KHOA H O C - C O N G NGHE
GIAI PHAP XUf LY SAT LOf DlTOfNG VEN SONG TREN DAT YEU TAI QL. 91 DOAN BINH M Y , AN GIANG
KS. LE XUAN VIET
TS. TRAN N G U Y I N HOANG HUNG Trudng D$i hgc Bach khoa TP. Ho Chi Minh
Tom tat: Diem sat id xay ra tai l<m 88 + 937 QL. 91, Binh My, An Giang vao ngay 22/3/2010 da gay tic nghen giao thong trong nhieu ngay va tinh phai lam dudng tam de giai quyet giao thong tam thdi. Cac giai phap XLl ly vin chUa duac nghien cdu va he thdng hda mot each khoa hoc, mac du mot sd giai phap chdng sat Id duac ap dung nhUng chUa hieu qua d An Giang. Bai bao nay nghien cUu he thdng hoa nhUng giai phap xCf ly sat Id phu hdp vdi dieu kien d An Giang. Cac giai phap xLf ly dien hinh dUdc mo phdng dUng hai phan mem Slope/W va Plaxis 2D. Ket qua nghien cUu khong chi ap dung cho vi tri nghien cUu ma edn cho cac vi tri khac tren dia ban tinh An Giang.
TCfkhda: Sat Id, dodng ven sdng, todng cpe ban, rp da, vai dja ky thuat, cpe xi mang dat.
Abstract: A sliding of embankment at km 88 + 937 on the National Highway No.91 in Binh My - An Giang on March 22nd, 2010 interrupted traffic for several days, and An Giang built a temporary road to reconnect the No.91. Remedial methods have not been thoughtfully investigated even though some local solutions have been applied but is not effective. This paper aims at a system of remedial and stabilized methods that can be appropriately applied in An Giang. Some typical meth- ods were simulated using Slope/W and Plaxis 2D soft- wares. The results suggest that the system of stabilization methods can be practically utilized not only for the research site but for other locations in An Giang.
Keywords: Sliding, highway embankment, river- bank, sheetpile wall, gabion, geotextitle, soil cement column.
1. Gidl THIEU
Vj tri km 88 -i- 937 tren QL. 91 thudc xa Binh My, An Giang da xay ra trupt sau ngay 22/3/2010 doan dai khoang 70 m, rdng 25 m (Hinh 1). Diem sat Id gay t i c nghen giao thdng tren QL. 91 trong nhieu ngay, Tinh phai lam dodng tam song song va each dodng cQ khoang 100 m de giai quyet giao thdng tam thdi [1].
Day la mdt trong nhOng diem sat Id dodng ven sdng dien hinh tren dja ban tinh An Giang. Van nan sat Id nay cd chieu hodng gia tang trong thdi gian g i n day d An Giang [1]. Cac nguyen nhan, nhan td, va cd che gay sat Id da dope nghien cOu va he thdng hda mdt each khoa hpc [2], nhung cac giai phap phdng chdng van choa dope nghien cOu de xuat va he thdng hda.
Bai bao nay nghien cOu va he thdng hda cac giai phap xO ly sat Id phu hdp vdi dieu kien d An Giang. NhOng giai phap xO ly dien hinh trong he thdng giai phap dude md phdng dung hai phan mem Slope/W 2007 va Plaxis 2D.
Hinh 1. Sat Id QL. 91 tai km 88+937 vao ngay 22/3/2010 doan xa Binh My (Anh chup thang 8/2010)
2. HE THONG HOA GIAI PHAP CHONG SAT LCi Nguyen ly cd ban eua eac giai phap xO ly sat 16 la hoac tang sOc chdng e i t , hoac giam Ong s u i t cat trong mai dde, hay dat ca hai cung trong mot giai phap [3]. Mdt he thdng cac giai phap chdng sat Id dope mo ta d Hinh 2. Van de xO ly sat Id tai QL. 91 doan Binh My, An Giang phai dam bao cac yeu cau ve chdng xdi (xdi be mat va xdi d chan), chdng trOdt sau hay mat dn djnh tdng the mai dde do eac nhan td nhO nOdc n g i m , node mat, cac hoat ddng cua con ngOdi, va cau true dja chat gay ra [2]. Cac nhan td nay lam tang Ong s u i t e i t trong mai dde va lam giam sOc chdng eat eua dat d i n den sat Id. NhOng lOc gay trOdt cd the dope giam bang each thay vat lieu nhe hay cOdng dp cao hPn, va thoat node td't hdn de lam giam ap loc nOdc tac dpng len vung mat dn dinh. LOc chdng trOdt cd the dope tang nho thoat node de lam tang cOdng dp khang e i t eua dat, loai bd dia chat yeu hoac d nhOng vung cd nguy ed trOdt, xay dOng nhOng ket eau chdng dd, gia cd dat tai cho, xO ly hda chat de tang cOdng do khang e i t cua dat [3].
3. PHAN TfCH ON DINH 3.1. Phan tfch
Tren cd sd bieu dd he thdng hda cac giai phap chdng sat Id (Hinh 2), cac phOdng phap dien hinh, dai dien cho tOng nhdm phOdng phap dOdc tien hanh lOa ehpn, va phan tfch de ap dung xCr ly sat Id cho vi trf nghien cOu. PhUdng phap 1 dai dien cho nhdm g\k\
phap todng c h i n gdp phan tang cOdng lOc chdng trOdt cho mai dde, sO dung ket eau todng cO van thep Larsen V ket hpp thanh neo (Hinh 3). PhUdng phap 2 dai dien cho nhdm giai phap gia cd, sO dung vai dia Wj
KHOA HOC - CONG NGHE
Tap chi GTVT ii'lUVt
thuat gia cOdng trai thanh tOng idp ket hpp vdi tadng cpe van thep Larsen V chdng xdi chan va chdng tropt sau mai dde, vat lieu d i p dung bao tai eat thoat node va giam dope ap lOc ngang (Hinh 4). PhUdng phap 3 dai dien cho nhdm giai phap thoat node, sO dung ket cau rp da ket hpp vdi vai dja ky thuat gia cOdng, dat nen dope gia cd b i n g cpe xi mang dat dang todng c h i n chdng xdi chan va chdng trOpt sau mai dde, vat lieu d i p dung bao tai cat thoat node va giam ap lOc ngang (Hinh 5). PhUdng an 4 dai dien cho nhdm giai phap lam thoai va danh cap mai dd'c, sO dung bao tai eat san lap lam thoai va danh cap mai dde (Hinh 6).
Giai phap nay da dope dja phOdng sO dung de xO ly khan cap sau khi sat 16 xay ra [4]. Qua trinh phan tich sO dung moc node t h i p nhat Ijch sO nam 1990 - 0,73 m (sd lieu do Trung tam KTTV An Giang eung cap), hoat tai xe 30 T dope qui ddi theo [5] la 16 kN/m^, hoat tai ngOdi di bd la 3 kN/m^, va tai trpng nha dan la 12 kN/m^ Sd lieu dja chat dapc tdng hdp d Bang 1, cae thdng sd vat lieu gia cOdng dupe trinh bay d Bang 2.
1 ~~, , 10m
N H A 1
12m ftm
1 1 i i 1 i ' 1 i 1 • 1 : ' 1 U 1 l.l
/ \ ^ ^ S 3 ®S / \ H)"®
C o c n e o B T C T / 0,3 X 0,3 d a i .Llm /
\ T b a n h Deof.50
\ L.S = 2,52m
/ \ / \
'. I.!im ' ? Im
Tifcfug ci^ L a r s e n V d i i 2 9 m
~,
Hinh 3. PhUdng phap (PP) 1 st? dung ket cau tudng coc van thep cd 1 tang neo
Um , 5m
L:im thom mai doc
/ 3ao lai Lai tao mai in > . I Danh cap inai clue
N H A
1.1 l l I
M M ' Tam BT d\\c szn 1 1 ij 1 i-ii ^
'-.w . y — a - .y .jjji li^- \^->^
" '"" • -SS' ,.775 0 CS'
V;JL lieu d a p b ^ o g bao lai ca'l
Tu'dus cu' L a r s e n V dai 25m
/ x''-"°
'4.8m — « S B -
~~i.
1
1 J Giai phap giam ^ , TGni BT due U n
/I lire eay Iruat i \ Hao vc be mat mai cloc / , •, -
( ' -^ —• p Da npe (do roi. xep khan. \ a v ) TJiam ro da
i Phiip C'hong Sal Lo
'I'hoal nutVe mat • Tao ranh. iiurLrng thoat niroc - Xir ly eac \cl niri be mat
, Onii thoiit iiiroc nsjam:
/ Su diiny \ a l IICLI diip eo kha niinu Thoai ntrae nyam ! Ihual nmVc (d;i, c(i\. hao lai eal)
* Sir duny kel cau cu kha nang Ur ihoai nirae (lironsi chan ro da) lirong liniig I'l'c' iTrong he lung
\ f Ouii phap tang
[ lire khang inrol [ T u a n g chan i "1 irong ban (rong luc ' ^'^'"^ ' ' " - ' l\ I LroiiLi coc \ a n Ihcp 1 firoim eoc iian
\ ^ "Iifony B I C r D i l l .
" Tirong on dinh LO hoc ( M S b I
\ ai dia k\ Uiuat - Sir dunu vat lieu DKJ
LiriVi clia kC thuat
Hinh 4. PP. 2 SLf dung VDKTgia cudng mai doc ket hap tudng cgc
van thep chdng xdi chan va trugt sau
lOm 12m I 5m
Ta'ni BT diJc srfn
NHA
Tifdng ro di5 r a o
?m, rong 401
Tirefng coc XM dat di^y 3m, dAi 19,5ra
- Lam eirniz dai
Hinh 5. PP. 3 SLf dung ket cau rg da thoat nude, VDKT gia cudng,
ket hdp tudng cgc XM dat chdng xdi chan va trudt sau
Hinh 2. He thdng cac giai phap chdng sat Id phu hdp vdi dieu kien 6 An Giang [3]
Bang 1. Sd lieu dia chat tai vj tri sat id tai km 88+937 tren QL. 91
T g n l o p S e t d e o c u n g
B u n s e t S e t n u a c u n g
B e d a y ( m ) 5 , 5 1 8 6 , 5
S o b u a S P T
9 1 2 0
y ( k N / m ^ )
1 8 , 7 1 5 , 5 1 9
( k N / m ^ ) 2 5 , 3
6 , 8 3 0 , 1
(cJ<3) 1 2 , 4 6 1 7
c' ( k N / m ^ )
2 5 , 3 1 6 , 3 3 0 , 1
<P' ( d p ) 1 2 , 4 2 0 . 2 1 7
Bang 2. Thdng sd cac vat lieu gia cudng tang kha nang chdng trugt
T S n v a t l i S u C u ' L a r s e n V [ 6 )
C o c X M d a t [ 7 ] B a o t a i c a t R o t h e p m a k e m b o c P V C
y ( k N / m ^ )
19 1 7 2 3 , 5
c ( k N / m ^ )
7 0 6 0 , 1 4 0
<P ( 3 6 )
3 0 4 5 4 0
E A (kN/m) 2 5 4 . 1 0 "
El (kN m^/m)
101886
Hinh 6. PP. 4 SLfdung bao tai cat san lap lam thoai mai dd'c
3.2. Ket qua
Ket qua phan tieh dn djnh cho cae phoong phap dOde the hien d Bang 3. Md hinh phan tieh tieu bieu cho cac md phdng dOng phan mem Slope/W the hien d Hinh 7 Hinh 8 the hien md hinh tieu bieu cho cac md phdng bang FEM dung phan mem Plaxis 2D.
HI
KHOA HOC CONG NGHEBang 3. Ket qua phan tich cac phUdng phap nghien cUu
Phu'cing phap
PP 1 Tuong coc van thep co 1 tang neo.
PP 2' Vai dia ky thuat gia cuong ket hop v6i tucSng coc van
PP 3: Ket cau ro da ket hop tuong coc xi mang dat.
PP 4: Su dung bao tai cat san lap tao mai lam thoai va danh cap mai doc.
He so on dinh tong the (FS) SlopeAA/
1,59 1,48 1,5
Plaxis 1,66 1,46 1,44 On dinh truot 1,66
On dinh lat: 4.72 0,69 ^ 1
Moment Ion nhat, M„^
(kN m) 269 249
Luc neo.
R (kN) 127
Distance (m)
Hinh 7. Md hinh xac dinh he sd dn dinh dung Slope/W 2007
Hinh 8. Md hinh xac dinh he sd dn dinh bang FEM dung phan mem Plaxis 2D
4. THAO LUAN
4.1. Giai phap tiidng chan
Theo [3], giai phap todng chan dapc sO dung de tang cOdng kha nang chdng trapt cija mai dde, chdng lai ap loc ngang cua dat. Cae dang todng chan dat nho todng chan be tdng, todng chan BTCT, todng chan rp da, va todng cpe ban. Hien nay, todng cpe ban (BTCT hay thep, [8]) (TCB) thodng dope sO dung nhieu trong eac cdng trinh giao thdng, thuy Ipi, va cang bien. Uu diem eua TCB la kha nang ehju lOe Idn, khdng ehiem dung dien tich Idng sdng, chdng dope xdi Id, trOpt sau, va dam bao my quan cho eac cdng trinh xay dOng nhOng gia thanh xay dOng cao nhat trong tat ca eac giai phap chdng sat Id. Khi sO dung todng cpe van thep gia cd bd sdng (PhOdng an 1, Hinh 3), he sd dn djnh tinh theo Slope/W la 1,59 va theo Plaxis 2D la 1,66 (Bang 3), dat yeu eau [5]. Do dd, giai phap nay chi nen dupe sO dung d nhOng ndi quan trpng nhu eac trung tam hanh chinh trong tinh.
4.2. Gidi phap gia cd mai doc
Ky thuat gia ed mai dde da dope sO dung tO rat lau trong Ijch sO [3]. Vdi cac cdng trinh d i p cao nho dodng vao cau hay de dap nguy cd mat dn djnh cao. Cae vat lieu dja ky thuat cd kha nang ehju keo td't dupe dat theo phuong cua chju keo, giup gia codng, bd sung
nhOde diem chju keo kem cua dat. LOc keo dope huy dpng thdng qua lOc ma sat d mat tiep xuc vdi dat. Khi cd chuyen vj tOdng ddi, chung gop phan lam giam lOc gay trOdt, ddng thdi lam tang loc chdng trOdt trong dat va tang dp dn dinh cua cdng trinh [9]. Hdn nOa, be mat mai dd'c phai dope bao ve de giO cho dat dap khdng bj xdi Id do tac ddng cua cac yeu td mdi trodng [11]. Khi sCr dung vai dja ky thuat ket hdp vdi cac ket cau khac (Hinh 4), he sd dn dinh theo Slope/W la 1,48 va theo Plaxis 2D la 1,46 (Bang 3). Vdi vai dja ky thuat, mai dde ed the dap 1:1, han che ehiem dung dien tich Idng sdng. Phoong phap nay nhin chung cd nhieu Ou diem va la phOdng phap phdng chdng sat Id hieu qua.
4.3. Giai phap thoat nUdc
Ddi vdi cac cdng trinh ven sdng nhO nen dOdng va de dap, qua trinh giam dot ngdt mOc node sdng luon gay nguy hiem cho sO on djnh tdng the do node trong cac Id rdng cua dat khdng kjp thoat tao nen lOc tham [3]. Vi vay, giai phap thoat nude phai dope quan tam hang dau. Mdt sd bien phap thoat node nhO lap dat cac dng thoat node, sO dung vat lieu dap cd kha nang thoat node td't (da, cat, bao tai cat) hay xay dong cac ket cau cd kha nang to thoat node nhO tOdng chan rg da. Vdi kha nang thoat node td't, ket cau rp da nen dope sO dung giup giO cho mOc node ngam trong dat dap sau rp da ludn bang vdi node mat [10]. Hdn nOfa, gia thanh xay dOng ket cau rp da re hdn rat nhieu so vdi cac ket eau khac do it phai bao dOdng, thi cdng ddn gian, khdng ddi hdi thd lanh nghe. Rp da con la mdt ket eau trpng lOe ed kha nang ehju dope lOc day ngang cua dat, chdng lai tac ddng cua xdi do dong chay gay ra. Vdi ket cau rp da lam todng chan, vat lieu dap la bao tai cat thoat node ket hpp vdi tOdng epc xi mang dat gia cd nen chdng lai xdi chan va trOdt sau mai dde (PP 3, Hinh 5), he sd dn tinh theo Slope/W la 1,5 va Plaxis 2D la 1,44 (Bang 3). PP 3 cd kha nang thoat node td't nen cd the chdng dope sii giam dot ngdt cua mOc node sdng cung nhO nhOng anh hodng do bien ddi khi hau. Gia cd nen dat bang todng cpe dat xi mang vOa giO cho ket cau rp da dOdc dn djnh, vOa chdng xdi sau d chan do tac dpng cija ddng chay d Idp dat yeu. PhOdng phap nay cung dOdc Vien Khoa hpc Thuy Idi mien Nam kien nghi sO dung de chdng xdi Id bd sdng d huyen Nha Be, TP HOM [11]. Giai phap nay it ehiem dung dien tieh Idng sdng, rat than thien vdi mdi trodng, va hieu qua.
4.4. Giai phap lam thoai mai doc ||
Thoai mai dd'c thodng dope sO dung de tang cOdng so dn djnh cho mai dde [3]. Giai phap nay da dOdc dja phOdng thoe hien de xO ly sat Id khan cap tai vi tri nghien cOu [4]. Khi sO dung bao tai eat san lap lam thoai mai dde vdi he sd mai 1:3 (Hinh 6), he sd dn djnh 0,69 (Bang 3). Vi vay, giai phap nay chi gia co tam thdi, lap hd xdi, va day ddng chay chinh ra xa bd han che xdi 16 mai dd'c. Tuy nhien, giai phap nay lam thu hep, thay ddi ddng chay dSn den gay xdi Id 6 nhOng khu vOc Ian can ve lau dai. Giai phap nay khdng hieu qua va nen
han che sO dung. ^xem tiep trang 36),
KHOA HOC CONG NGHE
Tau hoat ddng tren nen cdng dn djnh, khdng bi nghieng ngang, nghieng doe. Thanh phan lae nang tau dam bao nang tau len khdi mat dat vdi khoang each nha yeu eau ly thuyet dat ra.
Tfnh an lai cua tau hoat dpng tdt, dam bao tau quay trd tdt khi hoat dpng.
Vay tau dam bao dp ben khdng bi rd khf va mai mdn lam giam ap sua't khi tau dang hoat dpng, chdng td phan tinh toan thiet ke vay dam bao yeu cau dat ra.
Tau dang chay tren mat dudng Tau dang quay trd
Hinh 10: Thd chay tren mat dat
Sau khi chay thd nghiem nhieu Ian tren mat nadc nhan dapc mdt sd ket qua sau (hinh 11):
Tau chuyen dpng on djnh tren mat nadc.
Tau khdng bj nghieng ngang, nghieng dpc khi dang hoat dpng.
Tde dp eua tau dap dng nha yeu cau ly thuyet dat ra.
Tfnh an lai, tfnh quay trd eua tau dam bao eho tau chay dn djnh.
Hinh 11: Tau dang chay tren mat nude 5. THAO LUAN KET QUA
Ket qua tfnh toan, thiet ke va che tao thd nghiem nhan thay md hinh tau dem khf da che tao hoat dpng dn dinh, dat dapc cac yeu eau dat ra va dam bao dUdc cae tfnh nang hang hai can thiet ddi vdi tau dem khi.
Dac biet, he thdng dpng lac, he thdng dieu khien tu dpng dapc thiet ke va bd trf phu hpp lam tang dp tin cay eho tau khi dang hoat dpng, he thdng vay khf dam bao nang tau va tao ap sua't ben trong dn djnh khi tau dang hoat dpng trong dieu kien tren mat dat va dadi nadc, do dd ed the la ed sd quan trpng de che tao tau that •
TAI LIEU THAM KHAO
[1]. Liang Yun, Alan Bliault. Theory and Design ot Air Cushion Craft, ArnoldPublications, (2000).
[2]. Universal Hovercraft Construction and Opera- tion, (2004).
GIAI
P H A PXUf LY SAT LOf.
(Tiep theo trang 14)
5. KET LUAN
Nghien cdu nay thae hien eac md phdng vj trf sat Id tai km 88+937 tren QL. 91 Binh My, An Giang sd dung eac sd lieu do nhdm nghien cdu trae tiep khao sat do dac. Hai phan mem Slope/W va Plaxis 2D dapc sd dung cho cae md phdng nay. Ket qua nghien cdu eho phep rut ra eac ket luan sau:
(1) Cac giai phap chdng sat Id han che thu hep Idng sdng: tadng c h i n , gia cd mai dde bang eac vat lieu dia ky thuat.
(2) Nhdng giai phap chdng xdi chan va trapt sau:
tadng cpe ban hay tudng cpe dat gia ed xi mang.
(3) Cae giai phap thoat nadc mai dde: sd dung vat lieu d i p cd kha nang thoat nadc tdt (da, eat, bao tai cat), tudng chan rp da.
(4) Nhdng giai phap bao ve mai dde: sd dung tam be tdng xi mang due s i n , tham da hay da hoc (dd rdi, xep khan, xay) •
TAI LIEU THAM KHAO
[1] Uy ban nhan dan tinh An Giang (2010), Bao eao tinh hinh sat Id tren dia ban tinh An Giang sd 84/BC-UBND ngay 17/8/2010.
[2] Le Xuan Viet va Tran Nguyin Hoang Hung (2011), Sat Id dudng ven sdng tren dat yeu OL. 91 doan Binh My, An Giang, Tap chf Giao thdng van tai, sd thang 6/2011.
[3] Abramson L. W., Lee T. S., Sharma S. and Boyce G. M. (2002), Slope Stability and Stabilization
methods, John Wiley and Sons, Inc., New York, 712 pp [4] Cong ty Co phan TU van va Dau ta Phat trien An Giang (2010), Ban ve thiet ke thi cdng cdng trinh Xd ly khan cap sat Id QL. 91 - km 88 -h 937 xa Binh My, huyen Chau Phu, An Giang.
[5] Bp Giao thong van tai (2000), Quy trinh kfiao sat thiet ke nen dUdng d td dap tren dat yeu 22TCN 262 2000 (Ban hanh kem theo Quyet dinh so
1398/QD-BGTVT ngay 01/6/2000 cua Bd trUdng Bo Giao thdng van tai).
[6] Bp Giao thong van tai (1994), Cdng trinh ben cang sdng - Tieu chuan thiet ke 22TCN 219 - 1994
[7] Tran Xuan Thp va Tran Thanh Trung (2009), Tinh toan dn dinh cdng trinh ben cau tau tren nen dat yeu, Ky yeu Hdi nghj Khoa hpc va Cdng nghe Ian thiJ
11 - Khoa Ky thuat xay dang - Tradng Dai hpc Bach k h o a T P HCM, trang 44 - 5 1 .
[8] Pham Van Giap, Nguyin HCfu Dau va Nguyin Ngpc Hue (2008), Cdng trinh ben cang, NXB Xay dang. Ha Npi, 379 trang.
[9] Cao Ngpc Hai (2001), Thiet ke vai dja ky thuat va bac tham, Tradng Dai hpc Bach khoa TP. HCM, Khoa Ky thuat xay dang, 82 trang.
[10] N g u y i n Khanh TUdng (2001), Ro da trong cae cdng trinh Thuy Idi - Giao thdng xay dUng, NXB Xay dang. Ha Ndi, 101 trang.
[11] Dinh Cong S^n va Le Manh HCing (2005), Bao cao tdng ket dU an td ehde nghien cdu giai phap khic phuc sat Id bd sdng tren dia ban huyen Nha Be, Vien Khoa hpc Thuy Ipi Mien Nam, Bp Ndng nghiep va Phat trien ndng thdn, 146 trang.