CHNG I : CHNG M U

I.1. Bi lp rp ca cng Ph M

I.1.1 Mt bng bi lp rp

Mt bng cng Ph M trn v tinh

-Tng din tch ca khu cng l 129,790 m2 ,trong :

Kho hng: 35,250 m2, trong kho ngoi quan 18,000 m2. Bi: 30,000 m2, trong 14,500 m2 s dng cho kho ngoi quan Sc cha tng cng ca cc kho l: 150,000 MT Sc cha tng cng ca cc bi: 25,000 MT

-Kh nng chu ti nn kho bi: 35 MT/m2.

-c trng ca bn cng:

Chiu di bn: 200 m B rng bn: 28 m Cao trnh mt bn cng : +5.39 m Mc nc thp nht : -2.24m Cao trnh y cng : -9.3 m

-trn bi lp rp cn c cc trm in c th cung cp in nng cho hn 60 n v

hn(cng sut tiu th gn 500 KVA), ngoi ra cn c h thng chiu sang gm 6 ct n

cao p v cc h thng cung cp nc ngt, h thng thot nc, h thng phng chy

cha chy, c bit l h thng nahf xng ch to trc tip cc cu kin nh cc xng

ch to sn

I.1.2. Cc phn xng ch to

Phn xng ch to gm cc phn xng sau:

Xng lm sch sn ph v sn cc kt cu: kt cu c lm sch v sn ph nh ng, ng dn, dm va tm. Cc kt cu ny s c sn ph lp bn ngoi sau

tip tc sn 2 lp cn li. Sauk hi lp rp xong cc nt se c lm sch v

sn ln cui.

Khu ch to gi : nhng dm hnh v gc c s dng almf gi c thc hin trong xng ch ta thp. Tt c cc gi u c ch to ri y. Phn

thp s c ct ra bng cch s dng ca hoc dung hn hi oxy-acetylen ct.

Mi hn ni cc kt cu phi ph hp vi cc quy trnh c ph duyt. Kt

cu c lp rp v hn cng ti v tr t cng trnh.

Xng ch to tm kim loi v lan can: Nhng tm kim loi nh, bc thang, ai cng, ci kp c ch to trong xng ny. Nhng dm, rnh v mt ct gc s

c ct gt v ni di trong xng. Cu thang, thang ich ch ta trong mt khu

vc ring bit ca xng.

Xng ch to ng: Xng ng c s dungjc h to cc ng bao gm ct, bo mn, hn v kim tra khng ph hoi ca mi hn . Cc ng thp sau khi c

sn xong s mang ra khu vc rieng bit trong kho cha sp thp ti xng.

I.1.3.Khu vc lp rp v ghp ni

Cc ng thp sau khi c ch to, kim tra khng ph hoi theo tiu chun v thc hin

ct gt, sn ph, sn trong xng lm sch b mt sn. Cc ng thp sau khi c sn

xong s c mang ra khu vc lp rp.

Khu vc lp rp v ghp ni bao gm nhiu kho khc nhau:

Kho ch vt liu thp v khu cch ly

Kho tm Kho chun b ct, lm sch v sn Xng ch to kt cu Cng ch to v han ng.

I.2.Cc thit b phc v thi cng

I.2.1 Cc loi my mc v thit b thi cng trn b.

Bng I.1. Cc thit b phc v thi cng

m t loi thit b nc sn

xut ti nng ln

nht chiu di cn (m)

s lng

cu KOBELCO JAPAN 550 T khng

Jib 108

SL6000

TEREX U.S.A 70T 36

T775

(Waverly)

SS 500 JAPAN 45T 39

(KATO WORK)

Bng I.1. Cc thit b phc v thi cng

m t loi thit b nc sn

xut ti nng ln nht

chiu cao nng (m)

s lng

xe nng crane-forklift JAPAN 5T 4

TCM TCM 50

TCM 20T 3

FD200

bng I.1> cc loi my mc phc v thi cng

m t tn thit b v cc thng s k thut

cc thng s s lng

cc my hn Arctronic 426

thit b t sy (Dry oven) YCH-300T1

dng in

phc v

220V,50-60Hz

cng tc

cng sut 5,8KW

hn

kh nng cha 300kg

nhit ti a 400 C

t Weld bank-YCH 200 dng in

cc

thit b phc v cng tc

hn

220V,50-60Hz

cng sut 3,3KW

kh nng cha 200kg

nhit 50- 400 C

phch hn TRC-5K (Electrode

Dryer) dng in

220V,60-100Hz

cng sut 300W

kh nng cha

5kg x450mm

nhit 80- 100 C

cc m ct tay cm TANAKA HC 391

thit b MY CT NG BNG XCH MY

phc v my ct tn t ng CNC HVR 6125

hng sn xut

cng tc

ct ERMAK SANMAKINA

SANAYI TIC.Ltd

ct c thp dy 25mm

di 6.1m,

tc 3-5 psc

trng lng 68,5 T

cng sut moto 45 KW

dng in 380 V

kch thc my

2480x8000x3390mm

dng in tk 125A

my ct t ng Pro Arc Master

my ct Profile

I.4.S liu cng trnh

Dn khoan la loi dn nh dng BK c thp khoan, cng tc khoan s do dn khoan t

nng thc hin.

Dn dc thit k di dng kt cu thp khng gian bng thp vi mt mt thng ng,

c cu to t cc loi thp ng cso ng knh khc nhau.

Dn dc thit k vi 12 u ging khoan.

Kt cu KC dn l dng kt cu hnh thp khng gian dng 4 ng chnh, n c mt mt

phng thng dng v 3 mt cn li nghing, c chiu cao l 56,1 m.

C 4 mt ngang D1, D2, D3, D4

Mt ngang D1 cao (+) 5,0 m.

Mt ngang D2 cao (- ) 11,5 m.

Mt ngang D3 cao (- ) 28,0 m

Mt ngang D4 cao (- ) 47,1 m

KC lin kt vi t nn thng qua h thng mng cc, gm 4 cc chch c lng vo

trong 4 ng chnh, n c ng xung t. Khi chn c chng n mn bng

anode hy sinh.

M hnh Sap ca khi chn

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12

CHNG II: GII THIU CC PHNG N THI CNG V LA CHN

PHNG N THI CNG

II.1.Cc phng n thi cng trn b.

Cc phng n thi cng trn b hon ton ph thuc vo din tch bi lp rp,trang

thit b

V phng tin thi cng hin c trn bi lp rp ca cng ty.

II.1.1.Phng n thi cng ch to nt.

L phng php ch to sn c nt ca KC trong nh my, sau khi ch to xong

cc nt ca KC trong nh my ngi ta tin hnh vn chuyn cc nt ra bi lp rp

bng xe nng hoc cu Loi nh.

Cc nt ny c t ln trn h thng cc gi c thit k v lp rp trn

bi lp rp.

Sau khi c nh cc nt trn h thng cc gi ngi ta tin hnh ch to cc

phn cn li ca khi chn theo thit k.

u nhc im ca phng php ny:

a, u im:

u im ln nht ca phng n ny l c th ch to ton b cc nt ca KC

trong nh my v vy ta c th kim sot c cht lng cc mi hn ca nt, hn na

kt cu c chia nh do vy ch cn dung cc thit b nng, cc loi cu nh phc v

cho qu trnh thi cng KC m khng cn dng n cc cu ln.

b, Nhc im:

Do lp rp bng phng php ch to nt nn s lng cc mi hn tng ln rt

nhiu, cc khi lng cng vic thc hin ngoi bi lp rp nhiu, do vy m chi ph

v kim tra, kim sot mi hn kh khan tn km khi lng cc cng vic thi cng

trn cao nhiu

Phng php ny nhm c chnh xc ha trong qu trnh ch to chn song n

khng cn ph hp na l do nhc im nu trn. Do phng php ch to nt

c thay th bng phng php khc.

II.1.2.Phng php thi cng p mi

Thi cng KC bng phng php p mi l phng php ch to sn 2 panel di

t,mt Panel c ch to ngay trn ng trt Panel cn li c ch to ngay v tr

cnh ng trt,sau khi thi cng xong Panel trn ng trt, ngi ta tin hnh lp

dng cc thanh xin khng gian ca 2 Panel.

Sau khi lp xong cc thanh khng gian ca 2 Panel bn th tin hnh lp cc mt

ngang.

Sau cng l dng cu cu nhc Panel cn li ln v p n xung ri tin hnh hn

c nh Panel vi cc thanh ngang, thanh xin v mt ngang.

Tip theo l tin hnh lp t cc kt cu ph ca KC nh sn chng ln,cc

anode hi sinh, cc ng dn hng

a, u im

Thi cng ch to KC theo phng php ny chng ta tit kim c din tch

ch to, tn dng ti a khng giant hi cng khi m din tch bi lp rp hn ch.

S lng mi hn gim nhiu hn so vi phng php ch to nt nn kim sot

mi hn tt hn Tin thi cng nhanh hn phng php ch to nt.

b, Nhc im

Phi thi cng iu kin trn cao,c bit l phi hn cc thanh khng gian ca

2 Panel bn trn cao, do cht lng cc mi hn kh kim sot c, h thng gin

gio cng nhiu, mc an ton cng kh kim sot hn, mt khc khi cu lp rp cc

thanh khng gian v cu lp Panel trn cng phi dng cu ln,thi giant hi cng ko

di, tin chm.

Thi cng phng n ny cng khng to c hiu qu kinh t cao m ngi ta

ch p dng bin Php thi cng ny khi bi lp rp b hn ch v KC nh.

II.1.3 Phng php thi cng quay lt Panel

Thi cng ch to KC theo phng php quay lt Panel l thi cng ch to trc

cc Panel bi lp rp trn h thng gi sn c thit k

Sau khi ch to xong cc Panel, tin hnh quay lt Panel a Panel v v tr

thng ng ri lp rp cc mt ngang. Sauk hi lp t xong cc mt ngang th quay lt

Panel khc v hn lin kt vi phn KC trc .

Tip t cc khng gian ca cc Panel.

Sau tin hnh lp rp kt cu ph tr khc ca KC nh sn chng ln, cc ant,

cc ng dn hng, cc padeye

a, u im

C nhiu cu kin ca KC c lp rp ch to di thp,vic ch to KC d

dng hn nh s dng cc tram t hn t ng, cc cng tc ct ng v ch to ng c

ch to ti cng trng c th ch to nhiu cu kin cng mt lc, do vy c th y

nhanh tin b cng trnh ng thi c th tn dng ch to ti a my mc v nhn lc

vo cng vic .

H thng dn gio phc v thi cng cng hn ch cng tc kim tra kch thc v

kim tra cht lng cc mi hn c kim tra tt hn

C th p dng cho cc cng trnh ln nh khc nhau.

Cng tc an ton c m bo hn do lm vic di thp.

Mang li hiu qu kinh t cao.

b, Nhc im

Cn cc thit b cu nng ln.

H thng gi chng phc tp.

Cn mt bng rroongj thi cng.

II.1.4.Phng n thi cng c la chn.

t cc u nhc im ca cc phng php thi cng KC phn tch trn v c

im khi lng ca khi chn th ta nhn thy rng KC thi cng theo phng php

quay lt panel s mang li hiu qu kinh t cao nht v c bit n rt ph hp vi cc

thit b,my mc v mt bng bn bi ,do vy ta la chn phng php quay lt panel

thi cng KC trn bi lp rp.

c im:

- s lng mi hn di thp:

- s lng mi hn trn cao:

- trng lng 1 panel:

- trng lng khi chn : ,nn ta phi h thu bng cch ko trt phi thi

cng lp dng ngay trn ng trt.

II.2 cc phng n thi cng h thu.

Ph thuc vo phng tin vn chuyn v phng n vn chuyn chn,ph thuc vo

trng lng KC v kh nng ca phng tin thi cng.

II.2.1 phng n ko trt KC xung h thng poton.

KC c ch to trn ng trt v t trn cc mng trt.KC s c ko trt

trn ng trt xung ln poton hoc s lan mt boong bng cc h thng ko trt.

a, u im.

H thu KC bng phng php ny th khng cn dung n cu ni ,ch cn h thng

ti ko bng sc ko ca cc cu DEMAG CC4000 V DEMAG CC2000.thch hp

dung cho KC c kch thc v trng lng ln

b, nhc im.

H thu KC bng phng php ko trt c nhiu nhc im , l phi thit k ch to h thng cn y rt phc tp v tn km,thit k v b tr h thng h th,thit k h

thng ti ko rt phc tp,s dng nhiu loi cp t tin,thit k h thng mng trt. c bit l qu trnh a KC ln h thng poton rt phc tp v tn nhiu thi gian.

II.2.2 Phng n dng cu nng h thu khi chn xung S Lan.

KC c ch to trn bi lp rp v t gn mp cng.Dng cu ni nng KC ln v

t ln s lan.

a, u im.

Phng php h thu bng cu ni ny c thc hin rt n gin v thun li, ng thi qu trnh h thu din ra trong thi gian ngn,tit kim c thi gian v nhn lc

ng thi tn dng c thit b my mc c sn ca VSP nh cu ni Trng Sa,Hong

Sa.

H thng bm dn nc vo s lan cng c kim sot 1 cch n gin hn.

b, nhc im.

Nhc im ln nht ca phng php ny ch l h thu c nhng KC c khi

lng nh hn 1200T,cn nhng KC c khi lng ln hn th khng th thc hin

bng phng php ny th phi i thu cu ni ca nc ngoi c sc nng ln hn th rt

t tin,tn km nn khng hiu qu v kinh t.

II.2.3 phng php dung xe trailer h thu xung s lan.

y l phng php kh ph bin trn th gii trong vic h thu,nhng mi c p

dng Vietsopetro t nm 2003.

Vic ch to v hon thin khi chn c to nn cc dm v vn chuyn ln S

Lan.

KC s c t ln trailer thng qua cc dm v c vn chuyn ln S Lan.

a, u im.

Vi phng php ny th c th p dng thi cng cho bt c KC no cng k c cc

KC c khi lng ln nh MSP,CTP

Qu trnh h thu cng ht sc n gin v din ra trong thi gian ngn.

b, nhc im.

H thu KC bng phng php ny c s hn ch l vic kim sot s cn bng ca

S Lank khi xe trailer di chuyn a KC xung S Lan,h thng bm dn nc phi

c tnh ton thit k ht sc chnh xc.

II.2.4 Phng n ko trt khi chn xung S Lan.

y l phng n s dng ng trt v thit kich thu lc (Strand jack hoc cu)

ko a KC xung S Lan.Cc bc h thu nh sau:

- Bc 1: a s lan vo v tr,neo gi c nh theo thit k.

- Bc 2: mc cp,puli vo cc v tr tnh ton ca KC.

- Bc 3: dn dp chng ngi vt trn ng di chuyn ca KC,bi m ln

ng trt.

- Bc 4: Ko KC ra mp cng,dn nc cho s lan.

- Bc 5: Cn chnh s lan,tip tc ko KC xung s lan.

- Bc 6: sau khi di chuyn KC ti v tr cui cng tin hnh lin kt cng KC

vi s lan,bm nc dn trong s lan ra.

- Bc 7: dung tu ko ko s lan v KC ra v tr neo u ch ngy ko ra v tr

xy dng.

Phng n ny dung cho nhng chn ln c khi lng ln khi kh nng cu nng

khng cho php.

II.2.5 Phng n thi cng h thu c la chn.

T vic phn tch cc u nhc im ca phng php thi cng h thu th ta nhn thy

rng KC c khi lng nn n thch hp thi cng h thu bng phng php ko

trt khi chn xung s lan.Mt khc y l phng n thi cng c ch inh

trong n.

II.3. Cc phng n thi cng nh chm KC

Cc phng n thi cng trn bin ph thuc vo phng tin vn chuyn KC ra ni xy

dng, ph thuc vo phng php thi cng trn bin hin c ca cng ty ti ni xy dng

cng trnh, trng lng ca KC

II.3.1. Phng n nh chm KC t s lan bng bn xoay

Trn s lan ch KC c h thng bn xoay.

Sau khi neo gi s lan ti gn v tr xy dng cng trnh, cc giai on nh chm dc

thc hin nh sau:

Giai on 1: Ct b cc lin kt gia KC v s lan.

Giai on 2: Dn nc vo pha bn xoay ca s lan to mt nghing theo

nghing thit k.

Giai on 3: S lan t trt i trn bn xoay nhng trng tm ca n cha n

trng tm bn xoay..

Giai on 4: Trng tm KC nm pha bn ngoi bn xoay khi KC s t

trt xung bin.

Giai on 5: KC ri khi bn xoay lao xung bin, di tc dng ca lc y ni

KC s t ni ln va xoay v v tr cn bng (nh chn nh hn s ni dn

ln, cn y ca KC nng hn s chm xung v chn xoay dn v vj tr thng

ng).

II.3.2.Phng n nh chm KC bng cu ni.

Sauk hi neo gi s lan ti gn v tr xy dng cng trnh, cc giai on nh chm dc

thc hin nh sau:

Giai on 1: Gii phng cc lin kt gia khi chn v s lan cho mc cp ca

tu cu vo cc v tr theo s tnh ton sn.

Giai on 2: H thp KC xung nc cho ti khi cc cp treo trng th thi,

kim tra t th ni ca KC.

Giai on 3: Quay chn ln theo phng thng ng bng cch thu cp nh

KC v ni cp lin kt vi y chn , Qu trnh quay lt ca KC phi c

tnh ton cc v tr gc quay khc nhau v ni khi lng, ph tm, trng tm

ca KC. Khi khi chn quay lt hon ton th kim tra KC chon gang bng.

Nu KC b lch th phi tnh ton khi lng nc dn vo cho cn bng.

Giai on 4: nh v khi chn chnh xc ti ni xy dng cng trnh.

Thi cng nh chm KC theo phng php ny c rt nhiu u im, l qus

trnh thi cng rt n gin v din ra rt nhanh, c th hn ch ti a cc s c i

vi KC v rt an ton.

Nhc im cu phng php nh chm ny l khng th thi cng c nu

khng c cu ni ln.

II.3.3. Phng n thi cng nh chm c la chn.

T vic phn tch cc u nhc im ca phng php thi cng nh chm th ta nhn

thy rng KC c khi lng khong nn thch hp thi cng nh chm KC t s lan

bng bn xoay.

Kt lun: Cc phng n thi cng c chn l:

Thi cng KC trn b theo phng n quay lt panel.

H thy KC xung s lan theo phng php ko trt.

Vn chuyn KC trn s lan ra v tr xy dng bng tu ko dch v.

nh chm KC t s lan bng ng trt.

CHNG III: QUY TRNH THI CNG

III.1.Quy trnh ch to v lp dng

Cng tc thi cng ch to

Quy hoch bi

lp rp

Chun b

nhn lc

Chun b

my mc Chun b

vt liu

Gia cng ch to

Ch to cc khi b tng

neo gi cc panel

Tp trung vt liu ch to

mng trt, gi , ct ng

B tr gi v ch to

launch truss L1 B tr gi v ch to launch

truss L2

Quay lt launch truss L1 sau

di chuyn ti v tr ng

trt v c nh bng h

thng t chng

Ch to conductor frame cao

trnh +5m; -11,5m; -28m; -45,6m

Lp t cc conductor frame ch to vo

launch truss L1

Quay lt launch truss L2 sau i chuyn ti

v tr ng trt, hn c nh vo cc

conductor frame

B tr gi v ch to Row A

Lp t phn ni di ca cc mt

ngang cc cao +5m; -11,5m; -

28m; -45,6m. Lp t cc thanh cho

ca Row 1

Quay lt Row A di chuyn ti v tr

hn vo cc mt ngang Ch to Row B

Quay lt Row B di chuyn ti v tr

hn vo cc mt ngang

Ch to mt ngang cao trnh +5m,

cc kt cu ch K ca mt ngang

cc cao -11,5m; -28m v phn cn

li ca mt ngang cao trnh -45,6m

Lp t mt ngang cao trnh +5m v lp

t hon thin cc mt ngang khc

Lp t cc thanh cho ca Row 2

Lp t cc kt cu ph tr, tin hnh cng

tc sn.

Hon thin khi chn chun b h

thy

III.2. Quy hoch mt bng thi cng

Mc ch: Quy hoch mt bng thi cng sao cho phi ph hp vi iu kin din

tch m bi lp rp hin c v sao cho thun tin nht vi phng n thi cng

chn, nhm gim ti a vn chuyn cc cu kin i xa, gim ti a vic di chuyn ca

cc loi xe, cu, hay vic di chuyn ca cc b phn cng nhn, nhm nng cao hiu

qu lm vic, gim chi ph v c hiu qu kinh t nht. B tr mt bng ca khi chn

c th hin trn s .

Mt s vn cn lu khi quy hoch mt bng thi cng trn BLR:

- Trc khi tin hnh xy dng ngi ta lp hng ro xung quanh v tr thi cng,

lp t cc bin bo, cc k hiu cho phng tin vn chuyn i li trong khu

vc thi cng, bin bo phng nhng ni c vt nguy him d gy pht n,

v cm nhng ngi khng c nhim v i li khu vc thi cng

- Khi chun b thi cng, tin hnh cng tc kim tra mt bng bi lp rp, kho

st o c ton b h thng mt bng khu vc cn thi cng. Xc nh ng di

chuyn ca cu, mt bng bi nm trong khu vc cu di chuyn phc v cho

vic quay lt Panel, phc v cho xng tc h thy khi chn .

- Gii phng ton b trang thit b vt t khng lin quan n qu trnh thi cng

khi chn .

- Vt t phi m bo yu cu v s lng, cht lng v c vn chuyn n

ng ni quy nh, m bo yu cu ca thit k k thut v thit k t chc

thi cng.

- Cng tc a vt t ra bi theo quy hoch c th hin bn v quy hoch

bi lp rp.

- Sau khi chun b cc nguyn vt liu v a cc thit b n cc khu vc trn

bi lp rp, tin hnh cng tc hun b chung cho vic quy hoch bi lp rp.

- nh du khu vc lp rp cc Panel.

- Lp t cc gi ch to Panel. Vic lp t kim tra cc gi c tin

hnh nh cc thit b my mc k thut theo ng cc quy nh v an ton.

- Trn ng di chuyn ca cu phi c tin hnh kim tra 4 n 5 ln trc

khi vn hnh, c th xc nh c khong khng gian cn thit phc v

cho cc hot ng ca cu, kim tra cc c tnh k thut b mt BLR nh:

cng b mt, dc b mtvv, t c nhng bin php tch cc chun

b cho cng tc thi cng, trnh c nhng s c c th xy ra trong qu trnh

thi cng, m bo tin thi cng cng trnh. Trong thi gian thc hin cc

thao tc, yu cu v dc, mt bng khu vc hot ng ca cu DEMAG

khng vt qu 1/300.

- Kim tra (trong trng hp cn thit phi sa cha) cc trm pht in, cc h

thng k thut, n pha, cc thit b hn ct hi v k thut phc v nng ti

(cp, cu,mc ).

- Vn chuyn n cc khu vc thi cng trn bi lp rp cc dng c v thit b

phc v thi cng (Cc bnh Oxi, Axetylen, cc in cc, vt liu bi trn, ct

thch anh, cc vt liu sn, cc b phn ng).

- Cc tuyn giao thng cho cc phng tin c gii v ng di chuyn ca cu

phc v lp rp phi c kim tra, thu dn ph hp vi yu cu k thut ca

cc phng tin co gii, cu, xe ti vn chuynphc v thi cng.

III.3.Cng tc chun b vt t, my mc.

III.3.1. Tip nhn vt t v bo qun.

Cc ng nhn phi c kim tra theo tiu chun API-RP-2B. Phn loi sp xp theo

ng knh, dy, cc t ch to c dnh s hiu c th

ng khng c chng ch phi c xp ring, vic nhn ng ch cho php sau khi c

chng ch.

Trong vic bo qun ng khng c ko trt ng, gy ra cc vt un, lm mo ng,

trnh hi m tp trung trn b mt ng. Nht thit phi dung cacs hm ng v h dm

ngang ng.

Trc khi a ng vo thi cng phi lm sch bi g, cc lp g st ngoi thnh ng

bng phng php my nn kh v phng php nh giy nhm.

Gi k t ng bng b tng hoc g. Yu cu t ng cch mt t ti thiu l

100mm, i vi ng >610mm cho php k chng ln nhau khng vt qu 3 hng, cc

loi ng khc ng knh nh hn khng cho php xp qu 5 hng.

- i vi thp tm:

Yu cu i vi cc tm k l g hay b tng ( i vi cc tm u tin) vi

cao m bo ln hn 100mm. T lp th 2 yu cu k cao ln hn 400mm.

- Thp ch I:

Xp t th tnh, cnh dm tip xc vi gi k l nn b tng cng hay si

c gin bng phng. Khi sp xp phi ch to ra dc m bo nc

khng b ngng ng, gy nh hng ri cht lng ca thp.

III.3.2. Chun b cp, dy thng.

Trong cng tc thi cng khi chn , vic lp dng cc phn cu kin to thnh mt

chan hon chnh thng qua cc qu trnh cu lp. Vic cu lp phi tht tuyt i an

ton trnh cc trng hp c s c xy ra. Cp l mt thit b quan trng trong vic di

chuyn, ko buc cc vt nng, cht lng cp lin quan mt thit vi s an ton cu thit

b cng trnh v tnh mng con ngi, do vy vic chn cp phi tin hnh ht sc

nghim ngt. Trc khi thi cng mt cng trnh ngi ta phaiar kim tra cc loi vt liu

nng theo ng tiu chun quy nh nh sau:

Ch c nhng ngi c tay ngh, qua vic st hch v an ton lao ng, an ton v

in v phng chng chy n mi c giao nhim v iao bn cp.

Vic bn u cp phi tun th theo cc iu kin k thut theo tiu chun quc gia

TCVN 4244-86.

Cp xut xng phi c ng mc theo di, c kim tra cht lng, cso km theo

chng ch cht lng v bin bn th ti.

Qu trnh kim tra s b:

- Kim tra cp giy chng ch cht lng gm: Cp trc khi em bn phi cso

chng ch cht lng bao gm: xut x, quy cch cp, lc ko t v ghi vo bin

bn.

- Kim tra bng mt: Vic kim tra bng mt nhm loi b nhng on cp c

khuyt tt nh xon, vn, gp, t tao ca cp hoc han g

Ch : ch khi hai bc trn hon tt mi thc hin cc cng vic tip theo.

- Cng tc ct cp khi cun: Cp c ct khi cun bng cc phng php cht,

ct hoc ct bng in. Trong trng hp ct bng hn, in cc th 2 ca cc

thit b hn phi c ni st ngay v tr ct (

Thi gian th: 3 pht.

- Cng vic th ti tin hnh vi 2 loi sau:

Loi 1:th cp c ng knh nh hn 22: ta dung cn tc mc trc tip vi vt

nng c trong lng bng ti trng th thit k.

Loi 2: th cp c ng knh ln hn 22: vic tin hnh th cp c tin hnh

trn gi thy lc 1500T. Lc ko c tnh ton chuyn i t p sut trong si-

lanh sang quan st tr s ng h p lc.

Cp lm xong phi c bo qun tren gi tr chuyn dng, khng c t ngoi

tri hoc ct bi bm vo. Gi bo qun phi c cch li vi ni m t hoc

nhit cao. Mi mt loi cp phi c km theo chng ch cht lng v bin

bn th ti.

Cp ly theo tiu chun ca API loi 6x37FC.

Tnh ton cp vi h s an ton K=6 vi cp c ti nh hn 100T, K=4 vi cp c

ti ln hn 100T.

Ghi ch: H s an ton i vi dy thng ly bng h s an ton ca cp. Tnh

ton sc cng c dy treo da theo h s sc cng T ca cp.

III.3.3.Cng tc chun b cho hn.

- Bo qun vn liu hn:

d tr dy thp hn, que hn cn phi c nh kho ph. Trong cn b

tr l sy bo qun cc thit b hn. Nhit trong nh kho ph khng

c thp hn 17 C. Trong nh sy phi b tr thit b lm sch dy

thp hn b g, c dnh du m hoc cc vt bn trc khi cun thnh cun.

bo qun vt liu hn d tr ngay trn bi phi c cc kho cha ph, t

sy que hn. Nhit nung nng que hn c xc nh theo cc thng s

cho.

Cc que hn c bo qun theo tng loi mc, theo tng thi gian sn xut

v ng knh que hn. Trong t sy, que hn c t trn gi cao c ghi

m hiu, khng c cha ng nhng que hn khng cng chng loi vo

cng mt thng. Que hn trc khi s dng phi dc sy nhit cao,

ch sy phi tun theo cc s liu c ghi trong l lch que hn.

Que hn sy mi ln giao cho th hn s lng cn hn trong na ca lm

vic. S que hn khng dung n cui ca, th hn phi cho vo t sy.

Thit b hn dung thi cng ti cc bn bi khng c mi che th phi t

trn cc lu di ng v cc bng in ng lc, cu giao v cp, chng

c ni vi cc ni tiu th theo cng sut c ghi.

- Yu cu khi s dng cc vt liu hn thit b hn:

Khng c php s dng cc vt liu hn khi kim tra chng ch thy

cha ph hp vi tiu chun v nhng iu kin k thut ca chng.

Tt c cc thit b hn phi dc kim tra m bo vn hnh tt v ng

theo s liu ghi trong l lch.

Loi que hn thng dung cho cng trnh trn bi l: LB-52U,

KOBELCOL, B-52KOBELCOL.

C que hn c s dng c 3 c: 2.6,3.2,4.0mm.\

Dy thp hn phi trong cc cun dy, mi cun dy yu cu phi c

nhn hiu, m l hng

Trc khi hn, dy thp phi c lm sch vt g, bi v du m.

Trc khi s dng bt hn, nht thit phi sy nhit t 300 C n

400 C trong 1-2 gi. trnh dnh kt trong thi gian sy, phi o cht

tr dung bng xng.

Khng lm pha trn vt liu khc vo cht tr dung, lng m chat tr

dung khng c qu 91%.

Trc khi a ra s dng li cht tr dung phi dc di u v sy nng.

- Yu cu i vi th hn:

Cc th hn ny phi qua cc lp chuyn mn cho tng quy trnh hn

c kim tra cp chng ch cho tng quay trnh hn .

Th hn c cp chng ch cho tng loi quy trnh hn khi qua lp

hun luyn hn, khi chuyn sang quy trnh hn khc th phi tip tc tham

gia cc lp hun luyn v quy trnh hn v c kim tra cp chng ch

hn.

- Cc mi hn th phi c qua kim tra. Cng tc hn c kim tra v gim st

theo tng lp hn, sau khi kt thc ng tc hn vic kim tra cc mi hn c

tin hnh nh sau:

Kim tra bng mt thng sau khi khng pht hin ra khuyt tt s chuyn

sang kim tra bng phng php khng ph hy (NDT).

Ty theo tng chiu dy ca kim loi hn c bn v c tnh quan trng ca

kt cu m trc khi kim tra bng phng php khng ph hy phi

cho kim loi c thi gian phcuj hi cu trc kim loi c th gm 2

loi: kt cu chnh s c thi gian ngh lu hn 48 gi, kt cu ph thi gian

ln hn 24 gi.

- Sa cha cc khuyt tt hn:

Sau khi kim tra cc mi hn m pht hin ra cc khuyt tt hn th tin

hnh khc phc v sa cha.

Ranh gii ch hng cn ddowcj ngi kim tra nh du v xc nh chnh

xc.

Kch thc cho php ca cc on khuyt tt ca cc mi hn ng c ghi

trong ccs quy phm tnh ton cc mi hn.

Chun b sa cha cc khuyt tt ca mi hn phi c tin hnh di s

hng dn ca cc chuyn gia v chnh k s hn.

Sa cha khuyt tt bn ngoi trc khi tin hnh chiu chp, hoc siu

m.

Cc vt nt phi c xa b cng vi cc ng hn k cnh, sau nht

thit phi lm sch v xem xt li, vic ny phi do th c kim tra. Sauk hi

lm sch, on ng phi c hn li v tip tc tin hnh kim tra cht

lng.

Cc vt nt ming hn phi ph b v hn li ming hn.

Cc on mi hn c bt kh, c x hn v cc khuyt tt khc nht thit

phi ph i hn li.

Cc on hn cha su v cha nng chy dc rnh phi ph i

hn li, tip nht thit phi lm sch b mt. Dc cung hn nht thit

phi ty lp cha nhiu Cacbon ti su quy nh l 2mm.

Sa cha ti mi ch khuyt tt khng c qu 2 ln.

Nu s xut hin khuyt tt trong cc mi hn mang tnh cht c h thng

th ph ngng qu trnh hn cho n khi lm r nguyn nhn gy ra khuyt

tt, vic hn ch c tip tc khi khc phc c nguyn nhn gy ra

khuyt tt. Ph b on c khuyt tt phi tin hnh bng my mi hoc

thi sch bng Cacbon.

III.4. Thi cng trn b

III.4.1.Ch to mng trt.

Mng trt c ch to ngay ti cng trng, khi ch to chia lm nhiu on ngn.

Sauk hi c ch to xong vn chuyn ra ng trt v hn vi nhau.

III.4.2. Ch to ng nhnh.

Tt c cc ng ch to ng nhnh s c gia cng trong xng. Cc trm hn h

quang c b tr trong xng iu khin gi cc on ng nhnh c chiu di khc

nhau.

Sau khi hon thnh cng tc DC/NDT cc thanh c vn chuyn n bi lp rp.

Tt c cc thanh cc mt ngang s c lp rp trn bi lp rp.

III.4.3. Ch to ng chnh.

Cc ng chnh s c t hp trn bi lp rp t nhiu on ng v c kim tra gim

st cht ch. Cc on ng ca ng chnh c ch to trong xng, vn chuyn ti bi

lp rp bng cc xe chuyn dng.

III.4.4. Ch to Conductor frames.

Conductor nn c ch to chiu di theo thit k. Sauk hi hon thnh vic kim

tra DC/NDT, cc conductor s c vn chuyn ti v tr h thy bng cu.

III.4.5. Ch to cc kt cu ph tr.

Gi cp tu, gi chng va p, bo v Riser, cc on cc chuyn tip v mt vi kt

cu khc nh kp Riser, tay vn cu thangs c ch to song song trn bi lp rp.

Sauk hi hon thnh cng tc kim tra DC/NDT v tin hnh sn nhng kt cu ny v

sau cu n v tr lp dng.

III.4.6.Ch to cc gi .

m bo cho cng tc thi cng lp t cc b phn kt cu ca khi chn , cc b

phn kt cu n nh v phc v cho qu trnh quay lt Panel, th phi tnh ton v ch

to mt s gi . Tt c cc gi c cu to sao cho phi m bo kh nng chu lc

do ti trng cu kt cu truyn xung trong tng giai on thi cng khi chn . Ty

thuc vo quy trnh thi cng v lp t. i vi quy trnh ch to khi chn th tng

ng vi tng giai on ch to v s c nhng on gi khc nhau.

- KC c 2 loi gi sau:

Gi xoay K1

Gi K2

a)Gi ng xoay K1.

L loi kt cu c cu to bi hai ng lng vo nhau, ng nh hn c kch thc

(610x15.9) ,lng vo ng ln c kch thc (711x15.9) c hn c nh li vi nhau

bng 4 tm thp bn. Mt trn c cu to dng khp l 1 mng thp c ng knh trong

l 1392, mt di l mt bn thp chu lc c kch thc 30x1400x2000, chiu cao ca

gi l 1104mm.

b)Gi ng K2.

L loi gi ch s dng cc ng nhnh trong khi t hp Panel v lp dng KC.

V mt kt cu th K2 hon ton tng t nh loi gi ng chnh c trnh by

trn, gi K2 c din tch tip xc t nn nh hn K1 (1000x1000)mm, phn trn

khng phi l cu to dng khp m n l mt tm thp phng c kch thc

(20x600x600) mm n c t ti cc v tr ca cc ng nhnh v k trc tip ln t nn.

Chiu cao ca gi K2 l:

III.4.7. Ch to cc thanh chng tm thi.

Phng php ch tqaoj KC la chn l phng php quay lt Panel v vy khi

quay lt cn nhng thanh chng , gi cac kt cu ti ng v tr thit k ca n.

chn ny s dng 2 t chng tam gic gi cho Launch truss, cac phn ca mt Row

nm ng v tr thng ng, phc v cho qu trnh lp dng.

III.5.Quy trnh thi cng h thy khi chn xung s lan.

III.5.1.chun b thit b vt t v phng tin h thy.

III.5.1.1. Thu dn mt bng bi lp rp.

Tin hnh thu dn ton b cc trang thit b v vt t tn bi lp rp bng cc phng

tin nh xe nng, cuDi di tt c cac chng ngi vt nm trn bi, thit lp hnh lang

an ton t v tr ch to KC ra n mp cng. Lp t cac h thng m tu vo v tr

mp cng m s lan s cp .

Chun b v kim tra kch thc cu s lan theo cc yu cu ca bn v k thut, tin

hnh ch to v hn cc lin kt gia gi v s lan KC.

III.5.1.2.Chun b cc phng tin thi cng h thy KC.

Cc phng tin h thy KC bao gm c:

+S lan vn chuyn S45 c cc thng s k thut sau:

- Chiu di: 180m.

- Chiu rng: 42m.

- Trng lng: 27000T.

- Mn nc ln nht: 8.5m.

+Mng trt:

- S lng: 2

- Kch thc: bng chiu di ca thanh Launch truss.

- V tr: b tr trn sut chiu di ca launch truss.

- Mt di ca cc mng trt cng c bi trn bng m.

+Chun b phng tin ko: Chun b cp ko, cu, Puli gim lc (Dng h Puli gim lc

6 cp), mt bng, h th v nhn lc

+Cc loi tu ko: H thng tu ko c chun b gm 1 tu ko SAO MAI 2.

+Tu dch v.

III.5.1.3.Chun b v iu kin thi tit.

Trc khi h thy KC th vic chun b v iu kin thi tit v iu kin v kh

tng hi vn l khu quan trng nht, n trnh c cc ri ro trong qu trnh thi cng

do thi tit mang li. Yu cu v iu kin thi tit v iu kin v kh tng hi vn

phc v cho qu trnh h thy nh sau: (Ngi thit k tnh ton da vo iu kin lm

vic ca cc phng tin h thy v thi tit ti cng).

- Tc gi cho php l 10(km).

- Nhit mi trng khong 20-30 C.

- Mc nc thy triu dao ng khong +_ 0.3 (m).

III.5.2.Thi cng h thy KC xung s lan.

III.5.2.1. Cng tc chun b.

Tin hnh vch sn v tr lp t KC trn s lan sao cho trng tm KC v trng tm

ca s lan cng nm trn mt ng thng theo phng thng ng. Sauk hi hon tt

ng tc chun b th tin hnh h thy KC.

III.5.2.2.Quy trnh h thy.

Chn thi im thi cng l thi im triu ln.

Trong n ny ta dung phng php h thy bng ko trt gm cc giai on nh

sau:

- a s lan vo v tr h thy v neo c nh vi u cng.

- Lp t h thng ko trt bao gm ti ko, h Puli gim lc, cp trn bi lp rp

v s lan.

- Bm nc dn vo s lan c mn nc h thy.

- H thy khi chn chia lm hai giai on ko trt KC trn cu cng bng

cu v ko trt KC trn s lan bng ti.

- Trong qu trnh ko trt lun gi cho mt boong s lan v mt cng bng nhau

bng vic bm nc dn vo hoc ra khoang ca s lan.

- Sau khi ko KC ln s ln n v tr vch sn th dng li, c nh KC vo mt

boong.

- Ko h s lan v KC ra v tr thun li khng lm nh hng ti giao thng

trong cng ch thi im vn chuyn ra v tr xy dng.

III.6.Quy trnh thi cng vn chuyn, nh chm.

III.6.1.Vn chuyn h s lan KC n v tr xy dng cng trnh.

III.6.1.1.Chun b cc phng tin vn chuyn v iu kin thi tit.

Sau khi hon tt qu trnh h thy KC, kim tra li lin kt gia s lan v KC,

chun b y cc tu ko v cc tu dch v, chun b h thng dy cp, h thng

thng tin lin lc gia cc tu ko, tu dch v v cc phng tin khc.

Chun b v iu kin thi tit v iu kin kh tng hi vn cho qu trnh vn chuyn

KC n v tr xy dng cng trnh.

Thu thp cac thng tin v thi tit, sao cho trong qu trnh vn chuyn v thi cng trn

bin iu kin thi tit lun m bo sao cho: (S liu c tnh ton theo yu cu ca

bn ch u t).

- Chiu cao sng ng k, Hs

Sau khi chun b xong cc phng tin v iu kin thi tit phc v cho qu trnh

vn chuyn KC th tin hnh vn chuyn KC ra v tr xy dng cng trnh nh sau:

- Tin hnh a tu ko Sao Mai 02 vo v tr, b tr tu ko Sao Mai 02 ko v tr

dc tu thng qua h thng cc dy cp.

- Tu ko Sao Mai 02 ko s lan v pha trc mt on khong 20m th tin hnh

chuyn hng ti ch bng cch quay mi tu v pha cn di chuyn vi s h tr

ca tu Vng Tu 01 pha ui s lan, sau khi a s lan ra cch mp cng mt

on khong 150m th gii phng tu Vng Tu 01 v vic ko s lan t cng ra

n v tr xy dng cng trnh c thc hin bi tu ko Sao Mai 02 cn tu ko

Vng Tu 01 i song song v cch tu ko Sao Mai 02 mt on khong 150-

200m (khong cch an ton m bo hai tu khng gy nh hng ln nhau),

h tr cho tu ko Sao Mai 02 khi cn thit ng thi tu ko Vng Tu 01 lm

lun cng tc ca tu dch v, tu ko Sao Mai 02 c lin kt vi s lan bng h

thng dy cp, c lin kt vi ma n. Trong qu trnh di chuyn trn bin cc tu

ko v tu dch v c lin lc thng xuyn vi nhau bng h thng b m,

ng thi trong qu trnh vn chuyn KC n v tr xy dng cng trnh phi tin

hnh theo di thng xuyn din bin cu thi tit, khi gp s c v thi tit xu

th phi so phng n x l ngay lp tc, nu trng hp gp thi tit xu khng

cho php tip tc vn chuyn KC th tin hnh di chuyn cc i tu v h KC

s lan tm ni n tr, nu nh gp bo v thi tit xu din ra t ngt th tin hnh

tho lin kt gia s lan v KC, a KC xung bin v nh du v tr th

KC, ri cho i tu di chuyn v v tr tr n, ch khi thi tit tt loi tip tc ra

trc vt KC ln v tin hnh vn chuyn tip KC ra v tr xy dng.

III.6.2.nh chm KC

i vi phng n ny, ui s lan c lp mt loi bn xoay chuyn dng vi mc

ch khi trng tm ca KC nm ra ngoi trng tm ca bn xoay th bn xoay s xoay

mt gc nh v y KC t t trt xung bin.

Nh s h tr ca lc y ni tc dng ln phn KC ngp nc lm cho s lan khng

b nghing mt gc qu ln v vn m bo v tr n nh.

Qu trnh nh chm gm cc giai on sau:

Giai on 1:

- nh v s b v tr xy dng cn trnh, neo s lan ti v tr xy dng bng h

thng neo thng qua cc tu ko.

- B tr h thng ko trt trn s lan.

- Dn sch ng trt, gii phng khi lin kt cng gia KC v mt boong.

Giai on 2:

- Dn nc vo pha ui s lan to mt nghing cho KC trt xung.

- Khi to c mt nghing nh thit k th dng bm nc dn.

- Cho KC trt v pha bn xoay c s h tr ca ti ko.

Giai on 3:

Trng tm ca KC vt ra khi tm bn xoay, lc ny KC xoay trn bn xoay, t

trt xung bin nh trng lng bn thn.

Giai on 4:

- Khi chn trt hon ton khi bn xoay, do lc y ni ln phn trn KC

ln v trng tm KC li gn pha di, KC t ng xoay v v tr cn bng.

- Sau khi khi chn xay v v tr cn bng, lc ny KC c th t ni, ko

KC n v tr xy dng v tin hnh c nh KC.

III.7.Quy trnh thi cng ng cc.

III.7.1.Nguyn tc ng cc.

Vic thi cng ng cc ph thuc rt nhiu vo iu kin kh hu khi thi cng thc t:

a cht cng trnh, mt bng thi cng, nghing lch ca chn . V nguyn tc khi

ng cc cn phi m bo sao cho chn t c cn bng tt nht. Cc cc s

c ng ng thi c 4 chn, tuy nhin ng n mc no hay dng ng cn cn c

vo thc t, l quyt nh ca ngi ch huy thi cng.

III.7.2.Thi cng ng cc v c nh KC.

III.7.2.1.Cng tc chun b cho qu trnh ng cc.

Chiu di ca on cc 12m, vi chiu dy nm trong kh nng nng nhc ca tu cu

Hong Sa.

Trong qu trnh ng cc m bo cc c ng xung chiu su thit k th cn

phi tin hnh nh du bng sn trng theo chiu di ca on cc thnh tng on

0.5m.

a tu cu Hong Sa vo v tr thc hin cng tc ng cc.Tu cu c da vo

v tr cch im xa nht ca KC mt on l 35m (ph hp vi tm vi ca cu). Chun

v v mc cu, s dng mc cu 300T ca tu cu Hong Sa, chun b cc loi cp phc

v cho cng tc cu ng cc.

Tin hnh hn v kim tra cc chi tit ti mc cu cc on cc v cc chi tit mc

cp cc on cc.

Chun b thit b u cc, thit b ny s c dung u cc khi tin hnh hn

ni cc on cc vi nhau.

Chun b ba ng cc v cc thit b khc phc v cho qu trnh ng cc, y ta s

dng ba ng cc l ba thy lc S-750.

Sau khi cng tc chun b cho vic ng cc c hon thin chu o th tin hnh

ng cc.

III.7.2.2.Quy trnh thc hin

- S dng cu Hong Sa cu cc on cc c chiu di 12m lng vo trong ng

chnh ca KC.

- i vi cc on cc u tin, sau khi lng cc vo ng chnh u cc nh ln

khi ng chnh 1 on l 1m, sau s dng thit b kp u cc c nh on

cc. Cu tip cc on cc tip theo hn vo on cc c lng vo trc ,

tho thit b kp cho cc t i xung. Tin hnh tng t cho n khi cc khng t

i xung na.

- Lp ba ng cc vo u cc v ng vo nn t cho n khi u cc nh ln

khi u ng chnh 1 on l 2-2,5m. Tin hnh ct u cc 1 on t 1-1,5 m (do

nh hng ca ba ng lm hng u cc). Sau cu lp cc on cc tip theo

v lm tng t cho n khi n cao trnh thit k ng cc.

- Thi gian ngng ng cc ti a cho php l 21h.

III.7.2.3.Bin php x l s c ng cc c th xy ra.

Trong qu trnh thit k thi cng KC ngoi bin ni chung v thi cng ng cc ni

ring th thng gp rt nhiu s c xy ra do thi tit bin khc nghit, tht thng, do

nhng tht thng trong khi thi cng kh c th lng trc c. Trong qu trnh thi

cng ng cc thng xy ra rt nhiu s c, nhng in hnh nht vn l cc s c di

y:

-S c gy ngang cc khi ng

Nguyn nhn:

- Trong qu trnh ng cc v cc qu di, ba ng li t u cc dn n n

nh ca thanh nh cng vi lc nn ln lm xut hin un ti cc v tr nguy

him, ti ng sut ln hn ng sut cho php ca cc.

Bin php khc phc:

- B on cc b gy thay on cc khc. Sau khi thay on cc khc th tin

hnh ng cc vi lc tc dng nh hn v chiu cao treo ba cng thp hn, khi

ng cc cc khc cng phi gia ti mt cch t t cho ba ng bng cch tang

dn s ln nh ba trong mt thi gian.

-S c u cc b ph hy khi ng.

Nguyn nhn:

- Do lc tc dng vo ba ln, do cng ca nn t ln dn n chi ca cc

ln.

- Sc chu ti ca u cc cha m bo.

Bin php khc phc:

- Ct b phn ph hy ca u cc, ng tip nhng phi ng vi lc nh hn, gia

ti mt cch t t.

-S c b tt.

Nguyn nhn:

- Do tnh ton sai t m xuyn hoc kt cu chn cc c hn khng tt, trong

qu trnh ng cc gp phi nn t qu yu, h s ma st nh khi lc ng ba

ln cc b tt hng xung pha di.

Bin php khc phc: V ng knh ca cc ln nn ta c th cho th hn chui vo ng

hn c on cc l vi nhau v tip tc ng.

-S c cc ng xung chiu su thit k m chi vn khng m bo.

Nguyn nhn: do khi kho st nn t cha k dn n cc gp phi lp t yu.

Bin php khc phc: Lp thp on cc ng tip.

-S c cc cha ng ht th b chi.

Nguyn nhn: xy ra khi cc gp phi tng t tt hoc tng cng.

Bin php khc phc: Thay ba c cng sut ln hn ri ng tip, nu vn khng c

th lp bo co gi v t lin tnh ton kim tra li. Nu sau khi tnh ton thy sau cc

m bo th dng li, cn khng m bo th c th dung phng php xi t ri tip

tc ng tip.

Ngoi cc s c k trn cn nhiu s c na nh cc m thng ng chnh, hng tm dn

hng

III.7.2.4.Chnh mt bng sau khi ng cc.

Thc t cho thy kho ng cc xong chn s khng cn thng ng nh trong bn

v thit k, c nhiu l do khc nhau dn n hin tng ny, nhng l do ch yu vn l

y bin khng bng phng v do qu trnh ng cc cng to nn nghing cc b

gia cc chn ca chn . khc phc hin tng ny ngi ta phi tin hnh cn

chnh li mt bng ca chn a chn v ng cao chun nh thit k. C

nhiu cch x l nhng ch yu dung 2 cch sau:

- Phng php dung kch thy lc 200T: Kch c cu to nh h pittong-xilanh,

dung my nn kh kch chn ln. Kch c b tr sao cho mt u th gn

vo cc cn u kia th gn vo chan sau khi cc lin kt m bo th

tin hnh kch chn ln. Thc t cho thy rng cch ny ch ko chn ln

c t 5-10mm. Mt khc phng php kch thy lc nh gn, v vic cn chnh

c kim sot lc rt d, rt tin li cho qu trnh thi cng trn bin v c can

ton rt cao, nn nu nh vic cn chnh mt bng khng b lch qu nn chn

phng php ny thi cng s dng.

- Phng php dung cu ni: y l phng php kh ph bin n c dung cho

nhiu cng trnh v thi cng d dng trong khi n c th ko chn ln n t

150-250mm. Dng mc cu 300T ca tu cu Trng Sa mc vo tai mc cp

(ca ng chnh cn ko) c sn chn ko ng ln cao cn thit th

dng li, c th dung thc hoc my kinh v xc nh cn ko ng ln bao

nhiu v cn chnh theo mt mt phng i qua bn tm ca 4 ng chnh t xc

nh c cao cn thit ca cc ng cn chnh cho chnh xc theo ng bn

v thit k. Tuy rng phng php ny c th ko c chn ln rt cao nhng

vn v lc ko th kh kim sot v vy an ton khi s dng phng php

ny l thp, nu lch nh th khng nn s dng phng php ny