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International Conference on Case Histories in (1998) - Fourth International Conference on Geotechnical Engineering Case Histories in Geotechnical Engineering
11 Mar 1998, 1:30 pm - 4:00 pm
Study on Mechanism of Caisson Type Sea Wall Movement During Earthquakes
Masayuki Sato Tokyo Electric Power Services Co., Ltd., Tokyo, Japan
Hiroyuki Watanabe Saitama University, Urawa, Saitama, Japan
Satoshi Katayama Saitama University, Urawa, Saitama, Japan
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Recommended Citation Sato, Masayuki; Watanabe, Hiroyuki; and Katayama, Satoshi, "Study on Mechanism of Caisson Type Sea Wall Movement During Earthquakes" (1998). International Conference on Case Histories in Geotechnical Engineering. 12. https://scholarsmine.mst.edu/icchge/4icchge/4icchge-session03/12
This Article - Conference proceedings is brought to you for free and open access by Scholars' Mine. It has been accepted for inclusion in International Conference on Case Histories in Geotechnical Engineering by an authorized administrator of Scholars' Mine. This work is protected by U. S. Copyright Law. Unauthorized use including reproduction for redistribution requires the permission of the copyright holder. For more information, please contact [email protected]. 604 Proceedings: Fourth International Conference on Case Histories in Geotechnical Engineering, St. Louis, Missouri, March 9-12, 1998,
Study on Mechanism of Caisson Type Sea Wall Movement During Earthquakes
Mnsaruki Sato Hiroyuki Watanabe Satoshi Katayama Paper No .3 18 Tokyo Electric Power Sen· ices Co .. Ltd Saitam:1 UniYcrsitv Sait:nna UniYcrsitv TokYo ll (l,Japan Un.ma. Saitama :ns. Japan Urawa. Saitama 338. Japan
ABSTRACT
Model vibration tests under gravity and centrifuge model ribration tests in 50G were performed to investigate the behavior of caisson type sea mill \\ ith reclaimed gronnd below and behind the caisson. In the tests. sliding of caisson occurred only during excitation, which indicates that it is impossible to predict the disphlccmcnt of caisson and the deformation of back-fill ground without taking account of both inertia force of caisson and d~ namic earth pressure_ As for the dynamic earth pressure acts on the caisson. it W KEYWORDS caisson type sea waiL reclaimed ground. liquefaction. excess pore \Yater pressnre. dynamic earth pressure. large ground dcfornwtion INTRODUCTION research for the above purpose, arc performed in order to examine the mechanism of movement of caisson type sea wall From t.hn past damag-e of harbor strudurPs. many with reclaimed ground behind it. Besides, centrifuge model eases of large ground deformation sw~h as latt'ral flow vibration tests 111 SOG \-Vere performed to investigate the and snttl(~ment dw: to liquefact.ion aeeompcmying- a behavior of caisson and reclaimed ground just below and larg(~ displaeement. of cnisson toward S(~11 sidl~ wr.rr~ behind the caisson under the same confining pressure as actual found. In recent earthquakes. particularly in Kushiro-oki structure. earthquake (!993 ), Hokkaido Nansci-uki earthquake (!994) and Hyogo-kcn Nambu earthquake (I ')95). such kinds of damages were obscr\'cd in \'arious seaside places. In their MATERIAL FOR MODEL neighborhoods large accelerations or 400gal to 500gal \-vcrc obscrYcd. Howe\·er. in the design of such structures as caisson Gcncrall~-, in shaking table tests, liqucftlction docs not last type sea walls. only the e\·aluation weather the sliding or long hccause the model is so small that the excess pore water caisson occurs or not is performed by applying around 0.1 to pressure disperses too early. Besides, the behavior of ground 0.2 of seismic coc!T!cient. and the c\·;lluation on the amount or model dnring excitatiou becomes difTcrcnt from that of real caisson's sliding is scarcely performed. !!round because of extreme low confining pressure (Towhata et al. I ')!)5). Taking account of the above facts. the ground model From now OIL 111 the aseismic design for airpol1 I;Jcilitics. made of extreme lose sand. for example relativity density less pmycr station facilities on reclaimed islands as \\ell as general than 0 '~'0. is occasionally prepared so that it can shows harbor stmcturcs. the CY Fourth International Conference on Case Histories in Geotechnical Engineering Missouri University of Science and Technology http://ICCHGE1984-2013.mst.edu 605 0.4 -~ 1.E-01 --+- torstonal ~ 1.E-02 0 -o-- triaxial :.0 -~ 0.3 IV l ~ Q) '\" p~ ,... G 0:::: ~- l .E-03 (I) ~ E---Q) 0 (I) h.. - E> Q) ~ a. ~~--- .. (I) \ ...... ~ 0.2 1- - 1- 0% -- .... , l.E-04 '"""'"! C/) o E roo ..... 0 0 t-- b .... . I.._. ~--- l .E-05 -...;;;:: 0 '(3 ·------()>- 0 . 1 --1-f- f.:-. 0 ~:> lc - lE Q) l.E-06 -- - f---- I 0 - ~ -- ~i () ---- 0.0 I l.E-07 10 100 1000 0 20 40 60 80 100 Number of Cycle, N, DA=5% Fines Content(%) Fig.-1 Uquefaction Strength of DL-clay Mixture Sand Fig.-2 Coefficient of Permeability ofDL-clay Mixture Sand ? 100 '-" Cl) 1 .....~ 80 c: o~~l:JII : i It~ Cl) ·t ...0 Experiment L Q) 60 - ·- ~.' materials {; ~- - - 1 a. .' (DL -clay 20%) ' 40 --1-1- F;f .' -Toyoura Cl) V¥'!,.-Sand ~ 20 r (I) (I) a.IV ...... 0 0 .001 0.01 0.1 Grain Size (mm) 0'""'""' 0. 2mm Fig-3 Grain Srze Distributwn of'lb_voura Sand, DL-clay and Photo-/ Microstructure ofDL-clay (20%) Mixture ,)'and DL-clay ( 10%) Mrxture Sand Model Dcscript ion nm:ed mth DL-clay indicates extremely lower liquefaction strength (F1g. -I) and shows more remarkable tendency of A rigid vessel made of steel plates ha\'ing its inner d11nension. negati\c dllatanC) than those of the specimen made of 100% 200 em long. 65 em "ide, and 45 em high. "as fi '\ed on the Toyoura sand '' ith the sa me relati\'C density as that of DL-clay shaking table. Inside the \'CSsel. the model consisting of a mixed saud specimen. Besides. the specimen made of the DL mortar block, front water, water saturated base and backfill soil clay m1xture sand indicates low permeability too (Fig.-2). was installed as shown in Fig.-4. For simplicity, mbblc mound and mbble back-filling of actual structure \verc not considered. DL cia~ l'i non-plastic silt "hich has the grain size distribution and the ''ater lc\'el \\as set at ground surface. sh0\\11 111 fig. -3 The gnlin site distnbutions of Toyoura sand and the nt1:xture of 80% To)Otlra sand a nd 20% DL cl Fourth International Conference on Case Histories in Geotechnical Engineering of the model arc shown in fig.-4 Missouri University of Science and Technology http://ICCHGE1984-2013.mst.edu ( ) 606 Direction of Shaking D Ao.:celerometer (horizontal) 1!1! Ac..:elcromctcr (vertical) [). Pore Pre~sure Transducer 0 Em1h Pressure Transducer ~ ~ IYDT " ~ lit ~ Gap Sen.~or l ' 0 1 \ t t .'i' ------+ fr---+------~;~) .. __ !," --- i\ Cuisson ' ',)8 Bm.:k fi 11 Sand 30 OA-- I .'1\8 ' OA _\t --·-- ' l I Rigid Vessel '' (a) Alodei-A Unit : em r->----"-~ ~.'c'c_j-c~~~~~-_[]__n_I\~·~·L__---Q-----,,r-, --Q------'b-u--;-----] - -,1, Q------Qa---'1,~9 -- j,______- :10 Caisson 8 b. J". - . A ' 8 Backfill Sand ' ------DAA,!;"-;c------, __ ------"''=---- f----)\''-'___ _L ____ _j • >fj ·-----6~-- ~~-- fl__ ------• !', ',' 1 () m G Rigid Vessel n (b) Modei-B Unit : em Fig-4 }o.dodel Conflgra!ion Table-] Experimental Cases Experimental Case Material of Model Expected Level of lnout Motion Rccraimcd Ground 50eal !50eal 400eal Model-A DL-clav Mixture Sand AF-50 AF-150 AF-400 DL-day Mixture Sand - - 131'-400 Modd-13 Sand - - BS-400 150gal and +OOgal of input Fourth International Conference on Case Histories in Geotechnical Engineering Missouri University of Science and Technology http://ICCHGE1984-2013.mst.edu 607 .Sand .Smu.! Acceleration at Base ------DL-clay Mixture Sand DL-r:l E'l Horizontal Displacement of Caisson E 8 0 2'··-'--' 4 ---t--· J·lg-5 Inpul Accc!erarion and Pure 1f(Ifer Pressure l'ig-6 Input .-Jcrelerarion and Iforizonta{ Di.\placemenf (fCai.•;s(m Jest Rcs!!lts tlte inclination of each loop in the figure can explain the ratio of earth pressure Ycrsus unit response acceleration of caisson. Fig.-5 sho"s. the horizontal input acceleration recorded ;1~ the base of the yessel ;Hu..l c.xccss. pore \Yater pressure recorded at According to this figure. as the excess pore water pressure of point A indicated in Fig.-4 during the tests of Model-B. flg.-() AF-50 hardly generates due to low input motion, so that, the shows the horimntal input accdcratton and the hori.rontal loop traces around the starting point. and its inclination displacement at the top of the cai~~on in the same case as f Recorded input acceleration of BF-400 \vas considerably· On the other hand, in AF-150 and AF-400, because of high smaller th;m that of HS--WO as found in fig.-5. because the input motion, the loops gradually shift upward due to initial coutrol of shaking table \\ilS not so proper in Df-..J-00. In spite buildup of excess pore w As for the behavior of caisson in the tests of BF-400 and BS- CENTRIFUGE MODEL VIBRATION TESTS 400. in spite of the ground just below caisson \ras thick and large input motion "as applied. sliding of caisson occurred Model !Jcscriplion only within excitation. as shcnrn in Fig.-6. A rigid vessel made of aluminum plates having its inner Fig.-7 shcnrs the relationships bet\\ccn the response dimension. 110 em long, ..J-0 em \vide, and 30 em high, was accelerations of caisson Fourth International Conference on Case Histories in Geotechnical Engineering Missouri University of Science and Technology http://ICCHGE1984-2013.mst.edu 608 EP-t(AF-150) EP-1(AF-400) 3 15 I 30 NE C' 10 E 20 0 0 ' 5 'i. 10 ","c ,e . 0 . 0 .0 "e c Q_ -5 Q -10 £ £ ~ -10 -20 w• w~ -3 -15 -30 -60 -40 -20 0 20 40 60 -300 -200 -100 0 100 200 300 -600 -400 -200 0 200 400 600 Acceleration of Caisson (gal) Acceleration of Caisson (gal) Acceleration of Caisson (gal) EP-2(AF50) EP-2(AF-150) EP-2(AF-400) 3 15 30 "E 2 N 20 0 E 'ID ' ,o -c--~-~l "" 10 ~, "'e . 0 , 0 •e .• Q_ -1 e Q_ -10 £ £ ~ -2 t -20 w• w• --- --+---t---+--+---j -3 -15 -30 -60 -40 -20 0 20 40 60 ··300 -200 -100 0 100 200 300 -600 -400 -200 0 200 400 600 Acceleration of Caisson (gal) AcGelcration of Caisson (gal) Acceleration ofgCaisson (gal) EP-3(AF-50) EP-3(AF-150) EP-3(AF-400) 15 30 1- ' ---,~ 10 20 ___ I ~0 -; ---+_j: io 10 - ~ e 0 0 0 -f3: ~. .' .• 5 0:" -10 - £ £ t -10 'fii -20 i w w -3 -15 -30 I -60 -40 -20 0 20 40 60 -300 -200 -1 00 0 100 200 300 -600 -400 -200 0 200 400 600 Acceleration of Cai,.;son (gal) Acceleration of Caisson (gal) Acceleration of Caisson (gal) Fig.-7 Relationship 8elm:cn Accelerations of Caisson and /~·arth pressures Act on Caisson (}.lode I-A) ground surface, which \Yerc similar to Fourth International Conference on Case Histories in Geotechnical Engineering Missouri University of Science and Technology http://ICCHGE1984-2013.mst.edu 609 !-- i k j.... ,!.... Notes ~ o Pore Pressure 0 co Caisson co oo ~ Transducer Backfill Soil \Vater 0 ~ co co co - o Accelerometer 0 m • • • 0 N • Eruth Pressure Transducer 0 0 c oWp-4 OWp-3 oo Wp-2 0 oWp-1 1- Wp-6 Wp-5 f Displasemcnt ~ ~ Sensor Direction of Shaking (Unit em) Fig.-8 ,\!ode! C01~{iguralion (\!odei-C) l'ahle-] l~'xperimcntal Cases (~(Centr(fuge Tests Matc11al or Exp.::rimcntul Ca:)e ------Model Rccraimed DL-cl11\ Mixture Sand CF-20G Modei-C --- Sand CS-20G condition as the model of s~md Fourth International Conference on Case Histories in Geotechnical Engineering Missouri University of Science and Technology http://ICCHGE1984-2013.mst.edu 610 30 30 20 10 ('3 0 0 -10 -20 F1M~ill~~, -30 -30 0 05 01 0>5 0 2 0.25 0 3 Sec 0 0.05 01 0 I 5 02 0.25 0.3 Sec 30 30 Horizontal Acceleration of Caisson Horizontal Acceleration of Caisson 20 20 10 10 0 0 0 0 v'f'!VWJI/IP~~vv -10 NdJ~~W~\~\~~~~~ -10 -20 -20 -30 -30 0 05 0 I 0 15 0.2 0.25 0 J Sec 0.05 0.1 0.15 02 0.25 0.3 Sec 15 15 Horizontal Displacement of Caisson Horizontal Displacem~~~f Caisson 10 10 E 0 E ~ E E 0 -5 -5 -10 -10 -15 -15 0 0 05 01 0 15 02 025 0_3 Sac 0.05 0.1 0 15 0.2 0.25 0.3 s~c (a) ( 'a.\c 1!/( F-]Q(j (})L-day .\fixture ,Hodel) (hJ Case (?fC.\'-20(1 (.\and ,\/oc/1!/j Flg.-9 Input .\Jut ion am/ Re.'>ponsc ofCais.vm ,-\lode/ "' 1.0 "'E 1 o g 05 ~ 05 Wp-1 ~ 00 ~ 00 -0.5 -0.5 " 10 •' _,., 1/ \/l- V' " 10 ' 10 ~ 0 5 .... -~--~._-/'------~ 0.5 __ ./ Wp-·3 ~00 ~0.0 -a> -0.5 0.30 000 015 020 [1_30 000 o.os "' 0.20 025 '" Time (s,cl Time {sac) Fig.-10 J..~n.'CSs Pore fi(Her J>rcssure m Ca.<>e oJCF-20G (JJL-c!ay 1\fixlure ,\lor/e)/ As for the bch;-l\'ior of caissOIL sliding of caissons occur only the dynamic earth pressure acts so as to restrain the rnoYement during e.xcitation_ In the case \\]Jere the grmmdjust below the of caisson and the excess pore \Yater pressure hardly occurs. caisson is more thick. or in the case when the high level of On the other hand. \rhen the input acceleration is large enough excitation 1s applied. the possibilit~ of post-excitation to cause liqucniction, dynamic earth pressure acts rather so as displacements of caisson might Hot be denied. Howcycr, it to promote the mmTmcnt of caisson. Couscqucntly, eyen if in must be impossible to predict the displacements of caisson and the same ground. it may be concluded that a tendency of the the deformation ofback·nll ground unless both inertia force of inDucncc of the back·fill on the caisson changes depending caisson and dynamic earth pressure arc taken account upon the lc\"el of input acceleration and the degree of e:-.::cess pore 'rater pressure. From the analysis on dynamic earth pressure obscrYcd 111 experiments, it is found that \Yhen input acceleration is small. Fourth International Conference on Case Histories in Geotechnical Engineering Missouri University of Science and Technology http://ICCHGE1984-2013.mst.edu 611 P-1 (CF-20G) 03 "Eo 02f--t---i- 1> 1::U~~~u~ ..)£ 0.1 t e 0 0 0 0 .• .• J: -0.1 J: -0 1 ~ ~ ~ -0.? ~ -0_2 f--1--f- w ---=~-- t-~ w -0.3 -0 :l -15 -10 -5 0 5 10 15 -15 -10 -5 0 5 10 15 !l.t:celeration of Caisson (G) Anneleration of Caisson (G) P-2(CF-20G) 0.3 0.3 NE 0.? "'E 0.2 0 0 11~ 0.1 j 0.1 -- ~ 0 0 ~ 0 .• ~ J: -0.1 J: -0.1 ~ -;; ~ -0.2 "' -0.2 w w __ j -0 3 '--~-- -'---- -0.3 -15 -10 -5 0 5 10 15 -15 -10 -5 0 5 10 15 Acceler11tion of Caisson (G) Acceleration of C11isson (G) P-3(CS-20G) 0.5 1 0.5 "E 0.4 ~ 0.4 0 ~-:! 0.3 ~ 0.3 e0 0 2 :J" 0.2 .• . J 0.1 J: 0.1 -;; . 0 0 w -Q_I -0.1 -15 -10 -5 0 5 10 15 -15 -10 -5 0 5 10 15 Acceleration of Caisson (G) Acceleration of Caisson (G) Ftg.- I I Re/atirmsl!ip Bctln'elt .·lccderalions o/Caisson and /~·arlit pressures /I cl m1 Caisson (,\fodci-C) ACKNOWLEDGMENT REFc.RENCES This study w·as funded by the In-house Technical Dcyclopmcnt Sa1o, :VL Oda, M .. KannlliL H. and Ozcki, K. [1997[ Program of 19~5 - 1~~(J Fiscal '{car or TEPSCO. The model "funda111cutal Study Oll The EITcct of fines on Liquefaction \·ibration tests under gr;n-it~ and centrifuge tests were Strength of Reclaimed Ground". J. Gcotcch. Eng., JSCE, performed at S;titama UniYcrsity and at the laboratory of No.56!/lll-38, Pi' 271-282. Takenaka Cmvora1ion rcspcctiyeJ~-. The authors wish to express their sincere gratitude to the staff of Sait;lln Fourth International Conference on Case Histories in Geotechnical Engineering Missouri University of Science and Technology http://ICCHGE1984-2013.mst.edu