TraoOoi^i^^at
PHUONG PHAP Xtf LY SO U E U QUAN TRAC LIEN TUC XAC DINH THAM SO DAO DONG C 6 N G TRINH
PGS. TS. VU THANG ThS. Bill DUY QUtNH
ThS. VU THAI HA Trudng Dai hoc Xay dung Tom tat.
Bai bao giai thieu kit qua nghien cim mo hinh do lidn tuc va phuang phap xir ly so lieu do di xac dinh cac tham so dao ddng cdng trinh xay dung dua tren kit qua do cua cac thiit bi hien dai, cd kha nang tu ddng do lien tuc nhu GPS, TBBT.
tVt&dau
Nhyng cdng trinh xay dyng dae biet do tac ddng eua ngoai iyc dan den bj dao ddng, rung lac iam anh hydng tdi cdng tae trac dja cung nhu' an toan trong qua trinh thi cong, dp on djnh trong thdi gian khai thac sy dung. Viec xac djnh cac tham sd dao ddng dya tren kdt qua do cua cac thidt bj hidn dai, cd kha nang ty dpng do lien tue nhy GPS (Global Positioning System), TDDT (Toan Dac Dien Ti>). Xy ly ket qua do xac djnh cac tham so dao ddng ia ndi dung bai bao de cap
1. Tham so dao dong cong trinh De xac dmh dao ddng, rung iac cdng trinh can quan trie sy thay doi tuIn hoan vj tri nhiyng diem dac tryng trdn cdng trinh.
Dao ddng cdng trinh ed tfnh tuIn hoan, phyong trinh dao ddng cd dang [7],[8]:
Qt = ao + a,cos(tot) + b,sin(a)t) (1) trong dd :
Q, la sy chuyen djch cua cdng trinh.
t ia thdi diem eua dao dpng;
t i n so gdc oi='2if
ao ia dp djch chuyen trung binh cua doi tyong;
ai,b, ia eac he sd Fourier cua ham sd.
Tan so (f) la so lan dao ddng trong mdt don vj thdi gian.
Bien dp dap dpng A = V^i^ + ^J la khoang each giya hai thdi diem eye trj liln ke cua diem quan trac dao dpng.
Ddi vdi cdng trinh xay dyng cac tham sd dao ddng chinh c i n xac dinh la:
- Bien dp dao dpng (A), t i n so (f), chu ky dao dpng (T).
- Dp tre (At) la thdi gian tir khi ngoai Iyc tac ddng ddn khi cdng trinh dao dpng.
Ngoai ra c i n xac djnh:
- Dp chfnh xac do m, c i n thidt de xac djnh dypc cac tham so dao ddng.
- Thdi gian toi thieu t^ c i n thidt giya hai trj do lidn nhau de day trj do dypc coi la iidn tuc.
2. Mot so dang dao dong dac trung 2.1. Dich chuyen dap chan cong trinh thuy to'i, thuy dien
Dap Chan cua cae cdng trinh thuy lpi, thuy dien bj tae ddng mot phia do dd cao myc nu'dc trong hd chda d phia thypng Iyu nen bj djch chuyin. Sy djch chuyen nay cd mdt phin mang tinh tuan hoan, thay doi theo dp eao myc nyde trong hd 6 n^ia thypng iu-u cua dip. Chu ky dao ddng phu thupc theo Iu'ong mya d Iyu vyc phfa
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thu-p-ng ngudn va thu'd'ng cd chu ky la mdt djnh cae tham so can thidt du'p'c xem la day nam. trj do thu'dng xuyen, lien tuc.
2.2. Dao dgng nha si4u cao tang Nha sieu cao tang do tac dpng cua ngoai Iyc, chu yeu la gid, lam eho nd bj dao ddng.
Cac dao dpng nay cd bien dp phu thudc vao cu'dng dp va hu'dng gid, thu'd'ng la tCr cm ddn dm, th|m chf td-i met [4]. Tan sd dao ddng thu'dng tfnh theo giay. Dao ddng trong nha sieu cao tang lam anh hu'd'ng to'i cdng tac trac dja dam bao thi cdng, dac biet la cdng tac chuyen true len ting. Md hinh quan trac xac djnh tham so dao ddng nha sieu cao tang a hinh 2. Ngoai ra cdn cac thap sieu cao, c i u treo kich thu'O'c lo'n, mije nu'dc a cac cang bien...cung c i n du'pc xac djnh cac tham so dao ddng.
2.3. Dao dgng cua cau treo, ciu day vang
Cdng trinh cau day, elu treo hien nay cd ket cau phipc tap, kha nang mang tai va vu'pl nhjp Idn. Do chju anh hu'dng cua ndi lye dudi tac ddng cua tai trpng va mdi tru-dng ben ngoai gay len eae cua dao ddng tru thap, dam c i u , cap day vang so vdi trang thai tTnh cua e l u . Cac dao ddng nay thu'dng cd bien dp, cu'dng dp tu- cm ddn dm.
T i n so dao dpng thu'd'ng tfnh theo giay. Viec xac djnh cae tham sd dao dpng la ca sd de thye hien cae hoat dpng kiem tra va bao tri cdng trinh c i u .
3. XiP ly so lieu quan trac lien tuc 3.1. Loai sai so tho trong diy trj do Phu'ang phap quan trie hieu qua de xac djnh tham so dao ddng cdng trinh la do lien tue. May TDDT cd kha nang t y ddng do va lu'u so lieu vdi t i n suat tinh theo giay. Thidt bj do GPS cd kha nang ty dpng do hang trieu trj do trong mdt gid' va ket xuat den 20 ket qua/giay [6].
Day kdt qua do cd thdi gian giOa hai trj do ngIn so vd'i chu ky dao ddng, du de xae
Trong day ket qua do lien tuc, trj do ed sai sd vu'pl qua gidi han eho phep (la cac trj do CO sal sd thd) c i n loai bd.
Thuat toan loai sai s6 thd phu hpp vdi day trj do lien tuc la "cu'a so tru'pt" [1]. So trj do lien tuc trong mdi ciia so la k = 2 -^ K. Gia tri K phu thugc vao so trj do lien tuc trong mdi chu ky va dp chinh xac cac trj do. Trong mdt chu ky dao dpng neu do lien tuc 30 den 40 trj do, gia trj K phu hpp la 4 ddn 5 [1].
Anh hu'dng cua cac tri do tdi viec xac djnh cac tham sd dao ddng la nhu' nhau, ndu dp chfnh xac kdt qua do va thdi gian g\ira cac tri do la bang nhau. Tru'o'ng hp'p nay eac trj do du'pc xem la cd trgng sd bing nhau. Sau khi loai sai sd thd, day tri do cdn lai cd nhiJng khoang trdng do mdt hoac nhdm vai trj do mang sai sd thd da bj loai tao ra, dan tdi thdi gian giiJa eac trj do trong day khdng bang nhau. Oe tai tao day tri do cung trpng so c i n bo sung bang each ndi suy theo gia tri cua 2 trj do hoac thay doi trpng sd hai tri do liln k l . Trong didu kien cho phep, thi giam thd'i gian giCta hai tri do, dong nghTa vdi tang sd lu'dng trj do lien tuc trong mpt chu ky, se cho ket qua tot han.
3.2. Thuat toan xac djnh tham so dao dgng cong trinh thong qua mgt day tn do Trong hinh 1, canh S'^, la day trj do canh lien tuc khoang each giu'a diem dat may cd dinh M va moc A d vj trf on djnh g i n cdng trinh. Canh S\ la day tri do lien tuc khoang each giiJa diem M va diem 1 d tren dfnh nha sieu cao ting. (Xem hinh 1).
De xae djnh cac tham s6 dao dpng a diem 1, khi do bing TOOT, eanh S'^, chi do mdt sd tri do c i n thilt. Trinh tu' tinh nhu- sau [5]':
Buvc 1. Sau khi loai sai sd thd, tinh tri trung binh cdng Sj" , sai sd trung phu'ang
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mdt trj do m^A, va sai sd tnjng phyong ciJa trj tmng binh cdng m f theo cdng thdc
(2)
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} r" 1 °
1 ° a D D
D D a
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Hinh 1: Md hinh quan trie lien tuc bang TBBT
Bum 2. Tfnh trj trung binh cdng va sai sd cOa cac day trj do lien tuc theo ci>a so trypt.
Moi cya so ed k trj do, k = 2 * K. Gila so d i u tien cd cac tri do td 1 d i n K. Ci>a so thiJ- hai cd trj do tCr 2 den k+1, cda so cudi cung cd cac trj do ty n - k ddn n. Trong day n trj do cd j = n - K cda so. Moi cila so ddu tfnh trj trung binh cdng Sj va sai so mg, theo cdng thi>e (2), vdi cac trj do d cya so thy j ia t y
s;' din sZ,
Buvrc 3. Tfnh dp lech trj trung binh cdng giya hai cya so lien ke thy j va j+1:
AS„„ = 5'"-57 (3)
Trj sd K cOa ci>a so trygt dypc xac dinh khi tfnh dp iech trung binh cho ddn khi hoi tu. Trj so K phLj hpp thydng bien doi tly 3 den 9. Trj so K phu thupc vao dp chinh xac mdi trj do, so trj do trong mdt chu ky, bien do
Trao dot - Y kien '•
"« v^c dinh.
dao dpng va dd chfnh xac can xa L-' V. =inh hydng cua Dp iech ed t h i hieu chinh anh ^^^ y. ^^
didu kien mdi tru'ong thong qu
ly day trj do canh 6n dinh SA [5] de tang them do chinh xac.
Bw&c 4. Xae dinh cac tham so dao ddng - Chu ky dao ddng T:
Xet day dd lech giCra eac cya so trypt, tgi vi tri dd Idch d i i d i u ia ed cyc trj. DO lecii doi d i u t y du'ong (+) sang am (-) ia vi trf circ dai; t y am sang dydng cd cd cyc tieu.
Chu ky dao ddng la tich cua s6 dp lech gida hai cyc dai hoac cy tieu lien k l vdi thoi gian giya hai tri do:
t = No.to (4) trong dd: No la sd dp lech giipa hai cifc
d?i hoac hai cyc tieu lidn ke. t^ la thdi gian giCra hai trj do.
T i n sd f la so chu ky dao ddng trong mot mpt don vj thdi gian
f = 1 / T (5) - Bien dp dap dpng A la khoang each
gida hai cyc trj lien ke
A = Ajt]-Aj (6) Trpng dd Aj va A^i la gia trj cua ctrclrj
thy j va j + 1 .
3.3. Ket qui thuv nhiSm
- Ket qua thyc nghiSm 68 trj do canli TDDT khoang c^ch giya 2 diem on S\rk moc M va moc A dddi chan nha cao ting la S'A va khoang each giiia mdc M va flilm 1 la £'i. Diem 1 d tren ndc nha cao tang bj dao dpng (hinh 1). Bilu dd 1 la kit qua cua tiai day trj do lidn tuc. (Xem biSu dd 1)
Trj xac suat nhit cua 2 canh do la SA = 300,0004m va S, = 301,0128m Sai so trung phyong m8i trj do tfnh theo
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Trao doi - Y kien
ddng canh S^. (Xem biiu do 2)
- Thyc nghiem dd GPS canh S^, S2 va S3 Betsel la
n^sA] = ± 1,8mm va mgn = ± 9,2mm
Sai so trung phu-ang tri xac suit nhat la " ° ' ^ diem A, B va C d cae vj tri on djnh; Ba msA = ± 0,2 mm va msi = ± 1,1 mm canh S4, S5 va Sg la khoang each tu' 3 diem on djnh tai diem D d' ndc nha cao ting, bj Bieu do 2 la sai sd do canh S^ va dao dao ddng {hinh 2). (Xem hinh 2)
301.0000 H 300 3000 - 300.6000 7 - 300.4000 300.2000 300 0000 4IM 299 8000 299 6000 299 4000 -
1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65
Biiu dd 1: Kit qua canh do SA va Sj
BIEU D 6 SAI S O
—«— C ^ SA . ^ ^ Canh SI
Biiu dd 2: Sai so canh S^ va dao ddng canh S-f
Hinh 2: Md hinh quan trie lien tuc bing GPS
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irao aoi - I Kten
Xy ly 6 day trj do lien tue va ddng thdi vdi dpng cac canh S ^ - (Xem biiu 66 3) 132 gia tri mdi day. K i t qua va dp chfnh xac ^ . . ^ ^ . ^ 1^ ^ ^ ^ ^ j ^ g ^^ 3 |,„4„g;\ g d bang 1. (Xem bang 1) ^ ^^ ^.^ ^^. ^ . . ^ p ^^em biiu do 4)
Bleu dd 3 la sai so do cac canh S,.3, dap
Sang 1: Kit qua tinh 6 canh do lien tuc va ding thdi Canh
Trung binli 132 tn do (m)
Sai so tiling phii'o'ng tri do (mm)
Sai so tn trung binh cOng (mm)
s,
320.1578
1.0
0.1 Sz
102.9540
2.4
0.2 S3
319.5309
1.9
0.2
s*
164.0424
19.6
1.7 S5
165.4967
21,6
1.9 St
200.9666
22.0
1.9
Biiu do 3: Dao dpng diim D theo 3 hudng
Biiu do 4: Dao ddng theo 3 hudng va vj tri diim D
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r ^ ',•:;•-.fJa^^^J^^.^
K i t qua XLP ly 6 day tri do lien tuc, xac djnh du'gc eac tham sd dao ddng diem quan trie theo 3 hu'dng va dao ddng vj trf diem.
Khi bien dp dao ddng tu'ang du'ang vai sai sd do thi viec xac djnh dp lech gi&a cac cOa so bj nhilu, can cd su' can thiep thu cdng. Ket qua khao sat cho thiy khi bien dp dao dpng ehf bing mpt nira sai sd do thi dp lech hoan toan bj nhiiu, khdng the xac dinh du'pc eac tham sd dao ddng.
Ndu do mdt eanh, thi chi xac djnh du'pc bien dp dao ddng theo phu'ang cua eanh quan trie.
Ket luan va hirang nghien CLFU - Day tri do lien tue cho kha nang xac djnh eae tham sd dao dpng cua cdng trinh quan trac.
- Day trj do lien tuc cho phep chuyen tpa dp len nha sieu cao ting, n l u xu" ly theo qui trinh phu hpp thi vj tri tu'ang hd giiia cae tryc khdng bj anh hu'dng cua dao ddng.
- Hu'd'ng nghien CLPU tidp theo la hoan chinh phin mem XLP ly so lieu quan trac lien tuc xae djnh anh hu'd'ng cua dao dpng.O
Tai lieu tham khao
[1]. Vu Thang. Bai giang Ca sd Trac dia cdng trinh, DHXD, Ha Npi 2014.
[2]. Nguyen Quang Thang. Bao cao de tai c l p bd B2003-36-53. Qui trinh cdng tac trie dja xay dyng cdng trinh cd chilu cao Idn, Ha Ndi 2004.
[3]. TCXDVN 4453-1995. Ket elu be tdng va be tdng edt thep toan khdi. Qui pham thi cdng va nghiem thu - Ha Npi 1995.
[4]. Huang Sheng Xiang, Liu Jing Nam, Evaluating the precision of GPS positioning for short baseline using long-term data.
Wuhan Technical University of Surveying and Mapping, Wuhan 430079, China, 2001.
[5]. Vu Thang. Trie dja xay dyng thyc hanh. NXB xay dyng, Ha Ndi, 2002.
[6]. Cdng ty co phin thidt bj SISC Viet Nam. Cac thidt bj trac dja va dja khdng gian eua Leiea. 2010.
[7]. Trin Khanh, Nguydn Quang Phuc.
Quan trac chuyen dich va bidn dang cdng trinh. NXB Giao thdng van tai, 2010.
[8]. US. Army Corps of engineers.
Structural Deformation Surveying, 2002.0
Summary
Method of processing continuous monitoring data indentified osciiiation parame- ters works
Assoc. Prof. Dr. Vu Thang, MSc. Bui Duy Quynh, MSc. Vu Thai Ha National University of Civil Engineering
This paper presents results of research into the continuous measurement model and process measurement data to determine the oscillation parameters constructions. When using the modern equipment capable of continuous automatic measurement high accura- cy as GPS, total station.O
Ngay nhan bai: 29/7/2014.
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