ffl Bien^bci

(1)

DI£N DAN KHOA HOC

TU DONG HOA TINH TOAN TOI UU HINH DANG

• • •

CONG TRiNH THUY KICH THUCJC ^LCJN DANG

•

KHOI TRON XOAY BANG PHJClNG PHAP PHAN TLf BIEN THEO QUAN DIEM DO TIN CAY

* PGS.TS. DO VAN DE Vien Cang-Ky thugt Hdng hdi TrUdng E>gi hoc Xdy dUng 1. Tdng quan ve cdc loai cdng trinh thuy

kich thffdc ldn (CTTKTL)

CTTKTL Id mdt trong nhffng ke't ca'u kinh te'ffng dung cho cdng trinh be'n cang nffdc sau ndi rieng va cac cdng trinh bien trpng lffc ndi chung, vi du nhff: be'n tru d'ng dffdng kinh ldn, dang cff vay d, ddn khoan bien, cdng trinh ben trpng lffc, cdng trinh be'n nd'i...Cdc dang ke't ca'u ndy cd cdc ffu diem sau:

- Cd dp dn dinh cao (tff dn dinh bdng trpng Iffdng ban than);

- Cd tdc dung giam cffdng dp dp lffc sdng;

- Hinh dang, kich thffdc khd'i ldn, cd kha ndng hinh thdnh tuye'n ben hay de chan sdng Iffdng dd'i ddi vdi cdc phan doan rieng;

- Dd'i vdi cdc khd'i ddt chim vdo da't nen cd the giam khd'i Iffdng nao vet hd'mdng, thi edng ldp dem, khdng nhffng giam dffcJc kinh phi xay dffng ma cdn giam thdi gian thi cdng.

- CTTKTL thffdng 1dm bang be tdng hodc BTCT cd kha ndng chd'ng xam thffc td't, tudi thp cdng trinh cao.

1.1. Cong trinh Men trgng lUc

Tinh de'n nay tren the gidi da cd hdn 40 cdng trinh bien trpng lffc be tdng dffdc xay dffng tren bien de khai thdc dau khi, nhff cdc viing bien Hd lan, Brazil, bien Bac, Vinh Mexico, bien Baren, d Oxtraylia, d Inddnezia... Cdng cudc khai thdc bien va dai dffdng ngdy cang dffcJc chu y phat trien. Cac the he ddn khoan bien ngay cdng dffcJc hodn

thien vd vffdn ra xa bd hdn. Qua nhieu cudc hdi thao da khing dinh Viet Nam ed dii dieu kieji de xay dffng loai cdng trinh bien nay.

1.2. Ben tru dng dUdng kinh ldn

Ben tru d'ng dffdng kinh ldn da dffdc sff dung rat nhieu d cdc nffdc nhff Nga, Nhat Ban... Ndm 1965, d Klaiped (Nga) da xay dffng ben tru d'ng dffdng kinh ldn cd ban giam tai (HTnh 2). Tru d'ng cd trpng Iffdng 83,6T ddt vdo hd' mdng dffdc ddo sau bang tdu cudc. Tff ndm 1969 - 1977, d cang Sevastopol da dffa vdo khai thdc 700m be^n lam b i n g cdc d'ng dffdng kinh Idn lap ghep. Cae d'ng ed dffdng kinh 10,5m ghep tff 10 ta'm be tdng cd't th^p phang [2].

3.75 +2.0

•v7

0.0

-8.0 -10.0 "

1 \

0.14

^ -

f ', .,. . k»j

" • ; • • • ' • . : . ' . - • : • • • • ;

•••• • • - • ' • . - . . ! " - ' • • - . ' • • • •

• ' • - o - s . : • : ; • ' . - • '

i.';^:.J^j:-^,_

" • — ^ ^ ^ _ ^

P ' , ,;,• •,• '1

: 3.35 ::i

' • ' * : • • • V

" . . " . - • " .

^ " ^

Hinh 2. Ben tru d'ng dffdng kinh ldn cd ban giam tai

Tai Viet Nam, tru d'ng be tdng cd't thep dffdc xay dffng nhieu d cdc cdng trinh cau dffdng bd, trong xay dffng cang mdi chi thie't

66

Sd thdng 3 ndm 2010

(2)

Bien^d

DI£N DAN KHOA HOC ke cho ben cang, cdn vdi de chan sdng chffa

manh dan dp dung, song ciing hffa hen nhieu dieu td't Idnh. Ve mat thi cdng tru dffdng kinh ldn thi Viet Nam da cd nhieu kinh nghiem trong xay dffng cau bang sff hd trd ciia can cau cd sffc nang ldn.

y<

•:-:-:-:-:-:-:

/ ^ //^ yWi

•

/^ /n. />

'-••i'">-.'.i ; • ; < ; . - : . - , C "

''.y'-':-.^:..

k\ / > ^ /^

+5.0

0.0

0.3

-12.5

/^^ /^^ /r^ \- ^12.5

X

Hinh 3. De chan sdng bang tru d'ng BTCT

D= 12,5m d cang Khanlskholm Tai cdc nffdc tren the'gidi, ke't ca'u de chan sdng bdng tru d'ng du'dng kinh ldn lu'dng dd'i phd bien. Tai cdc cang Kiel, Hambourg, Bremen thupc CHLB Dffc dd sff dung cac tru be tdng cd't thep ffng sua't trffdc 1dm de chan sdng. Tai Dan Mach cung da xay dffng mdt luyen de chan sdng bang tru d'ng D=12,5m d cang bien Khanlskholm (HTnh 3), d Kdbe - Nhat Ban (Hinh 4).

O.G xz__

•fl.C V

-12,5 2.!

7^^ '

_J

M O

vi

1

(

1

0-

15 8

'

01

'

chuyen, ha cpc cho de'n cdng tdc hodn thien.

Ngodi ra, ludi thp cdng trinh cao cung nhff thich nghi dffdc vdi dp xam thffc manh ciia nffdc bien ciing Id mdt ffu the' khien cho kdt ca'u nay dffdc sff dung nhieu.

1.3. Cit dong vdy 6

Cff ddng vay d dffdc sff dung nhieu trong cdng trinh de chin sdng hdn. Cff cd the la cff thep hodc cff be tdng cd't thep nhffng cff thep dffdc sff dung phd bie'n hdn. Cff dffdc ddng vay lai thdnh cac d cd cdc hinh dang khdc nhau nhff iron, bdt giac, luc ldng... Cff ddng vay d dffdc sff dung nhieu d cac nffdc cd cdng nghe thep phdt trien nhff Nhat Ban, Tay Au, Hoa Ky. De chan sdng d cang cd Funagata (Nhat Ban) sff dung tff ndm 1927, diing cff Larsen loai I vd loai II ddng thang dffng cdeh nhau 5m.Tai cang Larvik (Na Uy) cd de chan sdng bang cff thep Larsen cd chieu rpng dinh de 31,5m [2].

A - A

Hinh 4. De chdn sdng bang tru d'ng BTCT

D=15,8m d Kobe-Nhat Ban

Tdm lai, tru d'ng dffdng kinh ldn md ra nhieu trien vpng cho cdng trinh de chan sdng, song cung ddi hdi nhieu cdng nghe, thiet bi hien dai phuc vu cho cdc khau che tao, van Sd thdng 3 ndm 2010

BfcANG

Hinh 5. Ca'u tao de chan sdng bang cff thep vay d

Tuy cff thep ddng vay d cd bi mdi trffdng bien an mdn song thdi gian thi cdng nhanh vd giam du'pc nhieu cdng tdc lan nen ket ca'u ndy ciing dffdc sff dung nhieu. Tai Viet Nam dd xay dffng dffdc 11 ben tffdng cff d cang Hai Phdng nen viec thi cdng cff vay d cung khdng gap nhieu khd khdn.

2. Nhffng bSt cap

- Cdc loai ket ca'u tru d'ng dffdng kinh ldn, cff vay d, dan khoan bien trpng lffc... mac dii cd hieu qua kinh le - ky thuat cao, song hodn todn mdi me d Viet Nam. VI vay viec nghien

67

(3)

QM B i e r i ^ d DitN

DAN KHOA HOC cffu chiing dc dp dung trong dieu kien Vict

Nam la rat can thie't.

- Cac loai hinh kcl ca'u CTTKTL khdng chi ddi hdi cdng nghe thi cdng cao, thie't bi hien dai ma con phffc tap ca ve mat thie't ke', cdn khau linh loan rat khd khan theo phffdng phdp giai lich, thffdng phai di theo dffdng Id'i md hinh loan. Chinh vi vay can phai ddt ra van de nghien cffu cdc md hinh sc)' bien dai de giai Iren may linh cho cac chiing loai bai loan nay.

- Trong cac loai bai todn dat ra dd'i vdi CTTKTL thi bai lodn xdc dinh tai trpng sdng len loai cdng trinh ndy Id vd cung quan trpng.

Cac CTTKTL chiu nhieu loai lac dpng cua mdi trffdng trong do lac dpng ciia sdng Id trdi hdn ca. Dac biet la cdc cdng trinh dat d ngodi bien va ven bien thi lac dpng ciia sdng len cdng trinh chie'm khoang 9iW( la'l ca cdc loai tdc dc)ng ciia mdi trffdng len cdng trinh. Song cho de'n thdi diem hien nay, d Vict Nam cd rat It lai lieu, iham chi la cung chffa cd quy trinh quy pham hffdng dan vc van de linh lodn lai trpng sdng tdc dung len CTTKTL;

- Hien nay, lieu chuan thidl ke'cong trinh ben cang bidn ciia Vict Nam dang qui dinh sff

dung tieu chua'n 22 TCN-222-95 de tinh todn xdc dinh tai trpng do sdng tdc ddng len cdng trinh lhuy[5]. Tieu chua'n ndy chi de cap de'n tinh loan lai trpng sdng tdc dung len vat can cue bd thang dffng vdi D < 0,4>. (trong dd D Id kich thffdc ngang ddc trffng eiia tiet dien, X la chieu ddi sdng) diing chung cho ca ket ca'u cpc vd iru cd xet de'n he sd'lan can.

3. Dat vS'n dc nghien cffu

"Vdi dien tich xung quanhrmgt ifdt ket cdu CITKTL (dien tich be mat ke't cd'u tie'p gidp vdi mdi trifdng nifdc) khdng ddi, tif ddng hod chgn cdc thdng sd hinh hgc (hinh ddng va tie't dien) CTTKTL hgp ly detdi trgng sdng tdng cdng tdc dung len CTTKTL Id be nhdt. lfng vdi tdi trgng be nhdt ndy, hdy tinh xdc sudt vd cdc dgc trifng so cua tdi trgng sdng ngdu nhien tdc dung len cdng trinh".

4. Ccf sdr danh gia DTC vc dp ben ket cS'u cdng trinh dffdi tac dung cua tai trpng .song ng§u nhidn.

Dffdng ldi chung de ddnh gid DTC ve dp ben ke't ca'u cdng trinh dffdi tdc dung ciia lai trpng sdng ngau nhien dffcJc bidu dien tdm tdt theo sd dd sau:

S ^*''

^

A. L

w Q Oi,)

•

K

G

S ^®^ AF

H

^»

SpF<"^

q (»)

' ac

P(t)=Prob,.,,,{a(r)<(j„,Te[0,t]}>P„ ₍₁₁

5. Cac phd sdng ffng dung trong tfnh dang chung:

toan CTB. ^^^.di) = (A/o').exp(-B.co') (2) Phd Pierson - Moskowitz P-M; phd Irong dd: A,B Id cac thdng scYciia phd.

Jonswap; phd Breschneider; cdc phc^' nay cd

68

sd thdng 3 nam 2010

(4)

I Bieir^tl

t

0)^ CO (rad/s) C0„

6. Xac djnh tai trpng song tac dung len CTTKTL khd'i tron xoay

~ t b (rad/s)

®

r.

/

f ,

i . T ^ T * T J Y

^

0

1 n(n,, n,)

r.

[ T T K T — ^

r, /

Y

0

r

FTmh 2. CTTKTL dang khd'i Iron xoay HTnh 3.Sd dd bdi lodn phang

a. Cdng trinh thffc; b. Mat cat dffng; c. Mat cat ngang The sdng ldng cc)ng (nhieu xa) dffdc xac dinh theo cdng thffc sau:

(t>{x,y,z,l) = [(!),{x,y,z) + (t>,{x,y,z)]e"^ (3) Trong dd:

- The sdng ldi :

co.H ch(k.y) . ., x

- The sdng phan xa la nghiem ciia phffdng irinh Laplace:

VV,(.v,>',z) = 0 (5) - Ap lffc sdng len bien vat the theo phffdng

phdp tuye'n dffdc xdc dinh theo cdng thffc:

Fix,y,z,t) = -p-:^{x,y,z,t) (5, dti

at ^

Thay (6) vao (9) va bie'n ddi la dffc;c:

F{x,y,z,t) = -icopy, ix,y,z) + t/>j(x,y,z)]e""

= Fo(x,y,z).ri(x,l) (7) Trong dd:

Fo{x,y,z) = -iap[tpi{x,y,z) + (pj{x,y,z)]

.2///.e'*-"

Ham sdng be mat:

Ti(x,l) = H/2. e - i " " "

(8) (9)

Sd thang 3 nam 2010

69

(5)

S Bien^a

DI£N DAN KHOA HOC Sau khi rdi rac hod be mat ffdt cua vat the

Ihanh lffdi cac phin iff ta qui tai trpng sdng ve cdc mil phan iff. Ap lffc sdng theo phffdng phap tuye'n nj ciia phin tff j cd dang:

Fo^=^s\Fo{x%yl,z'^\ (10) Thanh phan ciia Foj(l) trong he toa dp De

cac va vie't dffdi dang phffc:

Fa] (0 = Fo^ .n^ .rj{x, t) = {Ajx+ i.Bjx).nix, t) Fo]{t) = Fo^.n^T]{x,t) = {Ajy + i.Bjy).ij{x,t) Fa] (t) = FOj n^j rj{x, t) = (Ajz + i.Bjz).T]{x, t)

y = r ^ (11) 7. Bieu d i l n phd tai trpng sdng SFF (co)

qua phd mat song Sriri(©)

SFXFX(®) = [Ajx- -I- Bjx-]. STiTi(ra) =

= Sox. ST^T^(ra)

SFyFy(ffl) = [Ajy' -I- Bjy']. S^TI((B) =

= Soy. STIT^(CO)

SFZFZ(CO) = [Ajz- -I- Bjz-]. S,^^(co) =

= Soz. STin(co)

SFF(M) = [SFXFX(«)' + SFyFy(co)' + SFZFZ(®"1"^ =

= So. STIT,(CO)

So = [ S o x ' + Soy--t-Sor]"= (12) 8. Xac dinh cac dac trffng sd'cua phd tai

trpng sdng

- Phffdng sai cua phd lai trpng sdng : Dx= J SFXFX (a))<Jco= I Sox.ST^Ti(w)dco Dz= [SFZFZ (oD)da)=J Soz.STiT,(ro)dco (13) DF= I SFF (co)da) = J So .ST,Ti(K))do

- Dp lech ciia phd lai trpng sdng:

ax = (DO'^

a z = ( D z ) " \

aF=(DF)"-' ^ __ (14) - Xac dinh xac sua't cua phd lai trpng sdng:

Fc

I-o ) = J

P,(Fx < I-'

Pz(F

Fc

^L < Fo) = J

Sox.Sriri(co)d(o

Soz.Sriri(a))d© (15)

Fc

P F ( F < F O ) = J- \ So .SriTi(co)dco

oo

9. Xfiy dffng thuat toan va lap trinh 9.1. Xdy diXng thuat todn

Gia sff cdng trinh dang khd'i trdn xoay(ddt trong mdi trffdng bien cd dp sau nffdc la do) tiet dien bat ky, ta chia cdng trinh theo chieu cao thdnh n doan, moi doan i ed the coi la mdt tru trdn ddc trffng bdi hai thdng sd'hTnh hpc: Hi (chieu cao doan i) va Di (dffdng kinh doan thff i) (Hinh 4). Ta xay dffng dffdc bdi todn td'i ffu sau day :

Cho trffdc dp sau nffdc do[m] vd dien tich xung quanh mat ffdt ke't ca'u DTXQo[m2]. Xdc dinh cdc thdng sd' Hi, Di vd n (sd' doan) thoa mdn dieu kien:

HI-hH2-h...-l-Hi-i-...-i-Hn < do

(Dl.Hl-i-D2.H2-t-...Di.Hi-h...Dn.Hn).7t<DTXQo de cho tdng tai trpng sdng tac dung len mat ffdt:

Fl-i-F2-i-...Fi-f...Fn = Ftc la be nha't. Tff dd xdc dinh xdc sua't vd cae ddc trffng sd' cua pho tai trpng sdng.

On Dl 01

/• / / / ^ .

Hinh 6: Sd dd hoa

9.2. Xdy ddng chUdng trinh phdn mem Tren cd sd nghien cffu ly thuye't, chiing tdi da xay dffng dffdc thuat todn vd viet dffdc bd chffdng trinh phan m e m (mang ten DTCPTTSKTX) chuyen dung Iff ddng hod

"Xdc dinh phd vd DTC tai trgng song nhieu xg tdc dung len CTTKTL co hinh dgng khdi tron xoay tiet dien hdt ky hang phiidng phdp PTB ", sd dung ngdn ngff FORTRAN 77. Bd chffdng trinh gdm 1 chffdng trinh chinh vd 10 chffdng trinh con. Sd do td chffc chffdng trinh dffa tren hinh sau [HTnh 5]:

70

Sd thdng 3 ndm 2010

(6)

Bien^^bd

MAIN PROGRAM

SUBROUTINE NDKB(1)

SUBROUTINE NFMAT(2)

SUBROUTINE NCX)SCP(7)

I

SUBROUTINE NSLNPD(3)

SUBROUTINE NINTER(4)

ROUTii SUBROUTINE!

PH0PM(5)

SUBROUTINE

1

DLPH0(6)

I

SUBROUTINE NINTE(8)

SUBROUTINE NBESJ(9)

SUBROUTINE NBESY(10)

H i n h 5 . S d d d t d De kiem tra phffdng phdp vd dp tin cay ciia chffdng tnnh DTCPTTSKTX chung ldi da tinh lodn cho mdt sd' trffdng hdp ddc biel de so sdnh vdi ket qua tinh theo cdc phffdng phdp khdc da cd.

10. Ap dung bp chffdng trinh DTCPTTSKTX de tinh cdng trinh trong didu ki0n Vi^t Nam

10.1 .Dat bdi todn khda sdt (Hinh 8):

CTTKTL dang khd'i Iron xoay ddt d viing dao chim them luc dia Viet Nam vdi:

-I- Cdc sd'lieu ve mdi trffdng bien:

- Van td'c gid: 50 m/s;

- Chieu cao sdng: 13 m;

- Chieu ddi sdng: 120 m;

- Dp sau nffdc ddt cdng trinh: do = 21 m;

-I- Sd'lieu ve ket ca'u nhff sau:

- Dien lich xung quanh mat ffdt: DTXQo = 3300 m';

- Chia thanh 3 doan bang nhau n = 3:

H1=H2=H3= 7 m;

- Doan 1 cd dffdng kinh: Dl = 75 m;

-I- Tim cdc thdng sd' D2 vd D3 dc cho Flc=Fl-i-F2+F3 la be nha'l;

-•- Xdc djnh tdng lai trpng sdng be nha't;

+ Xdc dinh xdc xua't vd cdc ddc trffng sd' ciia lai trpng sdng ffng vdi tai trpng be nha'l.

10.2. Ke't qua linh phd vd xdc sua't tai trpng

chffc chffdng trinh

sdng linh bang phan mem DTCPTTSKTX:

BAI TOAN T U O N G TAC G I O A SONG NHIEU XA y d l CTTKTL

I. SO LIEU T I ' N H :

- BAI TOAN CTTKTL khd'i iron xoay - Chieu cao sdng H= 13.000 m - Chieu ddi sdng L= 120.000 m - D d s a u nffdc d= 21.000m

- Khd'i Iffdng rieng nffdc RO= .102 T/m' - Gdc tao bdi phu'dng sdng vdi true kdt ca'u anfa= .000 dp

- Sd'diem chia tren vanh Nv= 12 - Sd'phan iff tren vanh Npl= 12

- Sd'doan chia chieu cao de linh Nd= 10 - Sdphan doan Npd= 3; H1=H2=H3= 7.000m - Dffdng kinh phan doan 1; Dl= 75.000 m - Dien lich xung quanh mat ffdt DTXQo=

3300.000 m

n . KET QUA TINH TOAN II.l. Kich thffdc ke't cS'u:

- Dffdng kinh phan doan 2; D2= 50.000 m - Dffdng kinh phan doan 3; D3= 25.079 m

Sd thang 3 ndm 2010

71

(7)

S B i e n ^ ^

DI£N DAN KHOA HOC n . 2 . Tong tai trpng song be nhS't:

P1XT[T] PIZT[T]

IT/C 1 .427E-1-04 1 OOOE-i-OO 1

n.3. Bien dp phd sdng:

Doanlhff: 10; Dp cao Y= 19.950 m

jDiam] Sox[T2]

1 ll 1 2|

1 3|

1 4|

1 5|

1 6|

1 7|

! ^1 1 9|

1 lOi I HI 1 12|

I 10|

.845E+04 1 .824E+04 1 .181E+04I .180E+04I .824E+04 1 .845E+04 i .844E+04 1 .824E+()4 1 .181E+04I

.180E+04I .824E+04 1 .847E+04 1 .740E+05 1

Soz[T2] 1 .OOOE+00 1 .OOOE+00 1 .OOOE+00 1 .OOOE+00 1 .OOOE+00 i .OOOE+00 1 .OOOE+00 1 .OOOE+00 1 .OOOE+00 1 .OOOE+00 1 .OOOE+00 1 .OOOE+00 1 .OOOE+00 1

II.4. Xac sufl't va cac dac trffng sd'cua tai trpng song:

- Xac sual lin cay ciia phd lai trpng sdng:

P= 0.976

- Phffdng sai: D = 0.147 m2 - Dp lech: Sima = 0.383 m 11. Ket luan chung:

Cd the diing bp chffdng trinh DTCPTTSKTX dd xac dinh bien dp phd lai irpng sdng lac dung len cdc cdng trinh: trii d'ng, cff vay d, cdng trinh trpng lffc, phffdng lien ndi...

TAI LIEU THAM KHAO

1. Pham Vdn Gidp, Nguyen Ngpc Hue, Nguyen Hffu Da'u, Dinh Dinh Trffdng (2000), Be cdng va de chdn sdng, NXB Xay dffng. Ha Ndi.

2. Pham Vdn Gidp, Nguyen Hffu Da'u, Nguyen Ngpc Hue (1998), Cdng trinh ben cdng, NXB Xay dffng. Ha Ndi.

3. Lffdng Phffdng Hau, Hoang Xuan Lffdng, Nguydn Sy Nudi, Lffdng Giang Vu (2001), Cdng trinh bdo ve bd bien vd hdi ddo, NXB Xay dffng, Hd Ndi.

4. Tran Minh Quang (1993), Sdng vd cdng trinh chdn sdng, NXB Giao thdng van tai, Hd Ndi.

5. 22TCN-222-95 (1995), Tdi trgng vd tdc ddng (do sdng vd do tdu) len cdng trinh thuy.

Ha Ndi.

6. Phan Van Khdi - Ca sd ddnh gid do tin cdy- NXB K H & K T 2 0 0 1 .

7. T.H.Dawson- offshore Structural Engineering,USA 1984.

8. Dynamics of marine structural - C.R.l.A,London 1977.

9. C.A.Brebbia - The Boundary Element Method for engineer,London 1980.

10. C.A.Brebbia, J.C.F.Telles, L.C.Wrobel - The Boundary F>lemenl

Techniques, M. 1987.

11. FASTOR - ClTIM,France 1988.

12. T. Karamanxki - Phffdng phdp sd'trong cd hoc ke't ca'u - NXB KHKT 1988.

72