I KHOA HOC B I E S 3 ! B I I ^ B
y C 6 N G T A C Q U A N L Y C H A T LU'ONG T R O N G QUA TRINH THI C O N G KE DE BIEN
TS. Dong Kim Hanh Truang Dgi hgc Thuy lgi
Tdm tat: Ddm bdo chdt^ lugng Irong qud trinh thi cdng Id mpt yeu cdu quan trgng vdi cdc cdng trinh ke di biin. Bdi viit da khdi qudt bien phdp ihi cong ke di biin lir lap bdo vi mdi de (thdn ke), tdng lgc vdphdn gia cd chdn ke. Viec thi cdng tirng bp phdn diu cd cdc yeu cdu ky thudt rieng Vi vgy de cdng tde thi cdng ke di biin dgt chdt lugng thi phdi ddm bdo cdng tac qudn ly chat luang trong tirng giai dogn thi cdng cdc bd phdn. Tuy nhien, trong qud trinh thi cdng mdt sd vdn di loi ky thugt vdn xdy ra ddn den hu hdng cho cdng trinh vdi nguyin nhdn chu yiu do qud trinh thi cdng ciia nhd thdu xdy dirng. Tir phdn tich nhiing nguyen nhdn dd, tde gid dd dua ra mdt sd gidi phdp nhdm ndng cao chdl lugng trong qud trinh thi cdng ke de biin.
Tir khda: Chat luang, ke de bien, nhd thdu, thi cdng
Summary: Ensuring quality in the construction is an important requirement for the sea dikes.
This paper outlined construction method from the sea dike slope protection layer (body embankments), filtered and toe. The construction of each department has its own technical requirements. So for the construction of sea dike embankment quality must ensure quality management in each stage of construction parts. However, during the construction, some of technical problems still apear errors lead to damage to the building with the main reason due to the construction of the building contractor. From the analysis of the causes, the author has made measures to improve the quality of the sea dike construction.
Keywords: Quality, sea dike, contractors, construction
I. D ^ T VAN Bt. km ke bidn. Vai ba th^p ky gan day, ben canh Vi?t Nam CO tren 3260 km chiSu dm b a biSn, " f ' ^ g " « l u c cua nha nuoc va nhan dan ta, mpt trong d6 CO hon 2000 km 14 de biin. Lich sil ^° ^V to cung co, nang cap he thong de bien da i- u.ux uA-w' • , • u; vhi .L. n, thuc U?n, nhu: PAM 4617 (1993-1998); PAM hmh thinh de bien nuoc ta co tu kha som, tu • , „ ' , , „ „ „ , . „ . „ , , . i thS ky 13 Ban d i u la nhitag doan de nho le, " 2 5 (1996-2000) cua FAO; hoSc nr cac nguon ,?« < o T n - f x ' x % • A i a , i „ ; tai trg nhu ADB (2000), CARE, CEC, OXFAM thap yeu a BSc Bo, dan dan dugc noi ket lai, ,, , . t i- , - s . . < , bfii tnic them, de den nay tro thanh mpt "trucmg ...lam cho cac tuyen de bien dugc ciing co va thtah trade biin" dai t5ng cpng 1670km. Phia " ^ ^ ^^P i t o g ke.
Nam de biin hinh thanh mupn hon, hi?n ting Theo thing kS, trong 50 nSm qua, nhiet dp chieu dJi de biin tii Quang Ngai d i n K e n hung binh tai Viet Nam da tang 0,7 dp C, muc Giang khoang 896,84 km, trong do co 568,38 nuoc biin dang 20 cm. Viet Nam da va dang km dS biin; 283,09 km de ctia song va 45,37 chiu anh huong cua biin d i i khi hau (BDKH).
Thien tai, bao lut, ban ban da dien ra khic liet hon truoc. Vi?t Nam dugc cho la mpt trong NguM phan bi?n:GS.TSVu Thanh Te ^ ^ „u5c chiu tac dpng nhit cua BDKH;
Nsiv nhan bir. 01/4/2015 ^, , ; . i , , . ; . . . Syftongquaphanbi^n:20/4/2015 ^ " " 8 * ° <=° " h ' « " ™ " 8 ™ " ' " ^ " ^^ ' " "89P- Ngiy duy^t dSng: 24/4/2015 Biin doi khi hau gay ra thien tai thuang xuyen
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I KHOAHOC ^ . i . l 5 ! J 5 i a ! l ^ hon, nhung con bao c6 cudfng do manh se cang trd nen phd bidn va gia tang sue tan pha [1].
Bao manh thudfng kem theo nuoc dang theo bao. Nuoc dang khi co bao cdng voi trieu cudmg tao ra nhflng dgt sdng danh true tiep vao dd bien, tran qua dd gay xdi 16 va v5 de, gay ngap lut tren dien rdng cho vung ven bien va anh huong nhidu den he thong ha tang co sd cung nhu ddi sdng ngudi dan ven bidn.
Nhimg nam gin day, xuat hien nhimg con bao c6 cudng do sidu manh tren bien, gia tang sire tan pha vd kinh td, xa hdi va mdi trudng ven bien. Thdng ke cho thay, vao nam 2005 xuat hien con bao sd 2 va sd 7 (dae biet la con bao sd 7) rat manh tren cap 12 vugt qua tan suat thiet ke cac tuydn dd bidn da do bg vao nuac ta trung voi trieu euong gay ra nudc dang cao 3,5 - 4 m, ddng thdi sdng manh tren 6 m tai cac vung ven bien Bac bg tu Hai Phong ddn Ha TTnh da Iam nuoc tran qua de va vo de nhieu noi, gay thidt hai Idn. Vdi cac doan de bidn Tay, sau cac con bao, toan tuyen de bien Tay dang xudng cap nghiem trgng can phai dugc xu ly gia cd ngay dd bao vd than de khdng hi vd khi ma trieu cudng, song bien Idn thudng xuyen hoat ddng manh.
Ddi di?n vdi BDKH ngay cang gia tSng la nhung con sidu bao cd cuong do rit manh, thay ddi khd luong nhu hien nay thi cdng tac quan Iy chat Iugng cdng trinh khi thi cdng cin phai nang cao hon niia. Vide dau tu nghidn cuu cac bidn phap nham nang cao chit Iugng thi cdng ke bao vd mai cac tuydn de bidn la rit cap thiet.
II. CONG TAC THI CONG KE DE BIEN Vd CO ban, ke dd bien bao gdm cac bd phan:
Idp bao vd mai de (than ke), ting Igc va phin gia cd chan ke. Vide thi cdng timg bd ph|in deu cd cac yeu cau ky thuat rieng. Vi v^y dd cdng tac thi cdng ke dd bidn dat chat Iugng thi phai dam bao cdng tac quan ly chat Iugng trong timg giai doan thi cdng cac bd phan, hang muc cua cdng trinh.
Hinh 2.1: Mat cdt thi cdng ke de bien 2.1. Thi cdng larp lgc
a) Ldp lgc bdng vdi dia ky thugt
Ldp Igc don gian va thuong dung hidn nay la Idp lgc dimg vai dia ky thuat cd phu da len trdn. Ldp vai dia ky thuat dugc trai tir tren bo xudng day sdng, day bien. Trong gioi han cho phep nhan cdng tren can co the trai vai dia ky thuat song Cling CO trudng hgp phai dung tdi thg lan. E)di vdi cac cdng trinh Ion, ngudi ta phai dimg tau keo cuon vai dia k^ thuat Idi thep tit trdn bo xudng (Hinh 2.2).
Hinh 2.2. Trdi vdi dia ky thudt trong gia cd mdi dcm gidn Sau khi thi cdng xong lop lgc, tau md thanh sd dd da phii ldn ldp vai dia ky thuat, bit diu tu phia chan ldp gia cd Idn tren d% cd dinh ldp vai dia kJ thuat, khdng cho nd trugt xudng. Thi cdng vai da ky thuat thi mat ndn phai dugc dim chat, bing phing; cac vat sic nhgn tren mat ndn phai dugc loai bd truoc khi trai vai dia, voi nhung viing co van tde ddng chay m ^ phin gdi diu giiia 2 tham vai ndn dat xudi theo dong ehay. Doi vdi viing duoi myc nuoc bidn thi kich thuoe chdng mep vai tdi thieu phai duoc 2 Om b) Ldp lgc bdng cdt lieu rdi
Cac lop lgc nay khong cin dim, nhung phai dugc thi cdng dam bao cac lop ddu nhau theo chidu day qui djnh theo thidt kd (cho phdp chdnh
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Idch 10%) [2]. Cii m5i 20m dai ke, cac m l u soi cat diing lam lop lgc phai dugc liy de phan tich cap phdi h ^ .
c) Cdc sai sdt thudng gap khi thi cdng - Nha thau chua quan tam dung muc ddn cdng tac thi nghiem kidm dinh chit lugng vai lgc trudrc khi sir dung.
- Cac doan vai lgc khi trai khdng dugc gdi Idn nhau nhu tidu chuSn quy dinh gay ra khe hd giiia cac doan vai. Mdt sd truong hgp khdng dugc ghim ch^t vao dit ndn gay xd lech, phdng com trong qua trinh thi cdng.
- Chidu day, cap phdi lop lgc bang cdt Udu khdng dam bao dung ydu cau.
2.2. Thi cdng chan ke (chan khay) Dd b^o v? su dn djnh ciia khdi gia cd mai, can bd tri be doi tai vi tri n6i tidp giira chan ke va b&
bidn, ggi la chan khay (Hmh 2.2).
2.2.1 Ky thugt thi cdng
Thdi didm thi cdng chan khay la khi mue nuoc thuy ttidu xudng thap ddn cao trinh mat bai tu nhidn tuydn ke. Ndn phan tuydn cin thi cdng thanh nhidu doan, thi cdng cudn chieu, doan nao dlit didm didm doan diy. Da hoc dimg de thi cdng chan khay phai cd du trgng l u g i ^ dd chiu dugc tac dung cua dong chay do song tao ra 6 chan de.
2.2.2 Cdc sai sdt thudng ggp khi thi cong
Hinh 2.3. Cdc dgng chdn khay ke
• Khdng sir dyng diy du cac Ioai may thi cdng chuyen dung, ihuor^ su diing mdt Ioai may (nhu may xuc) dd lam ddng thdi nhidu cdng tac (dao mdng, ciu dng buy, tha da hoc...).
- Tun tuyen, cao trinh hang chan khay thudng bi lech so voi thidt kd.
2 3 . Thi cong than ke 2.3.1 Ddldtmdi
Chidu day ke da cdn phy thugc vao kich ihuoc cua cac vidn da, thudng phai dam bao la bgi sd cua kich thuoe vidn da. Khi lat da cac vidn da Ion diKfc xdp dat ddng ddu tren toan bg didn tich mai ke. Cac vien da nhd hon dugc dat xen kd cac vidn da Ion, lam cho cac vidn da dugc dat kbit nhau, an khop nhau. Bd m5t ke khdng dugc cd khe hd Idn, ke da cd do day ddng deu.
Da xay giai quydt dugc vi?c thay the cac ^ien da Ion nang ma vin dam bao yeu cau chit Iugng cdr^
trinh. B^ khudn (go hoac ttiep) len bd mat ke flieo tuin tu Iam tir tiiip den cao. iChdi da phai Aigc tuci nuoc truoc khi do vua VQa se dugc dd h ( ^ phut vao cac khe hd giua cac vidn da. Viec dat cac Idp lgc bSng cat sdi dugc tien hanh ddng thdi voi vi?c dat xdp (M ke. Bat diu lam ttr phin chan truoc rdi lam din ldn, dat lop ddm lgc xong trSn d^ ke [2].
Cach Iam nay can Ihidt dk tranh Iam hdng Idp Igc.
Khi ^ rai cat, soi Igc hoac vai lgc, soi tmoc khi ^ cac vidn da cin rai mdt lop giay diu hoac bao xi mSi^ rdi rai mdt lop viia day 0,1m dd tranh viia xi mang Iam giam tac dung lgc. Trong qua trinh dd phut vua. cin dimg xabeng nay rung cac vidn da Ion dd vua nhet hdt vao cac khe.
2.3.2 Be tdng Idt mdi
Chit lugng ciu kidn be tdng thdng thuong phu thugc ph&i ldn vao vide kidm soat tai thdi diem trgn bd tdng. Ham Iugng va trinh tu cua mdi Ihanh phSn dua vao me ttgn va thoi gian trdn dugc kiem tra dinh ky dd dam bao su thay ddi la tdi thidu. Vdi didu kien thuc td, mau dd Ihi nghiem cdt heu va miu thi nghiem be tdng phai liy trong ciing mdt me ttgn. Mdi loai be tdng cin liy n ^ u mdt lin cho mdi ngay ddi vdi be tdng dd tai cho. Mau cho cdt lieu bd tdng va be tdng phai dai difn cho vat heu dugc sii dung va be tdng dugc dd moi ngay.
Mat khac, ndu do im cua cdt lieu la ddng nhat va lugng nuoc trdn vao hon hgp dugc khdng chd,
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thi nghidm dg sgt se the hi$n su thay (^i thanh phin cip phdi h o ^ cac sai sdt khi trgn.Cac cau kidn dugc van chuydn ddn vi tri cdng tiinh bing d td co cau tu hanh, dung nhan cdng I ^ dat ciu kidn vao vi tri thidt ke. Tien hanh song song ca cdng tac rai ^ dam lot va lap dat cau kidiL Khi 1^ ghep chii y I ^ ghep mgt hang dgc tir dudi ldn tren den cao trinh muc dang cao nhit cija ng^y tiep theo, sau do diing I^i va chuydn sang I ^ ^ hang dgc ke ti^. Nhu vay khi muc nuoc dSng Idn cao vin co thd tien hanh thi cdng tidp phan mai ke ben tren muc nuoc. Nho do ma tidn dg thi cdng se khdng bj gidn d o ^ [2].
2.3.3 Cdc sai sdt thudng gap khi thi cdng Ddi vdi thi cdng da lat mai thi thucmg gap trud'ng hgp da hoc khdng dit trgng lugng, chidu day lop dd khdng dam bao. Da hgc khdng dugc chen kbit, nhieu vien da de dang hi nhic len, thidu lien ket vdi cac vidn xung quanh. Vila dung dd xay chit khdng du cudng do dan ddn bj bong ttdc khdng Udn ket dugc cac vidn da.
Doi v6i be tdng lat mai thi chit Iugng bd tdng, mac be tdng cau ki^n khdng dam bao. Cac ciu ki$n chua dii tudi 6& sii dung lip d$t. Sd lin liy mau thi nghi?m kidm dinh chit lugng be tdng chua duoc dam bao.
ra. Y^U T 6 A N H HirofNG BtS CHAT LlTi^fNG THI CONG
Chit Iugng cdng tiinh xay dimg noi chui^ muon dg.t dugc cin phai c6 su quan ly chat ehe va xuydn sudt cua tit ca cac chu the tham gja, tii su quan ly cua Nha nuoc ddn s\r quan \f cua Chii diu tu, cac nha thau, td chiic g i ^ s ^ thiet kd, tiu cdng... Trong do yeu to dugc danh gid Id quan trgng Snh hucmg true tidp den chat lugng cdng tiinh xay dyng do !a qua trinh thi cdng hay qua trinh trye tiep "san xuat" ra san phim Id cdng trinh xay dur^. Va trong qua trinh nay trdch nhi$m Idn nhat thugc ve cdc nhd thiu till cong xay dyng cong trinh.
Khi I|lp dy an diu tu, cdc don vj tu vin thidt kd ciing da tinh todn den cac tac dgng cua bao, sdng bien. Tir do dd ra cdc bi?n phdp, ydu ciu ky thu§t can thidt. Nhimg khi thi cdng cac nha thiu khdng ddp (ing dugc tdt, diy dii cdc ydu ciu kf thu^t, ydu cau chit lugng. Nhihig vin de ma nha thdu thi cdng ke dd bien hay gap phai nhu:
- Chit lugng bd tong, mde bd tdng khdi^ ddm bdo, khdng phu hgp vdi mdi trudng Idm vi?c cua cau kidn dan den sau mgt thoi gian Iam vide cdc ciu kidn be tong lat mdi ke bj xam thyc, mdi mdn de lg ra lop da.
Hinh 3.1. Xdm thuc, dn mdn be tdng ke bien Cdt Hdi, Hdi Phdng - Van dd Iiin sut mdng gia cd mgt phan nguyen
nhan la do su loi cudn vat lieu lgc boi song nit Sy Idi cudn vat lieu lgc ra ngoai chi xay ra dugc neu CO chuyen vj Ion cua mdng gia cd dudi tac dyng cua dp lyc diy ngugc tir ttong than de khi sdng nit. Ben canh do, nguydn nhan chu quan la
do chit Iugng tiu cdng kdm, khdng ddm bao sy dn dinh ciia dit d ^ ttdn mai ke, chan khay ke khdng dam bdo bj sdng pha vd nhi^u doan 1dm tiian va mai ke bj syt liin, hay tiiidu cac eong trinh phy ttg tiiodt nuoc mua va nuac thai tir khu dan cu ra bidn (Hinh 3.2; Hmh 3.3).
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Hinh 3.2. Mdi ke bi lun, sut Hinh 3.4 cho thay tmh trang cac mang gia cd bj bong trdc do sdng d dd bidn Nam Djnh.
Tinh trang ky thuat nay se dan ddn mit an toan cho de bien. Nguyen nhan cua vi?c bong trdc mang gia cd la do ttgng lugng vidn gia cd khdng du giir dn dinh, cac vidn gia cd khdng
Hinh 3.3. Mdi ke bi truxrt du lien kdt vdi nhau.
Hinh 3.5 thd hien mdt doan de bj pha huy mang gia cd phia bien dan ddn phd buy de, pha buy nen de. Ndn dd bj sdng xdi sau, nen phdi gia cd Iai ndn bj xoi.
Hinh 3.4. Cdu kien bi bong trdc Til thyc ttang chit kgng thi cdng va nhiing hien tugng hu hdng tten co the nhan thdy yeu td dam bdo chat hrgng trong cdng tac thi cdng cd anh hudng rdt 1cm ddn su on djnh, tudi thg ciia cdng trinh ke dd bidn.
3.1 Nhdm cac ydu to chu quan 3.1.1 Yeu td con ngudi
Don vj thi cdng la don vi Idm vi$c trye tidp tten cdng trucmg, ]a n^udi bidn san pham xay dyng tren bdn ve thiet ke thanh hien thyc. Vi vay yeu td dau tidn quydt djnh chat hrgng san phim xay dyng la nang lyc chuyen mdn cua mdi ca nhan trong don vj thi cdng. Ben canh dd, mdi ca nhan ciing nhu toan bg don vi ddu phai dugc bdi
Hinh 3.5. Mdi dephia bien biphd hity duong, dao tao nhan thiic ve chat hrgng va tam quan trgng ciia quan ly chit hrgng cdng trinh xay dyng de hg cd y thiic thyc hien nghiem chinh.
Ddng thdi huong mgi boat dgng ma hg thyc hidn ddu phai vi myc tieu chit Iugng.
Ngoai nang lyc thi y thiic ciia mdi con nguoi trong cdng tac xay dyng ciing rat quan trgng doi vdi chit hrgng cdng trinh. Ching ban nhu cac mau thi nghiem dua vdo cdng trinh, don vi thi cdng giao cho mpt bd phan chuyen traeh, nhung bo khdng tiii nghidm raa chung nhan ludn dan ddn khdng dam bao. Vi dy nhu nudrc diing trpn bd tdng n ^ khdng dam bao tidu chuin vdn dugc cho phep tiii cdng dan ddn chit Iugng bd tdng khdng ddm bao.
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I KHOAHOC ^ A i ; M ? r . f f i ^ 3.1. J Chdt lugng nguyen vdt lieu
Kgu> en vat heu la nhflng thanh i^idn co ban cau thanh len san prfiim cdng tiinh xay dyng, vi vay mudn c^ig trinh xay dung dat chit lugng thi nguyen v | t U^u j^iai ^ m bao du cac ydu cau, tieu chuan vd chit Iirgi^ Mudn quan Iy chit lugng cua ngi^foi vai Udu tmdc tien jdiai can cii vao cac tieu chuan, q i ^ pham cua Nha nuoc ve cac thanh j M n nguyen vat lieu su dmig. Vi du nhir Cat, soi, nudc, ximang... dung chd tao be tdng lat mai I^iai tuan tiieo cac tidu chuin TCVN 8219- 2009, TCVN 8218- 2009, TCVN 8228- 2009.
Cdc dcm vi cung i i i ^ \'at Ueu cho nha thiu thi cdng phai co cac chung nhan chit Iugng, chung nh$n ngudn gdc xuat xii ciia cac vat Ueu ma minh cung cap, tu dd lam cdn cii de nha thiu thi cdng quyet dinh lya chgn don vj se cung c ^ vat Udu.
Thuc td cho thay nhidu nhd thau tiii cong do mudn tiet ki^m chi phi (cuoe van chuyen, gia ti^inh vat lieu) ma lua chgn cdc dcm vi cung iing vat U^u khdng dap u i ^ dugc cdc tieu chuan chit lugng dd ra. Nhu \KC sii (hmg dd hoc khdng dii trgng lugng, khdng dii cuong do, lan nhieu da vyn; cat, da dam khdng du md dun do Ion, yeu cau ve cap ^xn hay )dn nhidu byi bin....ddn ddn chit lugng ke da xay khdng ddm bao.
3.1.3 Bienph^tM cdng
Bidn phap thi caig.neu khdng tuan tiiii theo diing cac q i ^ ttinh, qi^r i^iam se anh huong den chit Iugng cong trinh. Thi cdng ke bao vd mai de bidn cd tinh chit j ^ y thugc ill ldn ddn yeu td thiiy ^ ^ tiiity trieu. Vi vgy khi xay dyng trinh tu vd bim
^^bap thi fxxig ^m hidn quan tam ^n ydu td nay.
Vi dy nhu ]^iai lya chgn tiidi £ e m nudc thuy tridu k i ^ de thi cdng cac hang muc chan khay, chia thanh cac doan thi cdng tren toan t i ^ ^ de thi cdng cudn chieu, tan dyng thoi ^&n tiiuy Irieu kiet tiii cong chan khay ccoi khi tiiii}' tndu len co thd thi cdng [^lin tiian ke nam j ^ a tren muc nuoc, nhu
\ a>- dam bao tien do khdng bj gian doaiL 3. L4 Qudn ly, td chdc Ihi cdng
Cd thd Udt ke ra cdc van dd sau thugc ve qudn ly td chiic thi cdng khdng tdt din den khdng dam bao chit hrgng thi rang cdng trinh: Td chiic thi cdng chua tiieo diing quy tiinh quy fAam; khdng tidn hanh nghi?m tiiu kiem tra vat Heu san i M m
truoc khi dua vao sii dung; thidu cac nhan \iCT ky thuat cd chiic danh; cfaua ki?n toan dugc ehe dg, ttach nhian quan ly tai cac cip; xem xet [^ucmg an tiii cong d iu a diy dii; khdng nghian thu cac hang muc c « i g trii^ khuit va hang myc tnmg
^an; khi xay la su co con xem nhe, tham chi con ehe dau khdng xii Iy.
3 2 Nhdm cac yea to k h i c h quan 3.2.1 Yiu td khi hau
£>idu kidn tiidi tidt khic ngbi^ ciing anh huong den chit Iugng, tten do cdng trinh xay dung ke bikL Do anh huong cua s d i ^ gio dnh huong boi t h i ^ tridu nen viec thi cdng lat kho khan. Doi voi hang muc tiii cdng chan khay, mdi ke thuong chi tiii cdng dugc \'e d ^ khi tiiiiy trieu k i ^ Tien do thi cdng cac hang myc tidn rat it thdi gjan, mdi ngay chi thi cong dugc tu 5-6 tieng, moi thang chi tiii cdng dugc tu 7-10 ngay. Ddi voi cac hang myc ngam chim duoi nuoc thi phai dimg tiiiet In ndi de thi cdng, do tac dung ciia song gio tea vide dSnh vj. dn £ n h vi tri ihi cdng rat khd khan. Thiet bj, liiuong tidn chi tiii cdng dugc trong di«i kim sdi^g be, neu co song Ion tiii khdng thd neo dau thidt bi, phuong tioi thi c d i ^ dan d^ tioi dg ludn bj keo dai.
3.2.2 Dia chdt
E ^ chit cua khu vuc de bioi noi chui^ lit mdm yeu, roi rac duoi tac dyng cua song, gio, ddng chay....dan ( ^ dja chit luon co su bidn ddr^ [1].
Do khdng luoi^ hdt dugc su bidn ddng phuc \sp nay ndn khi tridn khai tiii cong tiiyc td phai chmh sua, fliay ddi cac phuang an xu ly ndn mong cdng trinh, bidn lAap thi cong, dan ddn anh huong din tien dg chung cua cdng trinh.
I ^ . GIAI PHAP ©AM BAO CHAT LlTONG THI CONG
4.1 Giai phap v^ cong tac due ciu kien be tong Van khudn ttudc khi sir dur^ phdi duoc lip ghep tiiu tiieo dung hmh dang, kich tiiuoc cac chi tidt ttong dd dn tiiiet kd. Sau do phai duoc su kidm tta n ^ e m tiiu cua Chu dau ur, Tu vin giam sat, Tu van tiiiet ke moi dugc sii dyng.
Can bg ky tiiuat. can b? giam sat phai theo doi chat Che cdng tac chuan bj, lip ehep .. in khudn ttuDc khi do be tong. Vj tti d§i \an kh.u.Sn dd dd 110 TAPCHIKHOAHPCVACONGNGHETHOYLOISO 26-2015
KHOAHOC •••i-lfHi'Hil-M
cau kien be ©ng phai that phing, ndn phdi chic chin, s£ich se. Lot bao tai duoi van khudn that phing, dam bao khi d|it van khudn len phai that kin kbit dd tranh mit nuoc. Khoang each giua cac bg van khudn phai ddm bdo khdng dugc sdt qua gay khd khan cho cdng tde thao do vdn khudn, ciing khdng dugc xa qua bat tidn khi van chuydn do be tdng va dam bd tdng. Khoang each bing tir 1,5-2,0 Idn bd rdng canh ben van khudn la hgp Iy.
Tnidfc khi do be tdng tidn hdnh quet diu thdi vao mat trong ciia van khudn. Cdng tac nay tuong ddi quan ttgng dd dam bao cac be inat cua ciu kidn dugc phdng nhin vd de dang khi thao da van khudn. Cdng tde nay cd the thuc hidn truoc hoac sau khi lap ghep vdn khudn.
Khi bd tdng khdi dd deit cuong dd tiiiet kd, dii thdi gjan theo quy pham hidn hanh Nha thiu moi tidn hanh thao da van khudn, giang chdng phyc vy cho h ^ g muc khde. Chat Iugng cua cdng tac vdn khudn se dugc kiem chiing khi dd xong cau kien be tdng co hinh deing dep, diing chat lugng, it ba via, mat be tdng nhan phing khdng phai td trat bit cii mgt chi tet nao.
4.2 Giai phap ve cdng tac do bd tdng cau kien Can bg ky thuat dugc giao phy trdch tai khu vyc thi cdng chu dgng kidm tra hi?n trang: Vj tri diing thao tde cua cdng nhan, thidt bj va anh sdng khi thi cdng ban dem, xe may thidt bj, dyng cy thi cdng ciia td san xuit, ehju trdch nhi?m truoc Ban chi huy cdng trudng vd chit Iugng san phim do td sdn xuit tiiuc hien. Thudng xuyen nhic nhd cdng tac an toan, yeu ciu ky tiiuat Wii thi cdi^. Cung ehju traeh nhi?m sdn phim voi td sdn xuat ndu san phim khdng dat yeu ciu. Phdi hgp vdi cdn bd giam sdt kidm soat chat ehe chit lugng tiu cdng, tidn hanh nghiem thu cac hang muc ydu cau. Khi xay ra sy cd, sai sdt vd chat lugng phai bdo cao ngay vdi Ban chi huy cdng tiuong, Tu van giam sdt dd thong nhit tim phuong an giai quyet. Trong trudng hgp can bg kj^ tiiuat, cdn bd gidm sat khdng cd m§t t ^ hien trucmg thi td trudng la nguoi ehju traeh nhidm cao nhat ve vide dam bao quy trinh sdn xuat, cung nhu cdng vide ciia td.
Mgt mat can bp ky tiiuat, cdn bd giam sdt tiieo doi kidm sodt chat lugng thi cdng chat ehe mat khac can bp ky tiiuat va td truong san xuit phai la
nhung ngudi true tidp quan ly va gjao due nang cao y tiiiic, traeh nhidm ciia cde thanh vidn lao dgng ddi voi chat lugng thi cdng cdng trinh. Phat huy tfnh tu giae, tu ehju ttach nhidm vd chit Iugng cdng viec ciia timg td va timg ca nhan trong td tiii cdng.
4.3 Giai phap ve cong tac thi cdng than ke 4.3.1 Gidi phdp ve cong tde thi cdng vdi dia ky thudt. lap dim dd ddm
Lop Igc bang vai dja ky thuat la mdt bg phan quan trgng dd ddm bao dn djnh ciia kdt cau mdi kd. De nang cao chat lugng thi cdng vdi dia ky thudt cdn:
- Vdi dja dugc sir dung phai c6 chiing nhan chat lugng tir nha san xuat, sau do Nhd thau phai mang di thi nghidm kiem dinh chat lugng cSn cu theo cac tidu chuan, quy pham hidn hanh. Sau dd nha thau phai moi Chii diu tu, Tu van thiet ke nghiem thu chiing lo£ii, chat lugng vai Igc, neu dam bao tiling ydu ciu chit Iugng dugc Chu diu tu, Tu van thiet kd cho phep tlti nha thau moi dugc dua vao sii dung xay dung cdng trinh;
- Truoc khi tidn hanh thi cdng ttai vai Igc phan dit mdng hang muc cdng trinh cd trai vai lgc phdi dim nen ky dat dung ttpng thiet ke, va phai dugc Chu dau tu, Tu vin giam sdt nghiem thu;
- Trai vai dja ky thuat thi cdng mai theo do an thidt kd, vdi dja ky tiiuat ti^ theo chidu tir chan len dinh mai, phan tidp giap giua 2 tam vai ^ a ky thuat chdng len nhau theo ydu cdu dd an dat ra;
- Thi cdng den dau ti^ vdi dja ky thuat ddn do, ttanh tm truac gay hien tugng sdng danh lam xd lech, va nhiet do mdi trucmg Iam hdng vai dja ky thuat. Vai dia ky tiiuat phai dugc trai cang deu, dugc nep voi mai dit bang ghim dinh tre dai 30cm, trdi du mdi dit phin dugc thiet ke, khdng CO hidn tugng cho cd cho khdng va tuyet ddi khdng lam djch chuyen phin vai dia ky tiiuat.
Ddi vdi cdng tac thi cdng lop dem da ddm lot, nhd tiiiu cin chii y:
- Trude khi thi cdng phan ddi da ddm lot phia tten, nha tiiiu phai tidn hanh nghiem tiiu phan tiai vai dja ky thuat bdn dudi;
- Da dam truoc khi tiii cdng phai dugc thi nghidni cip phdi, va dugc Chii diu tir, Tu vdn tiiidt ke
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I KHOAHOC j ^ E S a i B I t ^
ddng y vd chit lugng moi dugc sir dung. Thuc hidn rdi da dam lot bing tiiii cdng;
- Cdc ddng tap kdt da dam khdng dugc cdeh nhau qua xa dd giam tiiidu quang duong di chuydn cua nguoi lao ddng;
- Cd tiid tidn hdnh vira rai da ddm vira kdt hgp Idp dat ciu kidn be tdng. Rai da ddn ddu, san gat phdng se lip dat ngay ciu kien bd tdng den do.
Bien phdp nay cd uu diem : Dam bao ngay dugc cao trinh, vj tri cua cac ciu ki$n ghep kbit vao nhau; Trong qud trinh di chuyen vi chua rai da dam ndn se khdng cd hien tugng xd djch, chay da xudng duoi lam phia duoi day hon phia trdn;
ngodi ra cdn tranh dugc hien tugng sdng cudn ttdi da ddm gdy tiiit tiiodt. Tuy nhidn lai co nhugc didm la Idi6 kidm sodt chieu day cua lop da ddm cd ddng ddu va ddm bao tiiidt kd hay khdng. Vi vdy md can bd ky tiiuat phdi giam sdt eh^t ehe cdng tac nay.
4.3.2 Gidi phdp vi cdng tde thi cdng lap dgt cdu ki^n be tdng due sdn
Thi cdng lip ghep tir dudi len tren. Cac tim phai kbit nhau, tim np chdng ghe^ len tim kia chic chin. Bd mat cdc tim phai phing, dam bdo diii^
theo he sd mdi ke thidt ke. Trong qua trinh 1 ^ ghep trdnh va cham de gay hifn tugng niit, siit me tam. c i u ki^n ndo nhan thay khdng dat chat Iugng phai ydu cdu nhd tiiau thay the ngay truoc khi lip dat.
4.4 Giai phap ve cong tac to chirc nghidm thu cdng trinh
Nha thiu da ky hgp ddng voi trung tam thi nghidm cd du chiic nang thi nghiem bd tdng, cac chi tieu ca Iy, cap phdi...phuc vy kiem tra chit lugng cdng trinh ngay khi cd ydu cdu tir Chii diu
ttr vd Tu vin giam sat. Vi tuydn tiii cdng dai, so lugng ciu kien nhidu, nhidu ihao tac thi cdng nen dd ndng cao chit lugng cdng trinh tiu cdng tde thi nghi?m kidm (Snh chit lugng can phm thyc hifri thuong xuydn hon niia nhdm ban chd tdi da sai sdt trong thi cdng.
Can bd ky thuat hidn trucn^ la ngudi ehju traeh nhidm kidm tra theo doi viec thi cong diu tidn.
Ben canh dd Nha thiu cin bd tii cdn bd gidm sdt hien trucmg. Cac can bg ky thi4t va cdn bd giam sat hien trudng phai la nhiing ngucri eo chuyen mdn va nhidu kinh ngluem. Bidn phe^ kiem tra,
^ a m sdt la dung may trie dat, thude thep, kdt hgp sd lidu thi nghiem tinh todn cua don vj thi nghidm so sdnh vdi thiet ke.
Vide nghidm thu phai dugc tien hdnh nghiem tiic va cdn cii tiieo hd so thidt ke cdng tiinh, cac tieu chuin quy pham hien hanh ciia nha nudc va ghi vao bien ban nghiem tiiu cd cdc ben c i u ^ ky tdn.
Sau mdi hang myc hoac toan bg cdng trinh Nha thiu td chiic nghidm thu giai doan, todn bd cdng trinh va bdn gjao cdng trinh theo diing quy dinh ciia Nhd nuoc.
VI. KtV LUAN
Thdng qua thuc trang va tiiyc td thi cdng tien cdiig tiudng, tac ^ phdn tich cac nguydn nhan, cdc van de tdn tai anh huong khdng tdt ddn chit Iugng cdng trinh. Tir d6 de xuat mdt sd bi?n phdp nhim cdi thien vd ndng cao chit Iugng cdng trinh ciing nhu ndng cao cdng tac qudn ly chit Iugng thi cdng ke de bidn. Ddng tiidi vdi vide quan ly tdt chit lugng cho cac cdng trinh ke dd bidn tiii vide cd m^t tieu ehuin thong nhit trong tiu cong ke la mgt yeu cau cin thiet, lam co so danh gia chit lugng tfii cdng ciia mdi cdng trinh ke de bidn.
TAI LIEU THAM KHAO
[1] Phan Trgng Trjnh, Kiin tgo tre vd dja dpng luc hi?n dgi viing biin Vi$t Nam vd ki cdn 2012, NXB Khoa hpc ty nhien va cdng nghd
[2] Mmistty of Water, Land and Air Protection, Dike Design and Construction Guide Best Management Practices For British Columbia, 2003, Colder Associates Ltd. atid Associated Engineering (B.C.) Ltd.
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