EuroGeo4 Paper number 315 DESIGN OF PILED EMBANKMENTS, CONSIDERING THE BASIC STARTING POINTS OF THE BRITISH STANDARD BS8006

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1 EuoGeo4 Ppe numbe 315 DESIGN OF PILED EMBANKMENTS, CONSIDERING TE BASIC STARTING POINTS OF TE BRITIS STANDARD BS8006 Suznne J.M. Vn Eekelen 1 & Adm Bezuijen 1 Delte. (e-mil: Suznne.vnEekelen@Delte.nl) Delte/TU-Delft. (e-mil: Adm.Bezuijen@Delte.nl) Abtt: At the moment, Duth Stndd fo the deign of piled embnkment i in peption. Fo thi pupoe, exiting deign model e onideed nd vlidted. Thi ppe nlye the bi tting point of the Bitih Stndd BS8006, onening the deign of piled embnkment. The mjo fou tting point of BS8006 e: Mton fo the lod on the pile p, no uppot of oft oil, n umption fo the line lod W T on the geoyntheti einfoement tip between two djent pile p, nd teny eqution, giving the eltion between the line-lod W T nd the tin nd tenile tee in the geoyntheti einfoement. It i onluded tht the Bitih Code h fundmentl poblem. The oeffiient peented in BS8006 fo the Mton eqution ditinguih hing on end-being pile nd on fition pile, whih doe not gee with the umption of no uppot of the oft oil; the eqution e not fully nd the vetil equilibium i not genelly tified: the totl lod doe not equl the um of the lod on the geoyntheti einfoement nd on the pile. The ppe finlly popoe n dpttion of the eqution o tht the method beome fully nd the vetil equilibium i tified. Keywod: Piled embnkment, hing, oil impovement, geoyntheti, geogid einfoement, geomtte INTRODUCTION Piled embnkment e beoming moe popul in the Nethelnd. At the moment, Duth Stndd fo the deign of piled embnkment i in peption. Fo thi pupoe, exiting deign model fo the deign of the einfoed embnkment bove the pile e onideed nd vlidted. Thi ppe onide the bi tting point of Bitih Stndd BS8006 hpte 8, epeilly hpte 8.3, onening the deign of piled embnkment. The Bitih ode BS8006 mke fou umption to lulte the lod on the geoyntheti einfoement in piled embnkment (figue 1): 1. The diet lod on the pile p my be lulted by uing the eqution of Mton fo pipe, dpted fo piled embnkment,. No uppot of oft oil 3. The lod on the einfoement (p ) i tnfeed into line-lod W T on the tip of einfoement between djent pile p. BS8006 give eqution fo thi line-lod W T 4. The eltion between the line-lod W T, the tin ε nd the tenile te in the geoyntheti einfoement i given by the teny eqution: T p W T ( ) ε (1) whee T p i the tenile te in the einfoement in kn/m, W T i the line-lod in kn/m on the einfoement tip between two djent pile, i the ize of pile p ide in m, the ente to ente ditne between two pile in m (ee Figue 3) nd ε i the vege tin in the einfoement. Thi ppe onide minly the fit thee umption. Fit, the lod dietly tnfeed to the pile, lulted with the eqution of Mton (umption 1) i onideed, inluding the umption of no uppot of oft oil (umption ). Then the lod tnfeed to the geoyntheti einfoement (p in kp nd W T in kn/m, umption 3) i lulted fom both the umption of vetil equilibium nd the eqution of the Bitih Stndd. Finlly the two eulting expeion fo W T e omped. TE LOAD TRANSFERRED DIRECTLY TO TE PILE CAP p : MARSTON A in mot model fo the deign of piled embnkment, BS8006 tt with dividing the totl lod into two pt. The fit pt i the lod p (kp) tnfeed dietly to the pile. Thi lod i lge thn σ v γ + p, the vege vetil lod ued by the embnkment nd the uhge lod, due to the hing effet. In thi eqution, γ i the weight of the fill in kn/m 3, p i the uhge lod in kp nd i the thikne of the embnkment in m. The eond pt of the lod, p (kp) i the lod ied by the einfoement in between the pile. Thi p h not been woked out expliitly in the Bitih Stndd. To deive p, the lod tnfeed dietly to the pile, BS8006 be itelf on the D eqution of Mton fo lod on n infinitely long pipe (ee fo exmple Love & Millign 003). Mton found: 1

2 σ ' v C EuoGeo4 Ppe numbe 315 () Whee, C i the hing oeffiient. Fo the e of piled embnkment, BS8006 ume tht it i good ppoh to que the ight pt of thi eqution of Mton (BS8006 pge 105, in odne with Jone et l, 1990): C σ ' v Fo thi dpted Mton eqution, BS8006 give the following hing oeffiient: (3) End-being pile Fition nd othe pile C (4) C (5) einfoement embnkment A uhge lod p A A Lod potion A i tnfeed to pile give p (kp) on the pilep, Lod potion B (weight of oil below the vitul h) give lod p (kp) woking on the einfoement. Thi lod p i tnfeed by the einfoement A to the pile. BS8006 doe not lulte p B B B dietly, but wok with the line p p lod W T on the einfoement tip jut between two djent pile p. C C C C In BS8006, C lod C potion C 0 oft oil pile p beue BS8006 ume no uppot of oft oil. Figue 1. All deign model fo piled embnkment divide the lod into potion In elity the nge fo nd will be 0.3 < < 1.5 nd 0.90 < < leding to 0.03 < / < It w obeved tht: It i inonitent to ditinguih C fo end-being pile nd fo fition pile, while it i lo umed tht the oft oil doe not give ny uppot. Auming no oft oil uppot ( gp below the mtte), the geoyntheti einfoement hould not feel whethe pile i end-being o fitionl. Fo eliti vlue fo /, thee i not muh vition in the vlue of p /σ v (ee figue, left bottom gph) Fo elly thin embnkment, (y 0.1 m, o / 3 to 1.5), it hould be expet tht p /σ v ppohe 1.0. Thi i not the e, hown in the ight bottom gph of figue. It i onluded tht the dpted Mton eqution nd it vlue fo C e not vlid ove the whole nge of poible vlue of / in piled embnkment. Sine it w deived fo pipe in the oil, it i likely tht the oiginl Mton eqution nd the eulting vlue of C only pply to mll vlue of /. It i onluded tht the dpted eqution e diputble. oweve, the vlue of p lulted with the dpted Mton eqution i only ued n input pmete fo the lultion of the lod on the einfoement. The lod on the pile itelf will be the entie lod, nmely both the lod on the geotextile (tnfeed to the pile by the geotextile) nd the lod dietly on the pile.

3 EuoGeo4 Ppe numbe 315 hing oeffiient C end-being pile fition nd othe pile / hing oeffiient C / /igm'v /igm'v / Figue. Left: eliti vlue fo / give vey imil vlue fo p /σ v. Right: fo exteme vlue of / (thin embnkment), the tio p / σ v doe not ppoh the expeted vlue of / TE VERTICAL LOAD ON TE GEOSYNTETIC REINFORCEMENT p BS8006 doe not lulte p dietly. Afte giving the bi eqution fo vetil equilibium, the eltionhip between p nd the line lod W T will be lulted in thee wy: Fom vetil equilibium in ombintion with the D ppoh of W T Fom vetil equilibium in ombintion with the ppoh of W T Fom the line-lod W T given by BS8006 in ombintion with the D ppoh of W T Fom the line-lod W T given by BS8006 in ombintion with the ppoh of W T Vetil equilibium The totl lod (kn) on one que * i: γ + p ( ) The lod (kn) tnfeed dietly to pile p i: w The lod (kn) on the geoyntheti einfoement i: w ( ) (6) (7) (8) Vetil equilibium give: γ + p (9) ( ) ( ) And thu: γ ( + p) (10) The eltionhip between the line-lod W T nd vege lod on geoyntheti einfoement p BS8006 doe not lulte the vege lod on the geoyntheti einfoement p dietly, but give eqution to lulte the line-lod W T on einfoement tip jut between two djent pile p. Let u fit onide the eltionhip between thi p nd W T, whih n be detemined in two wy, nmely D, in odne with D Jone et l (1990), in odne with Love & Millign (003) The next etion deibe thee D nd eltionhip. 3

4 EuoGeo4 Ppe numbe 315 BS8006 ume (on pge 106, below tble 8) tht the lod on the einfoement n be onideed line lod W T (kn/m ) woking on the tip of einfoement between djent pile p. Tht men tht uh line lod W T wok on the hded pt in figue 3b (top o bottom). The mount of lod ied by uh hded pt depend on whethe D o ppoh i dopted. BS8006 doe not define whih ppoh i hoen: D o, but we will how tht BS8006 ue the D ppoh. D in odne with Jone et l (1990) Sevel utho wote tht BS8006 i bed on Jone et l (1990). Jone gve D eltionhip between the line lod W T nd p. (figue 3b on top). Thu, (teny) tip jut between two pile p, with width, i umed to y the whole lod on the einfoement within one que (-)*, o: WT D : ( ) WT ( ) (11) Thi i in odne with fo exmple Le ello (007). When thi eqution i ombined with the equiement of equilibium (eqution (10)), it i found tht: ( p) p γ + D : WT * ( p) γ + γ + (1) O: D : WT ( γ + p) (13) Whee p p γ + ' (14) Thi i in odne with eqution () of Jone et l (1990) in odne with Love & Millign (003) Aoding to fo exmple Love & Millign (003), BS8006 ume tht the hded pt in figue 3b (bottom) eh y line lod W T (kn/m ) equl to qute of the totl lod on the geoyntheti einfoement (thu 0.5*p ). Love & Millign (003) doubt thi umption fo non-bixil gid. Thu, (teny) tip jut between two pile p, with width, i umed to y hlf of the lod on the einfoement within one que *, o: WT : ( ) WT ( ) (15) + Thi i in odne with fo exmple Love & Millign (003), Stewt (005) nd Ruell nd Piepoint (1997). When thi eqution i ombined with the equiement of equilibium (eqution (10)), it i found tht: ( ) ( ) ( γ + p ) : WT (16) o: 3 D : WT 0.5 ( γ + p)( + ) (17) W T oding to BS8006 nd D nd eltionhip W T nd p The Bitih Stndd ditinguihe full hing, > 1.4(-) nd ptil hing, 0.7(-) 1.4(-). Thee two e e onideed eptely. BS8006 doe not ept < 0.7(-) to enue tht lolized diffeentil defomtion nnot ou t the ufe of the embnkment. Full hing The Bitih Stndd give the following eqution to detemine W T, (ignoing ptil fto): p WT ( ) γ γ 1. 4γ ( ) In ombintion with the eqution fo epetively D nd -line-lod (eqution (11) nd (15)) thi give: (18) 4

5 D : : W T 1.4γ WT + ( ) ( ).8γ + EuoGeo4 Ppe numbe 315.8γ p γ + ( + ) (19) The lt eqution i lo found by fo exmple Love & Millign (003), Stewt (005) nd Ruell nd Piepoint (1997). Figue 3. Jone et l (1990), figue W T i ting upon einfoement tip between two djent pile p. BS8006 dopt thi figue of Jone in BS8006-figue 70. Figue 3b. W T i ting on hded e. Intepettion of figue 3 oding to (on top) D eqution () fom Jone et l (1990) nd (bottom) eqution fom fo exmple Love & Millign (003) Ptil hing Fo 0.7(-) 1.4 (-), ptil hing i uppoed to ou. BS8006 give fo thi e: Pile p - D, in odne with fo exmple Jone et l 1990, Sevink 006 nd Le ello, 007, in odne with fo exmple Love & Millign 003, Stewt 005 nd Ruell nd Piepoint W p γ + γ ( γ + p) ( p) T + (0) In ombintion with the eqution fo epetively D nd -line-lod (eqution (11) nd (15)) thi give: D : : WT WT + ( γ + p) ( γ + p) + (1) TE DEMAND OF VERTICAL EQUILIBRIUM IN BS8006 The BS8006 eqution fo W T do not meet the demnd of vetil equilibium. Thi i hown by tying to find n geement between the eqution fo vetil equilibium eqution (13), (17) nd BS8006-eqution (18): Full hing; >1.4(-) Vetil equilibium, eqution (13) nd (17) BS8006, eqution (18) D: W T? ( γ + p) 1.4γ ( ) : W T 0.5 ( γ + p)( + ) 5? 1.4γ ( )

6 EuoGeo4 Ppe numbe 315 A long the tem i not equl to zeo, thee eqution nnot be tified. n be evluted by ombining the eqution fo (14) nd the eqution (3) of Mton: C () In ombintion with the eqution (4) nd (5) fo C, thi give: End-being pile (3) Fition nd othe pile (4) i dependent on, nd nd i uully not equl to zeo. Eqution (13) nd (17) how tht the lod on the einfoement, lulted with vetil equilibium depend on the uhge lod p, while thi dependeny i not found in BS8006 (eqution (18) ombined with eqution (3) ee eqution ()). Thi mke obviou how the BS8006 eqution fo W T unde full hing w developed: Stting point w the D ppoh fo the eltion between W T nd p. The W T hould not be dependent on the uhge lod p, o the p w et to zeo. The height of the embnkment w epled by the height of the h, whih w hoen to be *(-) 1.4*(-), whih i in odne with tingul h with top ngle of 90 o.conequene of negleting the uhge lod p nd epling the embnkment with mximum height 1.4*(-) i tht vetil equilibium i no longe tified Ptil hing; 0.7(-) 1.4(-) Vetil equilibium, eqution (13) nd (17) BS8006, eqution (0) D: W T? ( γ + p) ( γ + p) : W T 0.5 ( γ + p)( + )? ( γ p) + Alo fo the ptil hing option, the D umption ppe to be the tting point fo the Bitih Stndd. Fo thi e, vetil equilibium i found! Fo the ppoh, the ptil hing e of BS8006 doe not tify the equiement of vetil equilibium: thi n be hown by tying to find geement between the eqution (17) nd (0): 0.5 ( + ) oweve, will lwy be mlle thn (othewie, the que pile p hould jut fit into eh othe!), no vetil equilibium i found nd BS8006 (the expeion on the ight) will lwy give lge vlue fo W T thn the ppoh fo the demnd of vetil equilibium (the expeion on the left). Impoving BS8006 To tify the equiement of vetil equilibium, to mke BS8006 fully, nd to limit the lod on the einfoement fo full-hing-iumtne (>1.4(-)), BS8006 hould ue the following expeion fo W T : (5) ptil hing : W T 0.5 ( γ + p)( + ) full hing : me but eple with 1.4( ) nd ume p 0 : W whee i given in eqution (). Thi give: T 0.7γ ( ) (6) WT WT ptil hing : ( γ + p), full hing : 1. 4γ ( ) (7) + + Now, fo full hing, p n be lulted fom eqution (9). Thee eqution gee with the bi umption of BS8006 nd the equiement of vetil equilibium nd the equiement tht the eqution hould be fully. Vn Eekelen et l, 008 how tht thi dpted BS8006 give lowe tenile tee fo ptil hing itution, loe to the tenile tee lulted with the Gemn EBGEO. Thi will lo be the e fo itution with full hing. They lo how tht the Gemn dft-stndd EBGEO give bette geement with the te ditibution in field tet nd theefoe it eem jutified to ue thee lowe tenile tee in deign. Tble 1 give ummy of thee ppohe fo ptil hing of BS8006. Fo full hing, the in the eqution fo WT hould be epled with 1.4(-) nd p 0. The diet lod on the pile p hould be dpted with eqution (9). 6

7 EuoGeo4 Ppe numbe 315 Tble 1. Summy fo ptil hing; ompion oiginl BS8006, intepettion of BS8006 nd dpted BS8006 BS8006 (Oiginl) BS8006 D BS8006 intepettion lod BS8006 Pmete ppoh on einfoement * fully ** Lod diviion kp σ totl lod on e * v γ + p kn σ v (γ + p) lod pt dietly on pile Vet. line-lod W T, due to p, on tip geotextile einfoe-ment between two djent pile p. lod pt ied by geoyntheti Tenile te T p in geotextile einfoement w E σ ' 1 E v σ ' σ ' w v v ( ) σ ' v Ste Redution Rtio SRR v σ ' kp C p ' σ ' kn w p kn/m W T (γ+p) *** W T 0.5 (γ+p)(+) WT kp ( γ + p) kn v ( γ + p) WT WT ( p) + + γ + + ( ) w ( ) w ( ( )( ) γ p) ( )( γ + p) ( )( γ + p) w + Clulted tenile te in geotextile einfoement W T ( ) 1 kn/m T p 1 + 6ε Clultion fto fo ompion with othe litetue eoue kn/kn kn/kn 1 E + (1-E) 1 ( ) E 1 E C kp/kp + ( ) E ( ) 1 E E + (1-E) 1 **** **** * in geement with Love & Millign (008), Stewt (005) nd Ruel & Piepoint (1997 ** dpted BS8006 *** fo ee eqution (): **** no vetil equilibium C E + (1-E) 1 Clultion exmple Tble give lultion exmple fo ptil hing. Vn Eekelen et l (008) how tht fo thi e the tenile tee lulted with the modified eqution fo BS8006 ppoh the pedition of EBGEO. CONCLUSIONS Bitih Stndd BS8006 how ome fundmentl inonitenie beue of: The oeffiient C peented in Mton eqution ditinguih hing on end-being pile (unyielding) nd on fition- o othe pile, while the umption of no uppot of oft oil i being mde. Thee umption do not gee with eh othe. BS8006 i billy D ppoh; thi ppe give eqution fo fully impovement. BS8006 mke the hoie to onide ot of h. Lod fom bove the h i not felt by the einfoement (full hing). Thi top lod i jut ignoed by putting it to zeo. Thi i implemented in wy tht the demnd of vetil equilibium i no longe met (fo full hing). 7

8 EuoGeo4 Ppe numbe 315 The tnition between full hing nd ptil hing i independent fom the oil popetie, lthough it i likely tht oil popetie do hve n influene. When the lod on the einfoement i lulted with ppoh, the demnd of vetil equilibium i no longe met, fo ll e. The lk of vetil equilibium i illutted with illuttive lultion. Fo thin embnkment (ptil hing), the D ppoh give vetil equilibium, howeve the ppoh give lod on the einfoement tht i 37% highe thn the totl lod. Thi give too fe deign. Fo the thik embnkment (full hing), the um of the lod on the pile nd the einfoement i lwy lowe thn the totl lod. Thi n give n unfe deign. Tble. Clultion exmple fo ptil hing; ompion oiginl BS8006, intepettion of BS8006 nd dpted BS8006, embnkment thikne 1.15 m, ente to ente ditne pile 1.7 m, pile p ide 0.7 m, end being pile, uhge lod p 0 kp, unit oil weight 18.6 kn/m 3. Pmete (Oiginl) BS8006 D ppoh BS8006 intepettion lod on einfoement oding to Love nd othe BS8006 fully totl lod on e * σ v kp 1.4 w tot kn 34.5 lod pt, dietly on pile p kp 77.9 w kn 5.5 line-lod on einfoement tip W T kn/m lod pt, ied by geoyntheti p kp w kn (lge thn totl lod) 9.0 tenile te einfoement (tin ε 0.04 i ontnt) T p kn/m tenile te einfoement (tiffne T p einfoement EA 1500 kn/m i ontnt) kn/m Clultion fto fo ompion with othe litetue eoue lod pile/totl lod E kn/kn 0.16 lod einfoement/totl lod 1-E kn/kn Ste Redution Rtio SRR kp/k P Aknowledgement: The membe of the CUR tk goup (Tk Goup woking on the Duth Stndd fo the deign of piled embnkment) nd Delft Clute e knowledged fo thei uppot. Coeponding utho: M Suznne J.M. vn Eekelen, Delte, P.O. Box 69, 61 NG Delft, Nethelnd. Tel: Emil: Suznne.vnEekelen@Delte.nl. REFERENCES Bitih Stndd, BS8006, 1995, Code of ptie fo Stengthened/einfoed oil nd othe fill, CUR 007- epot: "Eien n plmtytemen, plen en inventitie mt", n be downloded t publitie (in Duth) EBGEO: Empfehlung Bewehte Edköpe uf punkt- ode linienfömigen Tgglieden, juli 004, Entwuf EBGEO Kpitel 6.9. Deuthe Geellhft fü Geotehnik e.v. (DGGT). Fhektion Kunttoffe in de Geotehnik Abeitkei AK 5. Beehnung und Dimenionieung von Edköpen mit Bewehungen u Geokunttoffen. Eekelen, Suznne vn, Bezuijen, Adm nd Alexiew, Dimite (008), Piled embnkment in the Nethelnd, fullle tet, omping ye of meuement with deign lultion, to be publihed in the poeeding of EuoGeo4, numbe 64, Septembe 008. Jone, C.J.F.P., Lwon, C.R., Aye, D.J. 1990, Geotextile einfoed piled embnkment, Geotextile, Geomembne nd Relted Podut, Den oedt (ed.) 1990 Blkem, Rottedm, ISBN , pp Le ello, Btien, Renfoement p geoynthetique de embli u inluion igide, etude expeimentle en vie gndeu et nlye numeique, June 6th 007, pd thei, l univeite Genoble I, (in Fenh) Love, J. nd Millign, G. 003, Deign method fo blly einfoed pile-uppoted embnkment ove oft gound, Gound Engineeing, Mh 003 Ruell nd Piepoint 1997, An ement of deign method fo piled embnkment, Gound engineeing, Nov. 1997, pp Stewt, M.E. nd Filz, G. 005, Influene of Cly Compeibility on Geoyntheti Lod in Bidging Lye fo Column-Suppoted Embnkment, Poeeding of Geo-Fontie 005, USA, GSP 131 Contempoy Iue in Foundtion Engineeing 8

Chapter 19 Webassign Help Problems

Chapter 19 Webassign Help Problems Chapte 9 Webaign Help Poblem 4 5 6 7 8 9 0 Poblem 4: The pictue fo thi poblem i a bit mileading. They eally jut give you the pictue fo Pat b. So let fix that. Hee i the pictue fo Pat (a): Pat (a) imply