FOUNDATIONS FOR THE NEW INTERNATIONAL …

1 1 FOUNDATIONS FOR THE NEW INTERNATIONAL airport IN bangkok , THAILANDASCE Seattle SectionGeotechnical GroupMay 16, 2009 THAILANDB engt H. FelleniusFOUNDATIONS FOR THE NEW INTERNATIONAL airport IN bangkok , THAILANDB engt H. FelleniusA presentation to the ASCE Seattle Section 2009 Spring Seminar onRecent Developments and Case Histories in Deep Suvarnabhhumi airport , the new INTERNATIONAL airport in bangkok , thailand , covering an area of 8 Km by 4 Km (8,000 acres), is located in a former swamp, a flat marine delta about 30 Km outside bangkok . The soil profile consists of a thin weathered crust on typical soft to stiff, compressible bangkok clay deposited on a sand layer at a depth of about 25 m extending to about 47 m. Below the sand lies an about 10 m thick layer of hard silty clay followed by very dense sand to large depth. Most of the area is devoted to runways, roadways, and parking, which required extensive ground improvement to minimize settlement.

2 The structures consist of several units sharing footprints: terminal building, conourse, trellis structure, parking garage, and elevated roadways. The structures are founded on three types of piles installed to the sand below the clay layer, 1,000 mm bored pile, 600 mm diameter bored piles, and 600 mm driven cylinder piles. The stress-bulbs from the various FOUNDATIONS overlap resulting in a complicated settlement analysis. A total of 25,000+ piles were installed. The design of the airport started in 1995 and construction was completed in 2005 at a total cost of close to us$30 billion. The lecture will present aspects of the soil improvement work, analysis of results from pile tests, and the design of the piled FOUNDATIONS for capacity, settlement, and downdrag. The main part of the presentation consists of information quoted from papers published in Geotechnical Engineering Special Issue, , No.

3 3, December New INTERNATIONAL airport , bangkok ThailandFoundation Design by TAMS/Earth Tech, NYwith Dr. Bengt H. Fellenius as outside consultantThe presentation is primarily based on papers published in the Special Issue of the Journal of South-East Asian Geotechnical Society, "Geotechnical Engineering", December, 2006, as listed in the next , S. 2006. Bored piles and bi-directional load tests. Special Issue of the Journal of South-East Asian Geotechnical Society, December 2006, 37(3) , , Visser, , and deZwart, , 2006. Geotechnical History of the development of the Suvarnabhumi INTERNATIONAL airport . Special Issue of the Journal of South-East Asian Geotechnical Society, December 2006, 37(3) , and Lin, , 2006. Geotechnical History of the development of the Suvarnabhumi INTERNATIONAL airport . Special Issue of the Journal of South-East Asian Geotechnical Society, December 2006, 37(3) , , 2006.

4 Design and construction of ground improvement works at Suvarnabhumi INTERNATIONAL airport . Special Issue of the Journal of South-East Asian Geotechnical Society, December 2006, 37(3) , I., Du, M. and Buttling, S, 2004. Deep FOUNDATIONS For New INTERNATIONAL airport Passenger Terminal Complex in bangkok . Proceedings of the Fifth INTERNATIONAL Conference on Case Histories in Geotechnical Engineering, New York, April 13-14, Paper , 11 INTERNATIONAL AirportAn 8 Km x 4 Km area close to the Gulf of Thailand66 Data from: Fox, Du, and Buttling, (2004), Buttling (2006), Moh and Lin (2006), Seah (2006), Cortlever, Visser, and deZwart (2006)Basic Soil Parameters051015201,0001,5002,000 Density, t (%)Depth (m)05101520050100150 Water Content, wn (%)Depth (m)051015200255075100 Vane Strength, u (KPa)Depth (m) u FirmStiff to Very StiffVery softtoSoftwP 30wL 80 - 100 FILL70510152005101520 Virgin Modulus Number, mDepth (m)05101520050100150 Reloading Modulus Number, mrDepth (m)CompressibilityRed Lines show distribution for designCircles are data pointsCR = Cc /(1+ e0 )m = ln10 (1 + e0 ) Ratio, CRDepth (m)88 Comparison between the Cc /e0 approach and the Janbu Modulus Number methodData from a 20 m thick sedimentary RATIO, e0 COMPRESSION INDEX, CcDo these values indicate a compressible soil, a medium compressible soil, or a non- compressible soil?

5 RATIO, e0 VIRGIN MODULUS NUMBER, mThe Cc -e0 approach (based on Cc ) implies that the the compressibility varies by 30 %. However, the Janbu methods shows it to vary only by 10 %. The modulus number, m, ranges from 18 through 22; It would be unusual to find a clay with less (mm)Settlement of the Ground Surface Observed at airport SiteRegional settlement occurs at and around the airport area due to mining of ground waterStart of design work10 Current and Future (long-term)Pore Pressure Distribution0510152025303540455001002003 00400500 Pore Pressure (KPa)Depth (m)Long-TermShort-Term (Current)0102030405060701975198019851990 1995200020052010 YEARD epth to Graounwater Table (m)DesignPhaseConstructionPhaseNearby Observations of Groundwater TablePumping (mining) of groundwater has reduced the pore pressures in the bangkok delta resulting in significant regional settlement.

6 In 1996, coinciding the beginning of the design process, pumping in the area was stopped. Pore pressure measurements indicate that the desired effect is being reached; the pore pressures are rising and the distribution may become hydrostatic in the DEPTH (m)132a- 14m217 - 26m216a- 39m115 -153m209 -159m111 -161m501a-180m912 -206m114a-261m618 -267m606 -301m501b-365m132b-442m114b-480m1925 1935 1945 1955 1965 1975 1985 1995 2005 2015 SHALLOW WELLSDEEP WELLSThe lowering of the groundwater table due to mining of water in the bangkok delta is not unique. Below is a compilation of depth to the water table measured in the San Jacinto-Houston-Pasadena area in Texas. 12-83 KPa105 KPa34 KPa 85 KPa105 + 34 + 85 = 224 - 83 141 KPa110 m38 m74 mBriaud et al.

7 2007; Fellenius and Ochoa 2008050100150200250300350193619461956196 61976198619962006 SETTLEMENT (mm)YEARSETTLEMENT OF MONUMENT RELATIVE TO BENCHMARK050100150200250300350400110100 YEARSETTLEMENT (mm) 1936 1937 1940 1945 1950 1960 1975 2000 LINEAR PLOTLOWER SCALELOGARITHMIC PLOTUPPER SCALE19361946195619661976198619962006130 50100150200250300350400110100 YEARSETTLEMENT (mm) 1936 1937 1940 1945 1950 1960 1975 2000 DEPTH TO WATER TABLESETTLEMENT0255075100125 DEPTH TO WATER TABLE (m)Monument onlyMeasured depths to water table and measured settlement of the Monument plus estimated settlement of the Monument had there been no drawdown of the water in the San Joaquin Valley in California:197719551925 Subsidence at San Joaqu in Valley, CaliforniaDevin Galloway and Francis S. Riley, Geological SurveyApproximate location of maximum subsidence in United States identified by research efforts of Joseph Poland (pictured).

8 Signs on pole show approximate altitude of land surface in 1925, 1955, and 1977. The pole is near benchmark S661 in the San Joaquin Valley southwest of Mendota, California,1515 Circles are preconsolidation data pointsDashed green line shows distribution for design Short-term : Effective stress distribution at time of design Long-term : Effective stress distribution after groundwater table is raised05101520050100150200 Stress (KPa)Depth (m)Long-term '0 'c Short-term '0 Stress ProfileBut back to bangkok :1616 MainTerminalAcess RoadsConcourses17-400-300-200-1000100200 30040050060004080120160200240 DAYSSETTLEMENT (mm)Construction PeriodFull Height = mCalculated Immediate SettlementCalculated Total SettlementMeasured Total SettlementHEIGHT (m) Consolidation Settlement40 m10 mFirst a few words on the soil improvement workMeasured and Calculated Settlement at center line of for a m Embankment during 200 days.

9 No drains, , incomplete at center line of a Embankment on Wick DrainsAVERAGE MEASURED SETTLEMENTDESIGN CURVE FOR THISSURCHARGE (75 KPa ) mFINAL HEIGHTOF FILLSETTLEMENT (mm)Wick Drains Installed 200 daysFor reference, the curve of the "undrained" embankment19 Settlement and Horizontal Movement for the m EmbankmentTime from start to end of surcharge placement = 9 monthsObservation time after end of surcharge placement = 11 monthsW ICK DRAINS TO 10 m mW ICK DRAINS TO 10 m DEPTHWICK DRAIN Settlement was monitored in center and at embankment sides and horizontal movement was monitored near sides of embankment2020 Horizontal Movement versus Settlement at Different Test LocationsHORIZONTAL MOVEMENT (cm)SETTLEMENT (cm)2121 Lateral spreadingSettlement with risk for downdragThe ProblemPiles22222323 These photos of the bridge FOUNDATIONS illustrate a common problem affecting maintenance ($$$!)

10 , as well as, on occasions, being one compromising problem is not limited to bridge foundations2525 Consolidation Coefficient, cv (m2/s)Consolidation Coefficient, cv (m2/s)Settlement after 4 months as a function of the Consolidation Coefficientand Drain SpacingDegree of Consolidation after 4 months as a function of the Consolidation Coefficientand Drain SpacingvvcHTt2=SETTLEMENT (m)CONSOLIDATION (%)2626 The clay is soft and normally consolidated with a modulus number smaller than FOUNDATIONS the trellis roof, terminal buildings, concourse, walkways, etc. are placed on piles. The stress-bulbs from the various FOUNDATIONS will overlap each other s areas resulting in a complicated settlement ,000 mm Bored Piles600 mm Bored Piles600 mm Driven Closed-toe Cylinder Piles1,000 mm Bored Piles600 mm Bored Piles2727 Horizontal soil movement ("lateral spreading") toward piles can be criticalTRELLI S ROOF PILE CAPFOOTPRINTS OF PILE CAPS FOR TERMI NAL BUILDING NEAR TRELLI S ROOFTYPICAL FOOTPRINT LAYOUT OF TRELLIS AND BUILDING FOUNDATIONSA dditional features, such as Embankments, Aprons, Concourse FOUNDATIONS , Area Fills, etc.