DIEN DAN KHOA HOC CONG NGHE
PHAN [Sm CUA CONG TRJNH LAN CAN HAM
(Tiep theo ky trudc)
3. Su tuong tdc giiTa tunen - moi trirdng ddt - nha
Nhu dd bilt: khi thi cdng edng trinh ngim bdng phuong phdp ddo ngim hay dao md, it nhiiu diu gay nhijng blin d^ng them nhu chuyen vj ddng vd ngang, bj udn (vdng xuing hay vdng Idn), nghidng hoac nUt...
ddi vdi nhd/cdng trinh Idn can. Mdc dp hu hai vUa neu phy thudc vdo mdt sd ylu t i nhu la:
- Dp cdng cua nha (kich thudc va dang hinh hpc, vdt lieu xdy dung, chi tilt ciu kien...);
- Dd cdng cda nin va loai dit;
- Dd sdu vd kich thudc hd ddo/tunen;
- Vj tri ciJa nhd dii vdf hd ddoAunen(ndm trong vung vdng/ving, ddi xdng hay nam Idch so vdi mat bdng nhd);
-Trpng lucng eua nhd/cdng trinh.
Do ed nhiiu nhan td tucng tdc nhu vdy (xem hinh 3.1) eho ndn ed nhiiu con duCng khde nhau nhuthue nghiem, bdn thue nghiem, thf nghiem md hinh ly tdm, gidi tieh hay phuong phdp sd... de giai bai todn tuong tdc vda ndu.
PGS. T S . NGUYEN BA KE Hoi CO hoc €)kt va Dia Ky tiiudit Viet Nam
Nh^cSng trinh
Hint) 3.1: Quanhd giOa cic thinh phin Uong m6i tddng tic tunen - dit - nhi
Ong suSt chinh cAhi^u.
90 cung cOa i l l
Md td phdn ung vUa ndu bang md hinh cP hpc nhu trinh bay tren hinh 3.2a. Ta thiy tuy su tilp cdn cita nha dii vd^ cdng trinh ngim md nhd bi udn vdng Idn (hoggin zone) - vung bj keo - hoac udn vdng xudng (saggin zone) - vCing bj nen...
Burland (1995) sd dung ty sd biln dang (/L) de thay cho biin dang gdc (p) nhdm ddnh gid su hu hai nhu trinh bdy tren hinh hinh 3. 2b. Dd Idch tuong dii (A) Id trj s i chuyin vj Idn nhit ciia kit ciu giua hai dilm, cdn t^ sd biin dang Id ty sd gida dd lech tuong dii vd khoang cdeh L gida hai diem va tfnh theo cdng thde:
DRH = At,/L, vd DR, = A3/L, (3.1) Biin dang gdc (angular distortion), mdt trong
Hinh 3.2. Sd dd cd hoc vl phin dng cua cdng Irinh lin cin tunen (a) vi cua lifdng nhi trong vung vdng vi vung vbng jtrbi (b)
(Theo Giorgia Giardina etaL, 2008)
• ©
Vung vong •(•^asi^^-^ \ A < 0 VCing vSng/tr6i nhdng tieu chf dung d l ddnh gid hu hdng nhd Idn can cdng trinh ngim, se Idy la duong (p>0) hoac dm (p<
0) tuy theo vijng vdng hay vung vdng/trdi cua nin dit do cdng trinh ngdm gdy ra cho nhd tudng chju luc bdng gach (hinh 3.2bJ.
3.1. Cac thong sd danh gii hu hai nha va each xic djnh
Buriand (1995) da dung 9 thdng sd khac nhau de xet biin dang vd dupc md td vd cfinh nghTa nhu trinh bdy tren hinh 3, 3.
Theo hinh ndy:
+ Dp lun: Id chuyin vj thdng ddng eua mdt dilm.
Dp lun duong ehi chuyin vj di xudng (hinh 3. 3a);
+ Dp lun tuong dii hay dp chenh lech lun S^ Id su sai khac giiJa 2 dp lun (hinh 3. 3a),
+ Gdc xoay hay dp nghieng (hinh 3. 3a) khi so sdnh dp Idn 2 diem vdi phuong ndm ngang;
+ Biln dang gdc (angular strain) gida 2 phin vong vd vdng (hinh 3. 3a);
+ Dp vdng tuong dii A^^ la chuyen vj tuong ddi Idn nhit giua 2 dilm each nhau L. Ldy tri sd duong khi vdng (hinh 3.3b);
+ Ty s i dp vdng DR=/AL (hinh 3.3b);
+ Dp nghieng a la st/ xoay eua ddy mdng edng hoac cda gilng ddng. Rit khd xae djnh khi mdng mim (hinh 3.3c);
+ Biin dang xoay tuong ddi hoac cdt (relative rota- tion /angular distortion) p Id suxoay cda dudng thdng NGUdl XAY DUNG SO THANG 9 & 10 • 2014
® ® o o
(a)
""--J^.
Sy, mn
^ • C j o ^ M
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Hinh 3.3. Cic thdng so bien dang cua nha (Theo Buriand. 1995) n i l 2 d i l m nghieng tuong d i i (hinh 3. 3c);
+ B i i n dang ngang trung binh e,, la dp dan ddi L trdn c h i i u dai L, Eh = U L
Tat nhien cdc thdng s i b i i n dang vUa neu chi dp dung cho bai todn b i i n dang phdng.
Trong thuc t i , khi danh gid mdc dp h u hai cua cdng trinh Idn can cdng trinh n g i m ngudi ta thudng dung cdc tieu clii ehinh nhu bien dang gdc p, b i i n darig ngang e^ (cd khi ky hieu s j xem la b i i n dang keo (ldy ddu dueng +) n i u nhd ndm d v u n g keo (hoggin zone) hoac b i l n dang nen ( l i y d i u dm -) n i u nha nam trong vCing nen (saggin zone) vd b l rdiig cac v i t ndt tren tudng. Cach xae djnh cdc thdng s i vda neu xem tren hinh 3.4.
m
B\£H D W O NOANG. & .
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Et = &L/l-
BI^N OANO CkfC DAI
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u
Hinh 3.4. Bien dang xoan gdc fcit vk bm dang ngang tm ket ciu mi dat cluiyin vi (Tlieo £ J. Cording et ai, 2010) Trong tri/ong hap c6ng trinh n g i m thi cong theo phiicffig phap dao ng§m thi chuyen vi ngang va g6c xo§n (bi^n dang cat) di^oc tfnh theo 6'e nghj cung cCia E.J. Cording et al., 2008 nhii trinh bay tren oSc hinh 3.5 dSn hinh 3.8.
C i c thong s6 cua p l i l u lun duoc tfnh (E. J. Cording et al, 2008) hay quan t r j c Xil cong trinh thuc t l nhtf sau:
+ BS rdng cua ph§u iijn: W = 2, 5i = r + ztanb"; (3.2) + B p lun I6n nhat cua p h l u lun: 5 „ | „ = V^/W; (3.3)
PHAN UfNG CUA CONG TRINH LAN CAN H ^ + Goc nghieng trung binh (Average Slope) AGS=5„„/W. , (3.4) G6c b" = 26° ddi ydri o4t va b" = 40" doi vd« sit (±51.
Trong danh g\& c§n chu y:
+ Do CLtng ngan^ cua nha:
- Dim va kit cau khung se lam biln dang ngang
- . 2 3 , . . . 1 . J - .
«*- r , 1
^m m
< 1 _ . .
»m-,i,«l5KK;«S!9^™2
^ ^ • w F Chuyei^ VI ngang ion rri3l,i>S B H o ^ e m uon 1 S a H l ^ f l
/ i 6 , . 1/3 6„, (tan b/0.5) y 6i= l . l ( W ) t a n b
" 1/ 2 to 1 X '.!iMif,M;ilJ,w
^ ^ ^ H ^ ^ ^ H trung binh | Hinh 3.5. Tinb chuydn vi vi biin dang ngang theo tanh. 6„ va IV
Hinh 3.6. Tinh p khi mdt ddn nguyen nha nim trong phiu tiin H
_w__^^^^H
^ ^ P ^ M I xs^
T^^ien dang goc = So doc - do nghieng |
^ B i e n dang goc la su'lhay iiii diD doc • B n s t monij qiijB 2 don nguyen |
• Oiendanggoc.anlaannhat.tlfititheo 1
P i CSm /w) (Lfc/w) Hinh 3.7. Tinti ^ l<hi ddn nguyen 1 tiitn dang g6c, ddn nguyen 2 ngliim
Hinh 3.8. rii/i p ktii nlii bi nghilng, thung bi may iam giam nglneni
NGI/Cfl X A Y D O N G SO T H A N G 9 & 1 0 - 2 0 1 4
PHAN llTNG CUA CONG TRJNH LAN CAN HAM cua nhd nhd han biln dang ngang cua ddt;
- Biin dang cua ddt thudng tap trung d mep nhd, d khe lun/khe co dan nhidt giua cdc don nguydn hode d nhiJTig ehd ylu cOa nhd.
+ Dd Cling ching cdt cua nhd:
- Dd Idch gdc/bidn dang cdt p < AGS (gdc nghieng trung binh ddy mdng);
- Dp cUng chdng cdt tuong dil cOa nhd nen theo mdng;
- Dd cUng chdng cdt bj giam di khi ed nhiiu Id cua va ed cdc khe nUt.
Di nam vUng them cdeh xae djnh cdc thdng s i dung d l ddnh gid hu hai cdng trinh do lam him trong bdi tilp theo se trinh bdy hai vf du tU kit qud quan trdc cdng trinh thut t i .
3.2. Vi du cich danh gia su tuong tic glUa tunen -nen dat -nha
Vi du 1: Cording et al (2001) da djnh nghTa biin dang cOa edng trinh nhdm danh gia su hu hai dua trdn trang thdi biln dang trung binh. Biin dang cua tudng dupc xdc ^nh bdi do dac theo phutmg thang dung (v), theo phutfng ngang (I) ehuyin vi (A^ B„ C„ D„ A, B, C|
D|) tai 4 gdc (A, B, C, D) ciia nhd khung dupc the hien d hrnh 3.9 (Moorak Son, 2003).
TCr s i li^u do dac, theo djnh nghTa cd t h i xdc dtnh cdc thdng sd biln dang:
+ Dd die trung binh (average slope) Id su thay doi dd die tgi day nhd tren chiiu ddi L dupc djnh nghTa:
S = - (3.5)
(- D$ nghieng (tilt) la g6c xoay ciia tuftng duoc xae
^JC,-B,).(D.-A,) ^^^^
2H
r=
(C.-B,) H (3.6)+ Do l^ch goc (angular distortion) (p) la bien dang cit ducrc xdc dinh:
p=S-T (3.7) + Biln dang ngang tai dinh (lateral strain, T)
(si„(T)) I& sii thay doi chuyin vj ngang tai dinh tren todn chilu dai L:
' • , . ( n = ^ ^ ^ (3-8) + Biln dang ngang tai dSy (lateral strain, F) (6|a(F))
\k sir thay doi chuyin vj ngang tai ddy tren toan chilu ddiL:
f « ( f ) = A,-B,
(3.9) Si!r dung cac c6ng thijic tr§n de tinh toan lly tir vf du ciia cong trinh thtrc t l tren hinh 3. 9 nhu sau:
Tai nhjp 1: 38,77-16,54 , Do ddc trung binh S = —— = 3,64jd0
14 7*^ — 4 8^
Do nghieng T = ^-^ ^ = 1,62x10"'
• 6100 Biln dang cit = (3,64 - l,62)ilO' - 2,0itl0>
Biln dang ngang tai dinh 30,90-14,73 , ^ ^ , „ 3 E i „ = ^ =— = 2,65x10 '
6100
Biln dang ngang tai day m6ng 8,92-4,83
6100 = 0,67x10"^
Moorak Son, Edv^ard J. Cording (2011) da dijng phoong phdp s6 de nghien cuu sir hi/ hai cong trinh vol mpt s6 loai hinh kit cdu thudng gap (tu^g chju luc blng gach va nha khung co chen gach va khong chen gach) tren nin dit mim va cijfng ufng vcri cdc giai
h - t -
^
5 0 . 9 0 ,
S.92
9 . ! 2 ,4.7.1 '6.51 14.4H
• D D D
A 4.83 J B '.w B.77 16 M
6 35 ]4_4B -
' a D D D
1
6.12
\~
Hinh 3.9. linh loin bien dang cOa cdng trinh dedanh gii sd thiit hai dean lun khde nhau khi kit ciu Idm viec trong giai doan dan hdi va khi cd xuit hien ndt. TU kit qua ndy da tfnh eac gid trj ung vdi tdng diiu kien dit nin vd loai hinh kit ciu khac nhau.
Vi du thd2: day Id kit qud quan trac 2 ngdi nhd 3 tdng, dim dd sdn bdng gd cd tudng gach chju luc song song vert true hdm tunen G thupc he thing metro Washington, dit nin gdm cdt chat, cudi sdi vd set eUng (E. J. Cording et al, 2008).
Tren cdc hinh 3.10 din hinh 3.11 trinh bay kit qua do Ilin vd chuyin vj cung nhijng tfnh todn cac thdng s i biln dang tuong Ung vd dupc tong hpp trong bang 3.1.
Ben phai
Washington Metro: G Tunnel:
Khien dao tioiig cat chat va set ci'nig Hinh 3.10. Kit qui quan hie lun mat dit NGUdl XAY DUNG SO THANG 9 & 10 - 2014
Bf nghieng va bien d^ng goc
tj u6n:tach khoi l u ^ g lan can
(mm) p H#ak a ,piSnil?nag6c Q, (BQ nghi§raAl6c nha
^,0^ rhieng Id^ xem rina cung
0$ <f61: ngang nhek
Hinh 3.11 Kit qua quan trie bien dang vi tinh toan cac thdng s6 Bang 3 . 1 . Td'ng hpp k i t qua tinh toan theo sd lidu
quan trdc 2 nhd g i n ( x l O ' l
Bo d6c mat i t AG.S fid nghieng DO d6c - do nghigng ndo b§ng Extensomet
Nhis61 4 4 - 0.8 = 3.2*
1 9 4 - 1 9 = 2.1
1.8to2.0**
N h i s l 2 0.6
NA 0.3 0.8 • 0.3 = 0 5
0
* Cdc tddng cOa nha 1 va 2 bi tach ra se din den iam giSm gdc fa hon la A G. S
** Cda bi ket va xuat hien vet ndt nhd do cit Bien dang ngang d day
mdng
Mn dang ngang d dinh nha
< 0 . 1 * "
< 0 . 1
*** Nha so 1 a trong vung cd bi^n dang ngang nhd
0.3 0. 8 " * + Khe hd 5mm din
den tach dam mai khdi tddnq ben trai (Con nOa)
PHAN IJfNG CUA CflNG TRINH LAN CAW Hk
THU DO HA Npl H U 6 N G DEN THANH PHO...
(7/gp ffteo trang 58)
6. Kjcli ban nao cha cac (Td thi m& d H<t N6i ~ fl6 HoSng An, TC Kien Trijc Viet Nam, thang 8/2008
7. BSD cao dd dan - Vien Nghien cilu Phit tnSn TR HCM, Hdi thdo khoa hgc 'Tm chi xay di/ng W. HCM XHCN, tin minh, him daT TR HCM ngay 9/12/2008
8. Tij' lang lua dSn thimh phd tiMig lai - Pham HDng cudng, TC Kidn trdc Vidt Nam, thang 5/2008
9. Quy hoach vA ban ilnh ciia chinh quy^n - Ld Quang Nhue, TC Kien trdc Vict Nam, thdng 5/2010
10. Tieu chi cho m6t Ha NOiph^t trien ben vCmg ~ Nguyen Bang Son, TO Kidn trdc Vidt Nam, thdng 5/2010
11. GiSi pbAp cho hdnh lang xanh • Pham Sy Liem, TC Kien true Viet Nam, thdng 5/2010
12. Kinh nghiem quy hoach chung thu dd Hd N6i dhn nm 2030 tam nhin 2050: Ba thi ve tinh va bao ton dd thi ldi - Si/
cdn bSng ddng trong gua trinh phit hien dd thi ci/c Idn • Ng6 Trung Hal & Nguydn Trdc Anh, Ky ydu Hdi thdo khoa hoc PhSt tri Jn dd thi bin vitng, TR HCIVl nam 2010
13. Phat trien hd thdng dd thi qudc gia bdn vOng - Lfi Hdng Kd, Ky ydu Hgi thao Phdt triSn dd th| bin vmig, TR HCM, nam 2010
14. Oi/y hoach do thi vdi hudng tidp cdn bdn vdng - La thi Kim Ngdn. Ky ydu Hoi thao khoa hoc Phattri^n bin vflng,TR HCM, nam 2010
15. JUdng lal cua nhdng lang qud tai viing phia Jdy Hk NBi - Michael DiGregorie, TC Kien true Vidt Nam thdng 12/2012
16. Thanh pho Hi Chi Minh thi kj XXI, HiMng tdi giao thdng dd thi ding cap the gidl - Siemens, giz & Hlds, thdng 3/2011
17. Thanh phd xanh - Nguydn Bang Son, TC SG BT - XD thang 5/2012
^8.Kdt hdp edy xanh vdi mat nUdc - Nguydn Bang Sdn, TCNgKdi 60 thi thdng 12/2011
19. Thinh pho da truydn thdng ~ thdnh phd thi kf XXI- Nguydn Bang Son, TO Ngudi xay Dung thang 3/2012
20. Hudng tdn thdnh phd sdng tdt - Nguyin Bang Son, TC Ngudi Xdy dUng thang 10 ndm 2012
21. Quy hoach chldn lifidc hdp nhat - Nguydn fidng Sdn, TC Quy hoach Xdy dung, thang 12/2012
22. Chlen lUdc qudn ly tang tnldng dd thi - Nguyin Bang Son, TO Quy hoach Bd thi, thdng 12/2012
23. Quy hoach dd thi hidn dai bdn sac dia phddng • Nguyin Bang Sdn, TC Kiin trdc, thdng 10/2013
24. NhCmg giai phdp thuc hidn trong qud trlnh lap vd tri^
khai quy hoach cua Thu dd Hd Ndi - Nguyen Vdn Hdi, TC Klfc Trdc thdng i/2014
25. TP. HCM hi/dng den thinh phd van minh - Nguyh Bang Son, TC Quy hoach Bo thi s6 16 ndm 2014 NGUdl XAY OI/NG SO THANG 9 & 10 • 2014
