KHOA HOC
J K E T Q U A N G H I E N ClTU KET CAU KHUNG THEP BO DA D^NG BA.C NU^6C GIA CO MAI DAP DA D 6 DAP D d KHI XA LU THI CONG
PGS.TS. T r 4 n Quoc Thirdng Phong thi nghiim trgng diim quoc gia vi Dpng luc hgc song bien.
Tom tit: Xd lu thi cdng qua dogn dap dd dd ddp d&, van tdc ddng chdy gdy xdi la mdi hg luu dap vd long sdng sau dgp, do do nghien cuu kit cdu gia co bdo vi an toan ddp dd do ddp dd khi xd lii thi cdng rdt quan Irgng. Bdi viit neu kit qud nghien cuu dgng kit cdu khung tkep bd dd gia cd mdi hg luu dap dd dd ddp da.
Tu khda: Dd do, khung thep bd dd, thep neo.
Summary: In flood discharge period while flow pass-through section of in-constructing rock fill weir, the flow velocity may cause downstream slope slide and river bed scouring. Thus research of structure of slope protection for safety of rock-filing weir under high flood flow discharge will play important role. The paper intends to present results of research of structure of steel gabion witk rock filling for protection of downstream slope of the in-constructive rock fill weir.
Keywords: Rock fill, steel gabion with rock filling, steel anchor bar I. M O DAU
Lya chgn phuong dn dan ddng, xa lii thi cfing la mgt van dfi quan trpng trong xdy dyng cfing trinh thuy lgi, thiiy di?n. Phuong an hgp li khdng chi tifit kifm kinh phi dan dong ma cdn nit ngdn thdi gian thi cdng. Dudi difiu kifin cd bdo V?, dap dd d6 bdn m^t cd thfi cho nudc trdn qua, tir do gidm quy mo cdng trinh ddn ddng. Ddy la mpt trong nhiing bien phdp dfi gidm kinh phi xdy dung, ciing la yfiu cdu cdn thifit trong thi cong. Ddi vdi thi cdng dap dd dd ban mdt ddc bi?t Id khi quy md cdng trinh ldn hogc luu lugng dan ddng ldn, nfiu khfing tan dyng ddi da uu difim ndy thi phdi tang thfim quy md cfing trinh dSn ddng khifin kinh phi thi cdng tdng them rat ldn, ddng thdi cudng dfi thi cdng ciing khd thda mdn nen khd dap img yeu cau an toan cho cfing trinh.
Khi ddp da do ddp dd cho nudc tran qua phai
tifin hanh bdo v | than dap ddc bifit la mai dap hg Iuu dfi tranh bj xdi Id phd hogi. Cd nhifiu bifin phap bao vp mdi hg luu: Da hoc, tham rg da, khung thep bd da dgng bdc nudc, tdm be tdng...Duoi ddy nfiu kfit qud nghifin cuu khung thep bd dd dgng bdc nudc (hinh 1,2 va 3)
Ngudi phan bi?n: PGS.TS Nguyen Ngoc Thdng Ngay nhgn bai: 24/7/2015
Ngay thong qua phan bi?n:10/8/2015 Ngay duy?t ddng: 28/9/2015
Hinh 1: Cdt dgc bd tri kkung tkep dgng bgc Ghi cku:
1. Than dap
2. Ldp da Idt khan bao v? mat dap day 2m.
3.Ldp da lat khan (ldp dfim) day Im.
4. Khung thep dang bdc nudc 5. Thep neo
6. Chan dap
64 TAP CHl KHOA HQC VA C O N G N G H E T H O Y LOl Sl3 28 - 2015
KHOA HOC ^I^^SSSSS^M
Hinh 2. Kit cdu I khung thep Ghi chii:
1. Ludi thep ^6,6 ludi 20x20 cm.
2. Ludi Ihep (j)6, d ludi 10x10 cm.
3. Khung thep <t)18.
4. Thep tdng cudng <j)18 - Kich thudc ghi la m
(3)
-(2)-d)
,l! /\ '~'- Z' \ i I ' / \ / \ 1 " / \
• " i • / \: / V : ^ ^-~
.„
Hinh 4: Qud trinh IH thi cdng II. KET QUA NGHIEN c i r u
Can cii vao duong qua trinh xa lu thi cong a tren, chti y toi 2 cdp lim luong (xa qua d^p da d6 dip do) la cSp chan lii co thcri gian xa lu dai nhit (Q=2000 m'/s) va cip lim luong lii lon nhit (dinh lii Q=4500 m'/s), vto t6c lon nhit a vimg chan d$p (muc nu6c ha luu dao dong) 2.1. Xac dinh cac thong so thuy lyc D I kilm tra su lam viec cua ro dd tren mai, tinh toan kiSm tra vcri 2 cip ltm luong Q = 2000m'/s va 4500m^/s. iTng voi moi cip luu lugng do dugc dudng m^t nudc, van toe... tai cdc mat cit diin hinh: dau, gi&a, cu6i va chan dap; chii y vung chSn d^p (myc nudc ha lim dao dgng. So d6 tinh toan va gia tri dau vao dimg trong tinh toan dugc the hi$n a hinh 5.
Hinh 3: So hpa thep neo Ghi chd:
l.Khungthepboda.
2. Th6p neo (j) 18 dai 12.50 m (ca u6n), dat each nhau t6i da 2.50m.
3. Cyc be tong chon ttong thSn dap, kich thudc 50x50x50cm.
Nhi$m vu nghien ctiu la xem xet ket ciu ban diu (neu 6 hinh 1,2,3) co ddm bao an toan khi xa lu voi cac cip luu lugng khac nhau (hinh 4), d^c bi^t xac dinh duong kmh thep neo, sy 6n dinh mai h? luu dap khi xa lu thi cong qua.
Hinh 5. Sa do tinh todn Qua thi nghi?m xdc dinh dugc cdc th5ng s6 thiiy lyc chinh (van toe, mach dgng van toe, do sau dong chdy vd dp suit mach dgng) cho 2 cap luu lugng tren, 6 vung chan dap, nhu sau:
2.1.1. tfng v(H cap q=9,50 m^/s.m (Q = 2000 m'ls)
Van toe dong chay V=6,00 m/s; m^ch dgng
TAP CH( KHOA HQC VA CONG NGHE T H O Y LOI Sfl 28 - 2015 6 5
I KHOA HOC j j ^ B n g i B i i M
van tfic V'=0,15 m/s
Dg sdu ddng chay : H=2,40 m; dp sudt mach dgng P'=0,30 mHiO (met cpt nudc) 2.1.2. iTng vdi cap q=21^0 m^/s.m (Q=4500 m^/s)
Van tdc ddng chay V=10,00 m/s ; mgch dgng van toe V'=0,30 m/s
Dp sau ddng chay: H=2,7 m ; ap sudt mgch dpng P'=0,40 mHaO (met cgt nudc) 2.2. Ly thuyet tinh toan
Ap dyng phdn mfim ANSYS tinh todn ket cau.
Philn m^m ANSYS cd khd ndng phan tich nhi^t dn djnh vd nhi?t khdng dn dinh trong he kit cau. Do trudng nhifit va trudng tham cd tinh chdt tuong ddng \i vgy cd thfi sir dyng cdng ndng phdn tich nhifit ANSYS dfi tinh todn kiem tra tham qua khdi da do ddp dd.
De md hinh trudng nhifit do vd md hinh truong tham tuong dfing, can thda mdn cdc difiu kifin dudi ddy:
2.2.I.Tuomg tif hinh hgc.
Bifin ngodi cua md hinh trudng nhift dp vd bifin ngodi ciia phgm vi nghifin ciiu tham tuong ddng hmh hgc. Khi pham vi thdm la ldp dd d6ng dfiu, mfi hinh cimg cdn ddng dfiu; khi phgm vi tham Id ldp dd khdng ddng deu, yfiu cau trong md hinh nen cd dudng phan chia dan nhi?t khdng gidng nhau bdo dam tuang ddng dudng phan chia ldp dd khdng gidng nhau.
2.2.2.Diiu kiin biin tucmg dmntg.
Tiic la bifin dogn nhift ciia md hinh md phdng nhi?t dp vd bifin ngdn nudc phgm vi thdm la tuong ducmg. Bifin dan nhifit va bifin thdm nudc la tuong duong, nhiet dp trfin bien din nhifit vd cgt nudc tren bien t h ^ nudc la tuong duong.
2.2.3. Md hinh tinh todn
Tinh todn kifim tra kfit cdu khung thep bd da bdng phan mfim ANSYS. Md hinh phdn td hfiu hgn md phdng kfit cdu khdi da dd bdo ve mdi hg Iuu bdng khung thep bd da d hmh 6
Hinh 6: Md hinh phdn tu hOu hgn Khoi dd dd va da trong rp sir dung phdn tii PLANE55 (phdn tir tinh toan nhifit) va PLANE42 (phdn tir tinh toan kfit cau)- hmh 7
Hinh 7: Phdn tuPLANE42 Khung rp thep sir dyng phdn tu LINKl. Day la phdn tii thanh 2 chifiu chiu keo nen dpc tryc.
Thanh thep neo sir dung phdn tu BEAM3- hmh 8. Day Id phdn tu thanh 2 chifiu chiu keo nen dgc tryc va chiu udn. Dgc tnmg hinh hpc ciia phdn tir la kich thudc mgt cat ngang cua phdn tir.
U.
Hinh 8: Phdn tu BEAM3 Bau tien tiSn hdnh phan tich trutmg thim sau do tien hanh phan tich chiu Iyc ciia ket can.
Bien day dap vd bien thugng lim ddp la bien khong tham. Bien mat dap la bien tham nuoc
66 TAP CHI KHOA HOC VA CONG NGHE T H O V t p i SO 28 - 2015
ung vori cdt nudc tinh todn ddng mgt trfin dinh va mai ha luu la bifin thoat nudc.
Gan cdt nudc tdng d bien mat dap vd bifin ha luu dgp, se phdt sinh ddng thdm trong khdi da do vfi ha Iuu va phd cdt nudc ap lyc trong thdn dgp (xem hmh 9).
Hinh 9: Ddng thdm qua ddp dd do ddp dd 2.3. Kk qua tinh toan k^t c^u 2.3.1 Tinh todn lire keo
tTng vdi mdi cdp luu lugng khac nhau xdc dinh dugc phd chuyfin vi cua ket cdu, ap luc
tac dyng len rg da mdi hg luu do ddng thdm 2.3.1.1.fj'ng v&i cdp luu lu0tg q=9,50 m^/s.m gay ra va lyc keo trong thanh neo. Dudi ddy (Q = 2000m^/s)
neu kSt qua ung voi hai cip luu lugng Q=2000 ^^c doc lon nhit trong thanh neo Nk = 1,719T m'/s(hmhlO)vaQ=4500m'/s(hmhll) ^
Kiem tra kha ndng chiu keo ctia thanh neo iing voi duong kinh thanh neo (t)25:
Hinh 10a: Luc keo trong thanh neo
1,719x10'
, =87,5(daN/cm')<—R^= — x2100 = 175o(daN/cm')
" 3,1416x2,5' ^ ' k ' 1,2 ^ ' Ok=87,5(daN/cm^) < [RJ =1750 (daN/cm^)
Thanh neo (t)25 dii kha ndng chiu keo.
+ KiSm tra khd ndng chiu keo ciia thanh neo iing voi duong kinh thanh neo i}> 18:
' • ' ^ ' ^ ' ' " ' ' =169(daN/cm')<SR =-i-x2100 = 175o(daN/cm') 3,1416x1,8^ ^ ' k 1,2 ^ ' Ok=169(daN/cm^) < [Rk] =1750 (daN/cm^)
Trong do: -2100 (daN/cm^) la ling sudt keo cho phep cua thep neo - 1,2 la he s5 hieu chinh
Thanh neo (|i!8 dii khd ndng chiu keo.
TAP CHl KHOA HOC VA CONG NGHt T H O Y LOI SO 28 - 2015 6 7
I KHQAHOC ^KSSBSS^M
Do cdc rp thep dugc ddt chdng Ifin nhau cd ma sdt do trpng lugng bdn than ldn, cac thanh neo chi lam nhifim vy tdng kha ndng dn dinh tdng thfi cua mdi nen lyc keo ldn nhdt trong thanh neo tucmg ddi nhd, cac thanh neo dam bao khd nang chiu lyc khdng bj keo diit. Tuy lyc keo nhd nhung theo kinh nghifim d the gidi vd trong nudc dfiu bd tri thanh neo; vi khi xd lii dot nggt ddng chdy tdc dgng theo 2 phuong Id ddng tham trong than dap ra va ddng chay mat d trfin dinh dgi xudng mai dap, ... dfi gdy mat dn dinh kfit cau gia cfi bao vfi mdi dap. Do do cac cdng trinh thi nghifim mfi hinh vd thyc te thi cfing deu bd tri thep neo nhu Tuyen Quang vd Cua Dat, ... Theo kinh nghifim thudng bfi tri thanh neo <|>>25mm, chiing tfii tinh toan chi dimg (|) 1 Smm la ddm bdo an todn.
Tir ket qud tinh todn ddi vdi 2 dudng kinh thanh neo (t)18 vd <(i25 d tren cho thdy: thanh neo dli khd ndng chiu lyc, my nhifin de dam bao difiu kipn ve kinh tfi vd ky thudt kifin nghi chpn dudng kinh thanh neo ^\S\a ddm bdo an toan. Trfin md hinh dd thi nghipm cd thanh neo (1)18 kfit cau on djnh.
2.3.1.2. ung vdi cdp luu luang q = 21,50 m^/s.m (Q=4500m^/s)
Hinh 11: Phd chuyen vi tdng tgi mdi hg luu JR—
Hinh Ua: Luc keo trong thanh neo Lyc dgc ldn nhdt trong thanh neo Nk = 2,193T + Kifim tra kha ndng chju keo cua thanh neo iing vdi duonng kinh thanh neo (j)25:
g , - , ^ ; ! ^ ^ ' ' ! , " ' = = l l l , 7 ( d a N / c m M < - R , ^ J - x 2 1 0 0 = 1750(daN/crnM 3,1416x2,5' ^ ' k 1,2 ^ '' CTk=l 1 l,7(daN/cm^) < [R^] =1750 (daN/cm^)
Thanh neo iti25 dii khd ndng chiu keo.
+ Kiem tra khd ndng chju keo ciia thanh neo iing vdi dudng kinh thanh neo (j) 18:
< ' k = j j ^ j ^ ^ Y ^ = 2 1 5 ( d a N / c m ' ) < ^ R , = - L x 2 1 0 0 = 1750(daN/cm') CTt=215(daN/cm^) < [Rt] =1750 (daN/cm^)
Trong dd: - 21 DO (daN/cm^) la img sudt keo cho phep cua thep neo -1,2 Id he sd hifiu chinh
Thanh neo if\ 8 dii khd ndng chiu keo.
68 TAP CHl KHOA HQC VA C O N G N G H E T H U V LOl S(5 28 - 2015
KHOA HOC Do cac rg thep dugc d^t ch6ng 16n nhau co ma
sat do trgng lugng bdn thdn lon, cac thanh neo chi ldm nhiem vu tang khd nang on dinh tong the cua mdi nen lyc keo Idtn nhit trong thanh neo tuong doi nho, cdc thanh neo ddm bdo khd nang chiu luc khong bi keo diit. Tuong tu nhu cip luu lugng Q =2000m'/s, d6i vol cip luu lugng Q =4500m'/s, dS dam bdo diSu ki6n v6 kinh ti vd ky thuat kiin nghi lya chgn duong kinh thanh neo (|il8 la ddm bdo an toan. Tren mo hinh da thi nghidm co thanh neo (jilS kit cdu on dinh.
2.3.2.Ki8m tra lyc cit vdi thanh neo ({ilS
Iriiirr
= — — • J
^_i:i
p m . K U f f i t nti ifw 49N ">»
^S&3^
i^ SIF 4t ^ '»°9
AN
Hinh 12: Luc cdt trong thanh neo img vai cdp luu lu^g Q = 4500m^/s Lyc cdt trong thanh neo rdt nhd xdp xi bang 0 (xem hmh 12). Hay ndi each khac thanh neo rg thfip chu yfiu chju keo.
Thanh neo 18 du khd nang chiu lyc keo vd lyc cat.
2.3.3.Ki^m tra on dinh:
Vdi cdp luu lugng q=9,50 mVs.m (2000 mVs) va q=2I,50 mVs.m (4500 mVs)
2.3.3.1. So lieu tinh todn
Tinh todn trong trudng hgp chifiu cao khdi da khi trdn nudc la 16.0m. Mat thugng luu khdi da do dugc bao ve bdng Idp bfi tfing khdng thdm vdi he sfi mdi 1:1,4. Mat ha luu khdi dd do dugc bdo ve bdng khung thep bd da dang bdc nudc dgt trfin mai vdi he sd mdi 1:1,5.
Chifiu dai mat dap tgi cao trinh tran nudc L - 239m. Chi tifiu ca ly cua cac logi vdt lieu diing trong tinh todn nhu sau;
Bang 1: Chi tieu eg ly cua vdt lieu diing trong tinh todn
TT 1 2 3 4
Vdt lieu Be tong cot thep Khoi da dd Rgda Thep neo
bh
(T/m') 2,50 2,10 2,00 7,85
E (kN/m^) 2,4 10' 2,6 10' 2,1 ID' 2,1 10'
0,20 0,25 0,25 0,30 He sd bdo ddm [Kod]- dugc xet theo quy md, nhifim vy cua cdng trinh, ddi vdi cdng trinh cd mai ddc nhdn tgo bdng da ddp cd thfi ldy theo bang sau:
He so on dinh [Kod]
Dac biet 1,25
Cap I 1,20
Cap II, III, IV 1,15 2.3.3.2.Ket qua tinh on dinh
Kifim tra fin dinh mai hg luu dap da dd ddp dd bdng phdn mfim Geo-SIope
Kfit qud tinh toan neu dhinh 13-15
Hinh 13: Md hinh tinh todn
TAP C H l KHOA HOC VA C O N G N G H f THUY LOI S(5 28 - 2015 6 9
I KHOA HOC MSSBSSiI^B
Q S2
J 6 16 26 36 46 56 se 76 86 96 106 116 126 136 146 156 166 176 186 136 206 216 226 236 2*6 2S6 366 276 386 296 3M
Khoang Cach
Hinh 14: He so on dinh mdi doc tinh todn ling vdi cdp luu luong Q = 2000m /s (K=l,494)
)i*r36i •
4 6 16 26 36 46 56 66 76 M 96 106 116 126 136 146 156 IGG 176 186 196 206 216 226 236 246 2S6 266 276 286 296 3ffi
Khoang Cat^
Hinh 15: H? sd dn dinh mdi ddc tinh todn img vdi cdp luu luang Q - 4500m /s (K= 1,361) Ket qud tinh cho thay:
Vdi cip luu lugng q=9,50 m'/s.m (Q=2000 m'/s)
K=1,494>[K]=1,20
Vdi cip luu lugng q=21,50 mVs.m (Q=4500 mVs)
K=l,361 > [K]=l,20
Nhu vay mdi on dinh idiong bj trugt.
III. KET LUAN
Qua thi nghiem mo hinh vd tinh todn kilm tra ket cdu, on dinh gia co mai ha luu dap da d6 bing khung thep bo dd co thi nit ra mot so nhan xet sau:
Khung thep bo da co ciu tjo ddc biet (khong phdi rp da chdng bao lut): Khung dugc gia cong che tao bdng thep c6 dudng kinh d>18mm, gia cudng them thep cd duong kinh dil Smm, mat ludi xung quanh bang thep i|»6 hdn thanh 6 vuong cd kich thudc 20x20cm (rieng mjt truoc 6 vudng cd kich thudc lOxlOcm). Dd bo trong rg cd
duong kinh d>25cm. Cdc khung thep bd da dugc neo vao than dap bing cae thep neo (}il8 ddi 12,50m(ca uon), cac thanh neo dat each nhau tdi da 2,50 m. Kit ciu nhu tren ddm bdo on dinh, an toan cho cdng trinh khi xd lu thi cong qua doan dap da dd dip dd.
Cdc ket cau tren phii hgp vdi cac cong trinh: Chiiu cao dap da dd dip dd HSI 6m, luu lugng don vi lii thi cong q<21,50 m'/s.m.
Tuy nhien di ciing c6 them co so khoa hoc cho viec ung dung giai phdp tren vdo thyc te, can tiep tuc thyc hien cdc ngi dung nghien cuu sau;
Nghien ciiu chi do thuy lyc dong chdy qua cdng trinh dan ddng; nghien ciiu xdi Id ha luu trSn mo hinh long mim; nghien ciiu kit cdu gia c6 bao ve 2 vai dap, 2 vai bac nudc va 2 mdi bd sdng ha ltm dap; nghien cuu kit cau gia cd mdi ha luu dap bdng tim be tdng cdt thep
Nhiing npi dung nghien ciiu tren chiing tdi se trinh bdy vao dip khdc.
70 TAP CHl KHOA HOC VA CdNG NGHf THOY LOI Sfi 2S • 2015
I KHUA HOC ^ . J . I J I t l J M ' l ^ TAI LIEU THAM KHAO
[I] QCVN 04-05-2012, Cdng trinh thuy lgi- Cdc quy dinh chu yiu vi thiit ki.
[2] TCVN 9147-2012, Cong trinh thuy lgi - Quy hinh tinh todn thuy lyc dap trdn [3] TCVN 9151-2012, Cong trinh thuy lgi - Quy trinh tinh todn thuy luc cdng dudi sau.
[4] TCVN 9610-2012, Cong trinh thuy lgi - Yeu cau thiet ke din ddng trong xdy dung.
[5] X.V.ZBAS, thuy lyc chan long sdng , Vd Phan, Truang Nhat Thanh dich, NXB KHKT, nam 1974.
[6] Sd tay tinh todn thuy lyc, Luu Cdng Ddo, Nguyen Tai djch tir tiing Nga, NXB ndng nghiep nam 1974
[7] Sd tay thuy cdng, Matxcova nam 1988.
[8] Dan ddng thi cong cdng trinh thdy lgi, thiiy dien, Trudng dai hpc thuy lgi nam 2009.
[9] Thap lii qua dap da do dang xdy dyng dd, Studenichnikov B.I, tap chi KHKT trudng dai hpc xay dyng Matxcova, ndm 1961.
[10] Su tien trien ve dan ddng thi cong va vugt Id cua dap da do be tdng ban mdt d Trung Qudc, Trieu Tang Khdi, Tdng cdng ty thiet ke quy hoach thuy lgi, thuy dien, nam 2005.
[II] Phan Dinh Dai (1992): Thi cdng dap thuy di$n Hda Binh- NXB xay dung, HdNdi [12] Nghien ciiu thi nghiem trdn qua mdt dap ban mdt, Hd Khii Lipt- Du Ba, Phdng nghien cuii
Thuy cdng Vien nghidn cuu khoa hpc thiiy lgi Nam Kinh, nam 1997
[13] Vien Nang Lugng (2002), Bdo cdo kit qud thi nghiem md hinh cdng trinh thiiy dien Tuyen Quang.
[14] Vi$n Khoa hgc Thuy lgi (2006), Bdo cdo ket qua nghien curu thi nghiem md hinh thuy lyc xa lu thi cdng qua ddp da dd dip dd, cdng trinh Cua Dat, Thanh Hda.
[15] Trin Qudc Thudng, (2005): Thi nghiem md hinh thuy luc - NXB xdy dyng, Hd Npi.
[16] Trin Qudc Thudng (2008): Bao cdo tong ket de tdi cdp nhd nudc ma sd 6-201J [17] Bao cdo thi nghiem mo hinh thuy luc dan ddng thi cdng cdc cdng trinh: Sdng Bung 4, Sdng
Tranh 2, Ha Se San 2, Ban Chat,... Vipn Khoa hpc Thuy lgi Viet Nam
[18] Bao cdo thi nghiem md hinh thuy lyc cdc cdng trinh: Ddng Nai 3 va 4, Daktit, Serepok 3, Sesan 3...Vien Khoa hpc thuy lgi Midn Nam.
TAP CHl KHOA HOC VA CONG NGHE T H O Y LOI 5(5 28 - 2015 71
