Evaluating total and effective stress parameters in soft clays from CPTu and DMT

Transcription

1 /7/ OVERVIEW Focus on CPTu and DMT in sof firm clays Esimae of uni weigh Evaluaing oal and effecive sress parameers in sof clays from CPTu and DMT Paul W. Mayne Georgia Insiue of Technology 5 Sepember Evaluae CAUC undrained shear srengh, s uc Review TH mehod for ' from CPTu Applicaion o Bohkennar clay and oher clays Simple SCE link beween CPTu and DMT Exended TH mehod for ' from DMT Deermine effecive cohesion inercep, c' CPTs from g chamber, cenrifuge, and in siu ess Twich esing and TH soluion SCPTù V s 5 f s DIRECT PUSH TECHOLOGY Piezocone Peneromeer crusal layer sof o firm clays f s = sleeve fricion u = porewaer pressure = cone resisance SDMTà V p V s flex p p Fla Dilaomeer p = expansion p = conac pressure CPT Chars for Soil Behavioral Type Soil Behavioral Type (SBT) inerpreaion of CPT soundings (Roberson, CGJ, 99, 99) Uses all 3 readings (, f s, u ) Define normalized piezocone parameers:. ormalized Tip Resisance: Q = ( )/ '. ormalized Sleeve Fricion (%): F = f s /( ) 3. ormalized Porewaer Pressure: B = (u u )/( ) f s u CPTU from Gulf of Mexico Clay Uni Weigh from CPT (Mayne & Peuchen ) Tip Resisance (MPa) Sleeve Fricion f s (kpa) Porewaer Pressure u (MPa) m f s u Piezocone Reading (kpa) Offshore GoG Sie X n = 7 m = /z = 33 k/m 3 u Deph below seafloor, z (m) f s y = 33.x 5.77 R² =.99 y = 3.9x R² =.993 y =.x 9.9 R² =.9975 y =.5x R² =.993 y =.37x R² =.9593 y =.7x R² =

2 /7/ Clay Uni Weigh from CPT Uni weigh of sof-firm clays from CPT (Mayne & Peuchen - ISC-) 3 Clays = GoG = + m / Onshore Offshore CPTUs in Bohkennar Sof Clay, Scoland (ash e al. 99 Geo; Powell & Lunne 5) (MPa) 99 5 f s (MPa)... u (MPa) Define CPT Parameer m for Uni Weigh in Sof Clays Cone Resisance, (MPa) Bohkennar Clay, UK 99 5 Uni Weigh, (k/m 3 ) Delf Pison m = /z m = 5 k/m 3 = w + m / u o Using CPT and Slope m for in Sof Firm Clays (Mayne and Peuchen ISC Pernambuco) CPT and Slope m for Uni Weigh in Sof Firm Clays Toal Uni Weigh, (k/m 3 ) Onshore and Offshore Clays Regression: n = 555 y =. x r =.7 S.E.Y. =.977 Unis: (k/m 3 ) m (k/m 3 ) (k/m ) =.3 ( ).7 ( +.5m ) W Ausralia India Bengal Gulf Mexico E Medierranean S Alanic Gulf Mexico Gulf Mexico 3 Gulf Guinea orh Sea orh Sea Gulf Mexico Caspian Sea S Alanic S Alanic 3 India Andaman Gulf Guinea Gulf Guinea 3 W Africa Gulf Guinea X Onsoy orway Burswood Ausralia Mexico Ciy Ariake Japan Bohkennar UK orhwesern Univ Recife Brazil Drammen orway Sarapui Brazil Lilla Mellosa Sweden Ska Edeby Sweden Bangkok Thailand Taipei K Louiseville Amhers Cone Resisance, (MPa) m = /z m = 5 k/m 3 Bohkennar Clay, UK Uni Weigh, (k/m 3 ) =f (, m ) Delf Pison =f (m )

3 /7/ ormalized Cone Resisance, Q n ine Zone Soil Classificaion (Roberson 99, 99, 9) CPT Soil Behavioral Type Char Sensiive Soils (Zone ) Siff clayey Sand Very (Zone ) Siff clays and sils (Zone 9). Fricion Raio, F r = f s /( - ) (%) CPTu resuls from sof-firm clays Mayne & Peuchen () Deph (meers) Sof Bohkennar Clay, UK (High e al. 3) Undrained Shear Srengh, s u (kpa) FV CKoUC DSS CKoUE Field Vane Triaxial Simple Triaxial Exension Shear Compression s uc Direc CPT evaluaion of peak s u in clays ne cone resisance: ne = s u = ne / k f s u excess porewaer pressure: u=u u s u = u/ u effecive cone resisance: eff = u s u = eff / ke remolded shear srengh s ur f s Direc CPT evaluaion of s u in sof firm clays (Mayne, Peuchen, & Baloukis, ISFOG 5) s u = ne / k SCE = Spherical Caviy Expansion (Vesic 97, 977) s uc undrained shear srengh in riaxial compression ne suc k = /3 [ln(i R ) + ] + / + k u suc u = /3 ln(i R ) u where I R = G/s u = rigidiy index Combining boh expressions: ne u suc k u u u u u = B k where B I R.93 B exp B ne 3

4 /7/ Excess Porewaer Pressure, u (KPa) CPTu Daabase in 3 Sof Firm Clays (Mayne and Peuchen, ISC Pernambuco ) 5 Onshore Clays 9 Offshore Clays Spherical Caviy Expansion (SCE) Ir = Ir = Ir = e Cone Resisance, ( ) (kpa) SCE Soluion for s uc from CPTu (Vesic 97, 977) s s uc uc where B ne ( B ) 3.9 u [(/ B ) ] 3.9 u u u ne Deermine he mean B over he profile as he slope from graph of u versus ne Individual B a each elevaion as u/ ne u (kpa) Bohkennar Sof Clay, UK CPTu (ash e al 99) CPTu (Powell & Lunne 5) y =.5x R² =.973 B = u/ ne y =.9x R² =.9539 ne (kpa) Deph (meers) Bohkennar Sof Clay: CAUC (High e al. 3) CPTu (Powell & Lunne, 5) CAUC Undrained Shear Srengh, s uc (kpa) ne suc ( B ) 3.9 u suc [(/ B ) ] 3.9 CAUC s uc Ave B =.5 Excess PWP, u (kpa) Gulf of Guinea (GoG 5) (GI UWA Repor) y =.5x R² =.99 B 3 ne cone resisance ne (kpa) Gulf of Guinea (GoG 5) (GI UWA Repor) Undrained s u (kpa) Lab CKoUC Lab DSS SCE ne SCE dela u B =.5

5 /7/ SCE Soluion for CPTu s uc a Burswood, WA (Schneider, Chung, Low 9) SCE Soluion for CPTu s u a Onsøy, orway (GI UWA Offshore Repor ) B =.9 B =.575 SCE Soluion for s uc from CPTu s s uc uc ne ( B ) 3.9 u [(/ B ) ] 3.9 s uc } u 3.9 Idenical s uc Profiles when B = u/ ne a each deph ' Deph (meers) Bohkennar Clay: CAUC and FV from High e al. (3) SCE wih individual B a each deph Undrained Shear Srengh, s u (kpa) FV CKoUC 99 Coninuous SCE 5 Coninuous SCE Bohkennar Clay ' u suc 3.9 SCE Soluion for CPTu s u a Ariake Clay, Japan (GI UWA Offshore Repor ) B =. 5

6 /7/ TH Mehod for Evaluaion 'from CPTu ne = ( -) ( ' + a') - u u = - = an (5 +'/) exp[( an'] u = an' (+an') a' = c' co' = aracion = angle of plasificaion B m c' co' B ' u u u ne u orwegian Insiue of Technology (TH); TU Janbu & Sennese (97) Sennese e al. (9) Sennese & Janbu (95) Sandven e al. (9) Sennese e al. (9) Sennese & Janbu (99) Sandven (99) Sandven & Wan (995) TH Mehod for CPTU Evaluaing ' in Sof Firm Clays Cone Resisance umber, Q Q an (5 ' / ) exp( an') an' ( an') M = Q = ( - )/ ' B = (u -u )/( - ) B = oes: c' = and = B Effecive Fricion Angle, ' (degrees) ne (kpa) Bohkennar Sof Clay, UK CPTu (ash e al 99) CPTu (Powell & Lunne 5) y = 5.75x R² =.97 y = 5.x R² =.95 m = Q = ne / ' 5 5 effecive sress, '(kpa) TH Effecive Sress Piezocone Peneraion Soluion Sandven & Wan (995), Sennese, Sandven, and Janbu (99) For c' = m = Q = ne / ' B = u/ ne = Q = 5.7 Cone Resisance umber, Q Porewaer Pressure Parameer B =.. Bohkennar..... '= 3 B = Effecive Fricion Angle, ' (degrees) Reconsiued Bohkennar Clay (Allman & Akinson 99) Deviaor Sress, (kpa) M c = sin'/(3 sin') slope M c =.37 ' = 3 Drained Compression Undrained Compression Drained Exension Undrained Exension M E = sin'/(3+sin') slope M E =.93 ' = 3 Triaxial '= 3 TH CPTu '= 3 Yield Surfaces (Leroueil & High 3) Range: 7 ' 3 Mean ' 3 aural Clays Mean Effecive Sress, p' (kpa)

7 /7/ MIT sress space an sin' c Inercep on ' s' space: a s '= c' cos' = ½( - 3 ) Yield Surface OC p fcn(k C ) Diaz-Rodriguez, Leroueil, and Aleman (99, JGE) s s' = ½( ' + 3 ') TH Effecive Cohesion Inercep c' Bohkennar ' = ( 3 ) kpa Effecive Cohesion Inercep c' Bohkennar Laval Pison Sherbrooke TH CPTu ( = ) ' = 3.7 c' =. kpa CSL ' = 3 c' = s' = ½( '+ 3 ') kpa Effecive cohesion inercep, c' TH mehod for CPTu: aracion inercep a' = c' co' from m plo Triaxial daa (Mayne & Sewar 9): c'. p ' Backanalyses of slope sabiliy case sudies (Mesri & Abdel Ghaffar 993):.3 < c'/ p ' <. Field plae load ess (drained & undrained) and riaxial ess (Sorensen & Okkels, 3): c' =. s u Approximae TH Soluion for 'from CPTu Theory: Q an (5 ' / ) exp( an ' ) an ' ( an ' ) Approx: ' 9.5 B. [ B + log Q ] Cone Resisance umber, Q c' = = ' (degrees) B Theory (dos) Approximaion (lines) B

8 /7/ Bohkennar Clay, Scoland aional Geoechnical Experimenaion Sie, orhwesern Universiy Effecive Fricion Angle, ' (degrees) Approximae TH Soluion Triaxial Tess TH CPTu 99 TH CPTu 5 Sof Clay a orhwesern Universiy CPTu and u (kpa) sand orhwesern Univ. (SP) aional Tes Sie Blodge Clay Deerfield Layer sof clay of Sudy Park Ridge Sof Clay a orhwesern Universiy CAUC and CAUE Triaxial Tess Sof Clay a orhwesern Universiy Q = ne / ' B = u/ ne ' (deg) Triaxials TH CPTu Manly Beach, Sydney, Ausralia

9 /7/ insiumanly.com.au Manly Beach Sydney, Ausralia SCE exus for CPTu DMT in Sof Clays SCE Soluions (Vesić 97, 977) Sof firm C LOC clays ( < OCR < ): CPTu DMT inerrelaionships: ne = /3 s u [ ln(i R ) + ] + / + CPTu{ u = /3 s u ln( I R ) = p u h = /3 s u [ln(i R ) + ] = p u Combining erms and rearranging: } DMT nedmt =.9 p.9 p u u DMT = (u u ) = p u CPTu u (kpa) 5 SCE exus for CPTu DMT in Sof Clays CPTu: u = u u DMT: u = p u DMT Euivalen u (kpa) 5 Amhers Anacosia Ariake Ballina Bohkennar Colebrook Road Eagle Farm Ford Design C Foynes Lila Mellosa orfolk orrkoping WU Onsoy PG Recife Sarapui Saro Rd /9 Saro Rd 7/ Ska Edeby Souh Glouceser Souh Porland Srandbacken Sundholmen Torp Valen h S BC : Line CPTu e Resisance, ne (kpa) 5 SCE exus for CPTu DMT in Sof Clays CPTu: ne = DMT: nedmt =.93p.93 p u DMT Euivalen ne (kpa) 5 Amhers Anacosia Ariake Ballina Bohkennar Colebrook Road Eagle Farm Ford Design C Foynes Lila Mellosa orfolk orrkoping WU Onsoy PG Recife Sarapui Saro Rd /9 Saro Rd 7/ Ska Edeby Souh Glouceser Souh Porland Srandbacken Sundholmen Torp Valen h S BC : Liine Deph (meers) DMT Sounding a Bohkennar (High e al. 3) p p Pressure (kpa) Clay Sil Sand. Maerial Index I D DMT Euivalen u (kpa) SCE exus for CPTu DMT in Sof Clays Bohkennar Clay 5 3 u DMT = p u y =.53x R² =.959 B DMT =.5 nedmt =.93p.93 p u DMT euivalen ne (kpa) 9

10 /7/ DMT Euivalen ne (kpa) SCE exus for CPTu DMT in Sof Clays Bohkennar Clay nedmt =.93p.93 p u y = 5.7x R² =.93 Q DMT = Effecive sress, ' (kpa) Resisance umber, Q DMT TH DMT Mehod for 'in Sof Firm Clays Bohkennar Clay Q DMT = 5. B DMT =.5 B DMT = '= 33 oes: c' = = Effecive Fricion Angle, ' (degrees) Deviaor Sress, (kpa) Bohkennar Clay (Allman & Akinson 99) M c = sin'/(3 sin') slope M c =.37 ' = 3 Drained Compression Undrained Compression Drained Exension Undrained Exension M E = sin'/(3+sin') slope M E =.93 ' = Mean Effecive Sress, p' (kpa) Triaxial '= 3 TH DMT '= 33 Deph (meers) Euivalen TH mehod for DMT in Sof Clays 'from Q DMT and B DMT Bohkennar Clay TH Triaxials Fricion Angle, ' s uc =u DMT / u CAUC k = du = s uc = nedmt / k Srengh, s u (kpa) Anacosia aval Air Saion, Washingon, DC Hangar for Marine One DMTs for Evaluaion of Driven PSC Piles Anacosia AS, Washingon DC Whie House Washingon Monumen US Capiol Penagon Poomac River Hangar for Marine One Anacosia AS

11 /7/ DMT a Anacosia AS, Washingon, DC DMT Sounding CFD Sof Poomac River Clay DMT Euivalen ne (kpa) Anacosia AS, Washingon, DC DMT Euivalen Resisance umber: m =.5 DMT Euivalen Porewaer Pressure: B =.9 y =.99x R² =.99 3 Effecive Sress, ' (kpa) DMT Euivalen u (kpa) y =.97x R² =.975 m = Q =.5 B =.9 DMT euivalen ne (kpa) Effecive Sress Peneraion for Fla Dilaomeer Adaped afer TH Soluion by Sennese, Sandven, and Janbu (99) Porewaer Pressure Parameer B =. Anacosia AS. Washingon DC..... Q DMT =.5 Cone Resisance umber, m '= Effecive Fricion Angle, ' (degrees) B =.9 Deviaor (kpa) Anacosia aval Air Saion, Washingon, DC CIUC Triaxial Tess: '= 35.3 TH CPTu Evaluaion: '= Anacosia AS, Washingon, DC T T T T3 T T Mean Effecive p' (kpa) Deviaor (kpa) Anacosia AS, Washingon, DC M c =.3 M c = sin'/(3 sin') c' = kpa '= Mean Effecive p' (kpa) DMT Euivalen Q and B for sof firm clays m B DMT Q DMT.93 p.93 p u ' p u.93 p.93 p u TH Approximaion: ' 9.5 B. [ B + log Q] Anacosia AS, Washingon, DC Lab Triaxial ' =35. DMT TH

12 /7/ Calibraion of TH Mehod for ' Resuls from mini cones in g chamber ess (mosly kaolin or mixes) Cenrifuge ess wih mini piezocones Documened field es sies wih full size peneromeers and companion riaxials ess Documened sies wih DMTs Some uesions: which '? (peak, maximum obliuiy, criical sae ' cs ) Wha value of = angle of plasificaion? Calibraion of TH Mehod for g Clay Chamber Tess (Ouyang, Mayne, & Sharp, GeoVancouver ) Lab Measured Triaxial '(deg) Regression n= ; r =.3 ' TX =.9' CPTu TH Evaluaed ' from CPTu (deg) Bohkennar Parille clay Gaul Clay Speswhie Speswhie Cornell clay K 5 mix Speswhie 3 K mix K 33 mix K kaolin K 5 mix Preliminary Calibraion of TH Mehod for Field Sies (Ouyang, 7) CPTu Twich Tesing and TH 'Soluion (DeJong e al. ISC Pernambuco) Peneraion Rae, v (cm/s).. ormalizedvelociy V = v d/c vh = 3 Sandard Rae = cm/s Clays Sils and Mixed Soils Sands Coefficien of consolidaion, c vh (cm /s) Rae effecs CPTu Twich Tesing ormalized Velociy: V = v d/c v where v = probe velociy, d = probe diameer, and c v = coefficien of consolidaion. DeJong and Randolph (): Q Q B ref B ref ( Qdrained / Q ( V / V ref 5 ( V / V ) c ) 5 ) c Q = ( - )/' Cenrifuge CPTu Twich Tesing in Kaolin (Schneider 7) fully drained parially drained fully undrained... ormalized Velociy, V = v d/c v

13 /7/ B = u /( - ) Cenrifuge CPTu Twich Tesing in Kaolin (Schneider 7) fully drained parially drained fully undrained... Cenrifuge CPTu Twich Tesing in Kaolin (Schneider 7) Velociy (mm/s) o 3.3 o.3. ormalized Velociy, V = v d/c v Cone Resisance umber, Q CPTu Twich Tesing and TH 'Soluion Cenrifuge CPTUs in Kaolin Undrained Parially Drained Drained '= from lab srengh ess '= 35 3 '= 3 ypical of kaolinie Porewaer Pressure Parameer, B Many Thanks 3