrierede protection a grandeechelle termindeen 1986, traversant sur 7,5 km l'estuairede Scheldtde 'Est qui constitue de loin la partie la plus difficile et la plus co teuse du projet. Ici comme dans d'autresparties du delta, les forts courantsde marie et la grandevariabilitd des materiauxgeologiques peu appropri6saux construction d'ouvragesont fait que 80% du temps de la construction ont dtd n6cessaires a des seules fondations. Les nouvelles ont dtd pour le projet ont une l'establissement techniques qui ddvelopples application A l'6chelle mondiale pour les futures constructions c6tidres et offshore. - Catherine Bressolier, Geomorphologie EPHE, Montrouge, France.

88040 received 7 February1989; accepted in revision 5 January1990. To be published in Dutch and English in 1991as Special Issue No. 10.

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