KHOA HOC - C O N G N G H £ l l l l l
NGHIEN COU GIAI PHAP ON DjNH TA LUY
VA KIEM TOAN ON DjNH TA LUY BANG PHAN MEM GEOSLOPE CHO DUdNG TUAN TRA BIEN Gldi TJNH SON LA
Tom tit: Bai bao trinh bdy phwang phdp 6n dinh mdi ta luy trdn dw&ng tuin tra bien giai tren dja ban Tinh San La bSing bi$n phdp cit ca, xep ro dd. Cfng dyng phan mem GeoSiope dwa ra moi quan h$ gida h0 s6 6n djnh K, chieu cao cSt ca h vd d0 ddc 1/m cua mai ta luy tie dd kiim todn duxK Sn djnh mai ta luy thidt kd ho$c /t/a chpn d u p c gid tn 1/m dam bao mdi ddc Sn djnh, nhSm h^n che hien trang sut f m p f xay ra.
Tie khoa: Ta luy, Geoslope, San La, dn djnh mai doc, sut trwot, rQ dd.
Abstract: This article presents methods of stabilizing the sloping roof on border patrol by means of cutting muscle, stone glove.
GeoSiope software application provides a relationship between the stability coefficient K, the height hierarchy h and the angle 1/m of the slope roof from which the sloping roof is audited as well as the value choice 1/m assures The steep slope, in order to limit the sliding state occurs.
Keywords: GeoSiope. coefficient, slipping,
gabion. .
1. D A T VAN D £ N G H I & N cCru
Mai doc ta luy du'O'ng co vai trd h^t si>c quan trpng dam bao ch^t lu'png cong trinh du'dng 6 tfi. Du-ai tac dung dong thai cua trpng lu'png bdn than, cac y^u t6 tir nhien, ho^t dpng cua con ngu'O'l co the lam mat on djnh mai d6c dan den hu- hai cong trinh du'O'ng 6 to, gay nguy htem tfnh mang ngu'di tham gia giao thong, pha v o canh quan thien nhien, thiet hgi kinh te... Vi v ^ y thiet ke tinh toan on djnh mai doc ta luy Id ySu c^u CO y nghTa khoa hpc va t h y c t i l n (theo TCVN 4054-05 v d i nen d^o vd n i n dap co chieu cao Idn ho'n 12m bat bupc phdi kiem toan 6n djnh mdi doc). Mat khac, vipc tinh to^n 6n djnh mdt doc giUp viec thiet k l mai doc ta luy hpp ly gdp phan lam gidm chi phi x§y d y n g cong trinh cung nhu hgn c h l s y sut tru'pt Taluy nen du'dng tu^n tra bien gidi (TTBG) du'di tac dpng cua cdc yeu to t y nhien.
Tuy nhien, viec tinh toan on djnh mai d6c ta luy la mot bdi toan phdc tap co kh6i l y p n g tinh toan Idn neu xet
NGUYEN THI MINH H A N G N G U Y £ N THANH SANG
H O A N G Q U d C LONG Vi§n Ky thugt Cong trinh dgc bipt
Hpc vien Ky thu^t Qudn s y T6NG THANH OAT
Ldp Cau du'dng 12 Hpc vien Ky thugt Quan s y
tren todn bp chieu dai t u y i n du'dng TTBG tren ffia bdn Tinh So-n La. D y a vao nguyen I;? can bang gidi hgn, mOt so p h u c n g phap tinh toan cOa Fellenius, Bishop,... da danh gia on djnh mai d i e ta luy qua hp s6 I n djnh nho nhat (K^,J cua mat tru'pt nguy h i l m . De tim d y p c mdt trupt nguy hiem cdc phu'ong phdp nay phai gia djnh n h i l u mgt trupt khdc nhau, tfnh du'pc cdc hp so on dinh tuang u n g vdi cdc mgt trupt gta djnh dd. D y a vao gia trj cCia cac hp so on djnh, xac djnh d u p c hp so on djnh nho nhat K^|„. De giam thdi gian xdc djnh K d y a theo kinh nghigm tinh todn on djnh cua vo so cac mdi d i e ngudi ta cung cd mpt so each tim ra d u d n g quy tich tdm tru-pt nguy hiem nhung khoi lupng tfnh toan van Idn vd k i t qua khong chfnh xac.
Ngdy nay vi^c sit dung may tinh 6k giai q u y l t bai toan on djnh rat p h i b i l n kem theo dd Id cdc p h i n m i m SCP dyng d u p c xdy d y n g tren nguyen Ij? cDa Fellenius, Bishop... Viec giai q u y l t bdi todn tfnh on djnh mdi d i e ta luy nhanh han vd chinh xac han.
GeoSiope la phan m i m tfnh on djnh mdi d i e cQa Canada da d u p c rat n h i l u n u d c tren the gidi sir dgng vd du-pc ddnh gia cao. GeoSiope cho phep tfnh toan mai doc trong n h i l u dieu ki^n c6 t h l xay ra trong t h y c t l n h u xet den tu-dng chdn, neo trong dat, vat dja ky thugt, d i t khong dong nhat, dat bao hao nu'dc, d i t khong bao hda nudc...
2. HIEN TRANG, NGUYEN N H A N SAT L d N^N DU'O'NG T U A N TRA BI^N GI&I T I N H S O N LA Tren dja bdn cdc tinh San La, h# thong d u d n g tuan tra biSn gidi vdi chieu ddi 173km, c6 ^ nghTa dgc bi^t quan trpng trpng xdy dyng va bdo vp T 6 quoc. Ndm d viing ndi cao, each xa khu dan cu', dja hinh tuyen d u d n g t u a n g doi phU-c tgp, dogn gidp bidn gidi chu yeu la niii cao v u c sau n h i l u dogn dja hinh thay d6i dot ngOt tip tren cao x u i n g thap, dp doc ngang va dO
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d i e dpc rat Idn, hipn da cd n h i l u vi tri sat sut ta luy d u a n g do dja chat phfa tren la Idp dat khdng on djnh, phia d u d i la ldp ddt da rdi rgc khi bj nggm n u d c gay sut truat hogc Idp da phong hda co the nam nghieng 35-500 ndn d l mdt on djnh, Ngoai ra, tren dinh ta luy d u a n g hien trgng hinh thdnh khe tu thuy cd hidn t u a n g xdi vdo miia mu'a gdy djch chuyen mai ta luy nguy c a sgt Id rat cao.
Hinh 1. Diem sat la doan Km46-H33-:-Km46+148 thuoc tuyen DTTBG mdc C8- D1 Vdi hipn trang trSn, nhiem vy phdng, chong khdc phyc sut tru'pt la rat quan trpng vd cdn thiet. Trong qud trinh khai thdc cdng trinh, Ban quan ly d y an 47 da cd gidt phdp hot sut, bien phap nay khdng hidu qua v) den miia m u a hang nam Igi xuat hipn cac diem syt tru-pt mdi hoac t i l p tuc sut tru'pt cdc diem da xdy ra cdc nam tru'de. Do vay, van d l dat ra Id can CO giai phdp gia co tgi mpt sd dogn cd chieu eao dao d i p Idn, dja c h i t dat da rdi rgc phong hda kem on djnh n h l m bao dam rang n i n du'dng TTBG on djnh va cong trinh khai thac d u a c binh thudng theo chifc nang dam bao nhipm vy tuan tra ciia B6 dpi Bidn phdng du-pc thugn Ipi, cung n h u ket hpp giao thdng dan sinh, phat t r i l n kinh te xa hpi cua nhdn dan tren dja bdn.
3. CAC BIEN P H A P O N DjNH TA LUY DU'ONG TUAN TRA BI£N GI&I TINH SON LA
Dgc d i l m cua tuyen d u d n g tuan tra tinh S a n La co e h i l u eao mai ta luy d u a n g Idn, hinh dgng ta luy bat lpi, dja ehat dat da phong hda kem on djnh, Khi mua trpng lupng dat da tang len n h i l u dong thai kha nang chong c l t cua dat da giam, d i n den mat d i e mat on dinh. Chinh vl vgy, vi#c t h i l t ke va tht edng
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dgng mdt c l t hpp ly la rat can t h i l t n h l m dam bao cho n i n d u d n g on djnh. Giai phap cat c a bgt mdi thudng d u p c lya chpn do dan gidn, logi bd dupc phan Idn khoi gdy toppt va ehi phi khdng Idn. Chieu cao mai taluy ddo d u p e cat c a phu hp'p vdi dieu ki?n dja chat dat la 8m vd 12m khi dja chat nen du'dng la da. D i l n hinh trSn dudng TTBG dogn moc 06- 0 8 . m i c C8-D1 da dup-e t h i l t ke va thi cdng cd trie ngang dien hinh the hipn nhu tren hinh 2:
Duong thiet ke
Hinh 2. Bi$n phap cat ca on dinh mai ta luy duong Trong do:
- C h i l u cao giiia cdc c a h la 8m hogc 12m;
- C h i l u rpng c a b Id 3 m ;
- Mgt c a nghieng 2 % vao trong k i t hpp lam ranli thoat n u d c ;
- D d d i e mdi ta luy 1/m d u p c thiet ke vd kilm toan dam bao on djnh.
Tuy nhien, do dja hinh tuyen d u d n g di qua phi^c tap, chdnh cao Idn, nen gidi phdp t h i l t ke c l t co co ehieu cao mdi Taluy Idn se dan d i n bipn phdp thi cdng khdng thuan Ip'i, k h l i lupng thi cdng ldn, chi phf xay d y n g tuyen d u d n g cao. Do v§y, nhung vj trf nay thudng sir dung glal phap cat c a k i t hap tudng chan, trong do su dung p h i bien la dgng tudng chan mem rp da. K i t cau t u d n g chan bang ro da bao gdm cac rp da djnh hinh d u a c lien ket vdi nhau qua lifin k i t budc va cd neo thdp hinh vdi n i n dat nham tgo s y I n djnh cho k i t c l u t u d n g chan ndi rieng vd cOa todn bO Taluy n i n d u d n g ndi chung. T u d n g chdn ro dd la mpt glal phdp dan gidn nhung c6 hi^u qud cao, cd kha nang ehju d u p c s y tdc dpng khdc nghipt cOa mdi trudng vd dieu kien bien dgng Idn. Ben cgnh 66, k i t cau t u d n g chan rp da ed kha nang thoat nudc tot, khong gay ra dp l y c thuy tTnh phia trong k i t cau t u d n g ehan, de thi cdng, chi phi xay d y n g thap rat phil hp'p vdi s u i t dau t u cdc tuyen d u d n g m i l n nCii ndi ehung, cung n h u t u y i n d u d n g TTBG ndi ridng.
Giai phap k i t hpp c l t e a va t u d n g ehan rp dd tren d u d n g TTBG dogn tuyen m l e C6-C8 va C8-D1 thupc dja ban tinh S a n La dup'c the hidn tren mat cat ngang dien hinh n h u hinh 3.
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Hinh 3. Bidn phdp cSt ca kdt hap ro da on djnh mai ta luy dwang
4. O'NG DUNG P H A N M ^ M GEOSLOPE T I N H TOAN 6 N OINH MAI D6C TALUY N^N DU-^NG TTBG
GeoSiope la phan mem phan tich on djnh cua mdi d i e theo cdc ly thuyet tinh todn ciia Bishop, Ordinary, Jabu, Spencer, Morgenstern-Priee. Phan mem giai d u p c nhu'ng bai toan on djnh trong dieu kien Taluy cd dja chat dat da khong dong nhdt v d i mat trupt b i t ky, chuang trinh t y ddng tim ra mgt t n j p t nguy hiem nhat de t h i l t k l gtat phap on dinh cho phii hpp. Ddy Id trudng hp-p tong quat vd thudng gap n h i t trong thyc te. D l ddm bdo mat d i e on dinh thi hp so on djnh nho n h i t (K^^J eOa mat trupt nguy hiem co gid tri tip 1.1 -:-1.5.
Xet trudng hap tong quat khi khoi d i t co mat trupt dgng cung trdn theo ly t h u y l t cua Bishop, khi dd cac lyc tae dyng vao khoi d i t dup'c the hipn n h u hinh 4 .
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Hinh 4. Cdc ii^ tac di^ng len m$t trwot tru trdn theo Bishop
Trong dd:
P: Trpng lup'ng cua manh trupt N: L y c phdp t u y i n tgi day manh truat S: L y c e l t tai ddy manh trupt
E,, Eji L y c t u a n g tdc theo phuang ngang giira cac mat t r u p t
X,, X j ! Lye t u a n g tac theo phuang t h i n g dimg giti-a cac mgt t r u p t
W: L y c dpng dat di qua trpng tam manh trupt R: Bdn kinh mgt trupt tru trdn
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Trong phgm vi bai bao, nhdm tac gia dung GeoSiope phdn tich on djnh eua mai doc cho mat cat t h i l t k l nguy h i l m n h i t (chieu cao mdi ta luy Idn nhat, dat cd cudng dd kem nhat) dai dien cho mpt so dogn tren d u d n g tuan tra bien gidi vdi hp so on dinh yeu eau Ky. = 1 .2
So lieu dau vao: Do dgc mgt e l t t y nhien cua mai doc theo thye t l tren t u y i n dudng, khoan l l y mdu, thf nghiem ede mau d i t trong phdng thi nghidm de cd cdc thdng so can thiet gom: L y c dinh C, gdc ndi ma sdt (f), trpng lupng the tfch y (lay d trgng thai bao hda nudc).
Tien hanh thiet k l on djnh mat d i e ta luy theo gidl phap c l t c a va e l t ea k i t hpp tudng chan rp dd. S l cff theo mat e l t ngang thiet ke. Dp doc mat ta luy 1/m CO t h l nhdn ede gid tn 1/0.5;1/0.75;1/1 0. Rp dd t h i l t k l theo djnh hinh.
Nhdp so lieu eho mat c l t mai doc thiet k l , chu y t u d n g c h i n rp dd d u p e khai bdo n h u mpt thanh phan cua mat eat cd eudng dp ehong cat tdn, l l y l y c dfnh bang 100, gdc not ma sat 35°, trpng lupng the tfeh 14,7KN/m^. Thiet lap chuang trinh tinh toan va b i l u thl k i t qua tfnh.
K i t qua can thu d u p c : Od thj the hien moi quan he giii'a hp so on dinh K, chieu eao gidt cap h va dp d i e cua mdi ta luy 1/m. D y a vdo m l i quan he dd cho phep ta lya ehon d u a c gid tn 1/m n h l m dam bao mai Taluy phii hp'p vdi he so on djnh yeu cau K^^
hogc kiem todn d u a c mipc dp on djnh cua mdi ddc t h i l t ke da chpn.
Nhdm tdc gid lya ehpn 3 doan t u y i n dien hinh ed mdi doc cao, dja chat phuc tgp, da xay ra syt trupt va t h i l t ke giai phdp c h l n g sgt Id Taluy nen d u d n g tren t u y i n d u d n g TTBG tTnh San La, dogn moc C6- C 8 v a m 6 c C 8 - D 1 .
4 . 1 . Tuyen thupc doan m o c 0 6 - 0 8 tiP Km18+34 -:- Km18+60
Mat c l t dgi dipn tai d i l m sgt Id ndy duae t h l hten nhu hinh 5 va c6 dgc d i l m dja chat vdi tfnh c h i t ea ly khi dat dd bdo hda n u d c n h u sau:
Lap d a t
L d p 6k 1 L o p dat 2 L&p dat 3 lap d^t 4 L6p dat 5
Chieu s a i l h ( m )
0.5 1 5 5 N i n f l f i
D u n g t r o n g y {KNIm^)
13.2 16,64 19-62 22.32 25 43
L i ^ d i n h do-n v j C
(kPa) 6 8 20 32 23
Goc n^i m a s a t i|>
(do) 8°
i r 19=02' 5 6 ' 53' 71° 93'
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Vdi mat cat da xde djnh va dieu kien dja ehat trdn, nhdm tdc gid sif dung phan m i m GeoSiope d l tinh todn vd k i l m tra on dinh khi thay doi dp doc mdi ta luy 1/m se xdc djnh d u p c hd so on djnh K t u a n g ifng, tif do lgp do thj t h l hien m l i quan h^ giu'a dp d i e mai taluy va h^ so on djnh n h u ket qud tren hinh 5.
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Hinh 6. KSt qud tinh todn on dinh mdi taluy cho diem Dl -G3
Hinh 5. Ket qua tinh toan on dinh mai taluy cho diim D9 - G2
Tir k i t qua tinh todn d tren, vdi he s l on djnh yeu cau Id K^^ = 1.2, thl dO d i e mat ta luy t h i l t k l 1/m phdi nhd han 1/0.6. Trong phuang an t h i l t k l , thudng l y a chpn dp d i e mdi ta luy la 1/0.75.
4.2. Tuyin thudc doan moc 0 6 - 0 8 t i l ' Km33+424 -:-Km33+442 '
Mat cat dgi dign tgi diem sgt Id nay d u p c the hign nhu hinh 6 vd cd dgc diem dja chat vdi tinh chat ca ly khi dat da bao hda n u d c nhu sau:
Tif k i t qua tinh toan d trdn, vdi h f so on djnh ydu eau la K^ = 1.2, thi dp doe mai ta luy thilt ke 1/m phai nhd han 1/0.44. Trong phuang an thilt ke, thudng lya chpn dp doc mai ta luy Id 1/0.5.
4.3. Tuyin thuoc dogn moc 0 8 - D1 tip Km40+26 -:- Km40+39
Mat eat dai dien tgi d i l m sgt Id ndy d u p c the hien n h u hinh 6 vd ed dac d i l m dja chat vdi tinh chit cff ly khi d i t dd bao hda n u d c n h u sau.
L&p Qk
L&p ak 1 Ldp ak 2 Ldp 6k 3 Ldp 6k 4 L6p dit 5
Chl^u sdu h{m)
0,5 1 5 8 NendS
Dung trpng y (KN/m=) 14.2 16,64 19.62 22.32 25.43
LM'C dinh darn vi C (kPa)
S 12 20 32 35
Gdc n$i ma sat <{•
10°
13°
19=20' 56° 53' 71° 93' Vdi mat c l t da xdc djnh vd d i l u ki$n dja c h i t tren, nhdm tac gia s u dung phan m i m GeoSiope de tfnh toan va kiem tra I n djnh, tU' do ldp d l thj the hign mol quan he giira dp d i e mdi taluy vd h$ s6 on djnh nhu k i t qua trdn hinh 6.
LA'P dat
Ldp dat 1 Ldp dat 2 Ldp dat 3 Ldp dat 4 Ldp d^t 5
Chieu sdu h(m)
1 2 5 8 Nen da
Dung trpng y (KN/m^) 12,2
15 20 25 35
L i ^ dinh do^ viC
(kPa) 5.4
7 20 32 35
Goc n^i ma sit ^
m
6" 10° 20° 25' 56° 53' 71° 93' V d i mgt c l t da xdc djnh va dieu kipn dja c h i t tren, nhdm tdc gid s u dyng p h i n mem GepSlope d l tinh toan va k i l m tra on djnh khi thay d l i dd d i e mdi ta luy 1/m se xae djnh d u p c hp s6 on dinh K tuong ung, ttr dd ldp d l thj the hign m l i quan hp giO'a do doc mdi Taluy vd h6 so I n djnh n h u k i t qud trdn hinh 7.mi^m
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Hinh 7. Kdt qua tinh toan on djnh mai taluy cho diim Dl - Gl
Tir k i t qua tinh toan d tren, vdi he so on djnh yeu cau la IC. = 1.2, thi dp doc mdi ta luy t h i l t k l 1/m phai nhd han 1/0.7. Trong phuang an thiet k l , thudng lya chpn dp doc mdi ta luy Id 1/0.75.
Trdn ddy la mdt s l vi du s u dyng GeoSiope de tinh todn hd s l I n djnh cua mai doc ta luy. D y a vao k i t qua tinh toan irng vdi hp so on djnh yeu c l u K^^ ta xde djnh d u a c dp doc mai ta luy c i n t h i l t k l hoge xde djnh dup'c he so on djnh K cua mdi doc t h i l t k l . Cd t h l dp dung k i t qua tinh todn cho cdc dogn t u a n g t y trdn t u y i n d u d n g .
5. Ktl LUAN, KI^N NGHj
Bat bao da lam rd t h y c trang sat Id taluy nen d u d n g , phan tieh nguyen nhan vd d l x u l t mpt s6 gidi phdp nham dam bao on dinh Ta luy n i n d u d n g TTBG, n h u t h i l t k l dd d i e mai taluy phii hpp, t h i l t ke eat c a mat taluy vdi c h i l u cao hp'p ly, k i t hpp giai phap t u d n g c h i n rp da v d i cat c a mdi taluy d nhu'ng dogn tuyen cd dia hinh phirc tgp, dd doc t y nhien Idn.
Nhdm tae gia sir dung phan mem phan tich dja ky thugt ehuydn dung GeoSiope de giai bai todn n i n dudng ed dja chat khdng dong n h i t , nen bao hda nudc, mai d i e thiet ke phuc hpp (eac dp doc khdc nhau, chieu cao mdi taluy Idn va thay doi) phii hap vdi dieu kien thyc t l nham kiem toan on djnh taluy cho moi giai phap tren tuyen dudng TTBG thude tinh S a n La.
K i t qua cCia nghidn ciru cua bdt bdo Id c a s d eho eac d a n vj t u van danh gia va lua chpn phuang an t h i l t k l mat d i e taluy nen dudng t u i n tra bien gidi thupc tinh S a n La noi rieng, eung n h u tren tuyen d u d n g TTBG khu v y c Tay Bdc ndi ehung d u p c phii hpp han, nham dam bao yeu eau kinh t l - ky thudt eua t u y i n d u d n g cd y nghTa rat quan trpng ndy.
Can m d rpng nghien ciru xet s y I n djnh nen dudng TTBG v d i mpi dieu kien dja hinh, dja c h i t , thuy van, cdc phuang an thiet k l khac tren todn t u y i n dudng TTBG khu v y c Tay Bac. Sir dung GeoSiope trong trudng hpp dp dyng cac giai phap bao vd mat d i e nhu trong co, neo, phun vOa gia co... khi dp doe mat ta luy Idn h a n , giam bdt khoi lupng thi cong cho t u y i n d u d n g TTBG, Idm c a s d khoa hpc va t h y c tien d l d a n vj t h i l t k l d l x u l t cdc giai phap on djnh nen d u d n g hp'p ly n h i t •
TAI LIEU THAM KHAO
[1]. M l Chat, Doan Minh Tdm, S6 tay phdng hd vd gia c6 nen dwdng, NXB GTVT, 1985; ..
[2]. N g u y l n Quang Chidu, Thiit ke tw&ng chiin dat, NXB GTVT, 2004;
[3]. N g u y l n Xudn True, D u o n g Hpc Hdi, Vu Dinh Phung, So tay thiet ke dwang d to, NXB Xay dyng, 2003;
[4]. Phan Xuan Dgi, Nguyen Chfnh Bai, Cdc giii phdp phdng chdng syt I& dit da trdn cfudng, NXB GTVT, 2 0 0 1 ;
[5]. Nguydn Khdnh T u d n g , RQ da trong cac cdng trinh thOy lai giao thdng, NXBXD, 2 0 0 1 ; [6]. D u a n g Hpe Hal, Ho Chat, Phdng ching cdc hien twang pha hoai nin dw&ng viing nOi, NXB khoa hoc vd ky thudt, 2002;
[7]. Dfi Van D g , Hw&ng din s(> dung phin mem tinh todn in djnh mdi doc Slope/W, NXB Xdy d y n g , 2001;
[8]. Bfi Giao thfing vdn tai, Tieu chuan thiit ki dw&ng d td; TCVN 4054-05, 2005;
[9]. Bfi tong tham m u u , Tidu chuin thiet ke dwang TTBG, Bp tong tham m u u , 2010.