ECC Final Binh Luan Ve Thiet Ke CKN DK 2m

7/25/2019 ECC Final Binh Luan Ve Thiet Ke CKN DK 2m

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D N U TXY DNG NT GIAO THNG KHC MC

TI NT GIAO THNG NG BA HU - TP. NNG

BO CO BNH LUN

TNH TON CHIU DI

CC KHOAN D2000 NHI TR THP

CNG TY C PH N T V N V U T X Y DNG ECCBK ENGINEERING AND CONSTRUCTION COMPANYa ch: 257 Nguyn Vn Linh TP NngTEL: 0511.3656388 FAX: 0511.3656691Email: [email protected] Website: www.bk-ecc.com.vn

Nng, Thng 3 Nm 2014


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D N U TXY DNG NT GIAO THNG KHC MC

TI NT GIAO THNG NG BA HU - TP. NNG

BO CO BNH LUN

TNH TON CHIU DI

CC KHOAN D2000 NHI TR THP

Thc hin: KS Phm Hng Nhn K s thng trKS Nguyn Trung Sn- TP K thutKS Nguy n Trn Thnh Nhn K s kt cu

CNG TY C PHN T VN V U T XY DNG ECC

Nng, Thng 3 Nm 2014


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I. Tng quan:...................................................................................................................... 4

II. M t a cht: ............................................................................................................ 4

III. M t thit k v bin php x l ca t vn thit k: .................................................. 7

IV. kin ca t vn gim st: ......................................................................................... 9

1. V ti trng tc dng ln cc: ....................................................................................... 10

2. V tnh ton sc chu ti: .............................................................................................. 10

3. Kt qu tnh ton i chng: ........................................................................................ 10

V. Kt lun: ................................................................................................................... 13

VI. Cc ph lc tnh ton

1. Tnh sc sc chu ti cc

2. Phn tch ti trng u cc bng phn mm RM v.8


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Cng trnh xy dng nt giao thng khc mc Ng Ba Hu. Thnh ph Nng l

cng trnh nt giao thng lp th nhiu tng. Tng mt t vi cc h thng ng

gom, tng 1 l vng xuyn vi cc nhnh r, t ng 2 l cu vt vi kt cu chnh gm

cc nhp dm BTCT bn rng v nhp cu dy vng mt thp i xng.

Theo thit k, nhp cu dy vng c khu 2x90m, kt cu dm ch pi. Tr thp

dng vm, mng c t trn 22 cc khoan nhi ng knh 2m. Trong kh un kh

bo co ny s bnh lun v chiu di cc D2000 ti tr thp T6 cu dy vng.

Cn c vo kt qu kho st hin trng, kt qu th nghim trong phng v bo co

a cht cu vt tng 2, a tng khu vc l khoan T6 t trn xu ng di bao gm cc

lp nh sau:

a/ Lp : t p : Kt cu mng, mt ng nha b tng xi mng, t p.

b/ Lp 3b: t ct ln bi (SM) xen kp cc lp st mng, mu xm xanh, xm trng,

trng thi bo ho, kt cu rt ri rccht va.

c/ Lp 4a: t st do (CH) ln dm sn, mu xm xanh, trng thi do chy.

d/ Lp 4b: Cp phi t tt (SW), mu xm xanh, trng thi bo ha, kt cu cht va.

e/ Lp 4f: t st t do (CL) mu xm trng, xm xanh. Trng thi cng.

f/ Lp 6a : phin phong ha nng, nt n, v vn, v dm, cng cp 4-6. TCR

thay i t 0% - 83.33%, RQD thay i t 046.66%.

g/ Lp 6b : phin phong ha nh, nt n, v tng, cng cp 7-8. TCR thay i

t 0% -92.3%, RQD thay i t 0%90.0%.


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Hnh 1: Mt ct a chttr thp T6


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Hnh 2: Hnh tr l khoan a cht LKT6-1

Hnh 3: Hnh tr l khoan a cht LKT6-2


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Hnh 4: Gii php ca T vn Thit k

Ngy 15-2-2014 T vn thit k trnh H s thit k cc khoan nhi tr T5, T6,

T7, trong i vi tr thp T6:

ng knh cc khoan l D = 2m, s lng cc: 22 cc ;

Cao mi cc ti l khoan T6 -1 l -50.60m tng ng vi chiu di cc l

49m, chiu su ngm trong lp 6b l 9.55m Cao mi cc ti l khoan T6-2 l -58.60m tng ng vi chiu di cc l

57m, chiu su ngm trong lp 6b l 18. 38m.

Ni lc u cc dng tnh ton l: 14055kN

Ngy 20-2-2014, ti vn phng Cty TNHH BT Ng Ba Hu Trung Nam, sau khi xem

xt hin trng, v i chiu h s thit k cc khoan nhi tr thp, i din T vn

Thit k ng Bi Hu Hng (Ch nhim n) thng nht:

Gim chiu di cc khoan nhi ti l khoan T6 -1 xung L=47,5m, t cao -

50.6m ln -49.1m; chiu su ngm trong lp 6b l 8.05m

Gim chiu di cc khoan nhi ti l khoan T6 -2 L=50,5m, t cao -58.6m

ln -52.1m; chiu su ngm trong lp 6b l 11.88m.

Ni lc u cc dng tnh ton l: 14055kN


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Ngy 11-3-2014 ti S giao thng vn ti Thnh Ph Nng , T vn Thit k

trnh by bng tnh vi cc ni dung chnh:

Gim chiu di cc khoan nhi ti l khoan T6 -1 v T6-2 xung L=45m, tngthm s lng cc.

T6-1 t cao -49.1m xung -46.6m; chiu su ngm trong lp 6b l 5.55m

T6-2 t cao -52.1m xung -46.6m; chiu su ngm trong lp 6b l 6.38m.

Ni lc u cc dng tnh ton l: 16439kNCung cp qua email.

Loi my khoan c s dng Bauer - BG36 l my khoan cc nhi c cng sut ln

nht hin c trn th trng Vit Nam .

Bng tng hp nht k khoan cc ti hin trng:

Tn

ccLpt

Cao (m)

Chi usu

khoan(m)

Thi giankhoan

Bt u khoan Kt thckhoanThi gian

(gi)

C11-

T6-1

6a -13.716a -40.71 27 8h28p (2-3-2014) 1h45p (8-3-2014) 138

6b -44.6 3.89 1h45p (8-3-2014) 0h08p (9-3-2014) 23C12-T6-2

6a -12.626a -39.32 26.7 10h00' (25-2-2014) 22h45' (27-2-2014) 736b -46.6 7.28 22h45' (27-2-2014) 23h30' (3-3-2014) 121

C15-T6-2

6a -12.676a -39.47 26.8 9h00' (6-3-2014) 19h45' (8-3-2014) 716b -46.67 7.2 19h45' (8-3-2014) 17h45' (10-3-2014) 46

C21-T6-2

6a -12.896a -39.61 26.72 20h00' (27-1-2014) 14h10' (16-2-2014) 4746b -52.1 12.49 14h10' (16-2-2014) 19h00' (21-2-2014) 125


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5.1. Cc tn ti trong Bng tnh thit k ca T vn Thit k

Hin nay TVGS cha nhn c bn tnh kt cu cu dy vng nn cha c c s xem

xt bnh lun v ti trng u cc. Tuy nhin vic thay i ti trng u cc t

14055kN ln n 16439kN qua hai ln cung cp s liu cho thy cng tc tnh ton

cha c hon thin vi tin cy cao.

Do cha c H s Thit k c th nn TVGS cha c c s tnh ton i chng ti

trng trn u cc ny. Tuy nhin qua tnh ton s b v so snh vi mt s d n

khc, TVGS cho rng ti trng u cc nh TVTK a ra l qu ln (bng tnh thamkho do ECC thc hin c ng trong Ph lc ca Bo co n y). S liu ny cn

c T vn Thit k v T vn Thm tra khng nh vi cc ti liu chi tit km

theo.

Vi l do mi khoan ti tr thp T6 -2 ti lp 6b ( su t 44.4m m 54,0m)

c nh gi RQD=0 do mu gy v khng ly c khi kho st a cht , TVTK

p cch tnh ton cho t ct cho ton h mng tr thp v p h s nhm ccn=0,65 l khng hp l, khng ng quy nh hin hnh, gy lng ph. Yu cu T

vn Thit k lm r vic p dng h s ny .

5.2. Kt qu quan st hin trng v tnh ton i chng ca TVGS ECC:

Vi thc t cc thit k ngm hn 27m phong ha nng cng cp 4~6 v hn

2m trong tng phong ha nh cng cp 7~8, theo iu 10.8.3.9 (22TCN272-05)

th vic p dng h s nhm cc 0,65 trong trng hp ny l khng ph hp, khng

ng vi Quy trnh hin hnh.

H s n cho nhm cc l nhm lm gim sc chu ti tnh ton ca mt cc trongnhm so vi sc chu ti ca mt cc n l. Vi cc n l th ton b vng tquanh cc c huy ng chng cho cc. Trong khi , trong nhm cc thcng t quanh cc phi chia s cho tt c cc cc dn n mi cc khng c tchng nhiu nh khi ch c cc n l. V vy, khi mt cc cng dy ln th cih s n ny cng nh i. Khi cc cc xa nhau nh m t cc n th ng nhin cih s n ny s phi bng 1. iu ny ch ng vi cc cc ma st.


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Vi cc cc chng, nh hng gia cc cc l khng ng k, c bit l khi cc chng vo tng cng th tt c cc cc s c sc chu ti nh cc n ngha l h snhm cc s phi bng 1. iu ny th hin r trong tiu chun TCXD 205-98 ti

iu 3.9.5 nh sau: "3.9.5. i vi coc chng, sc chu ti ca nhm cc bng tngsc chu ti ca cc cc n trong nhm"Nh vy, vic thit k ly h s n = 0,65 l lm sai vi quy nh ca tiu chun , dnn lng phv gy kh khn cho thc hin D n. S sai khc gia n =0,65 v n=1,00lm tng chi ph u t ln thm 54%.

Kt qu khoan a cht b sung ti tr thp t ngy 15 thng 3 nm 2014 cho thy

cht lng gc rt tt v ly c mu nguyn dng ca , hon ton khp vi

thc t theo di cng ca nn khi thi cng khoan cc cc trong khu vc tr thp.

Khoan a cht b sung ti tr thp Mu lp 6b ly c khi thi cng khoan

Mu khoan ly c su ~36m (Thuc lp 6a) Hin ang tip tc khoan


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Phng php v cng thc p dng: Vn dng cc cng thc trong 22 TCN 272-05

Vtr

Phng php tnh

Cng thc tnhTrch dn

theo 272-05Ghi chSc khng

bn

Sckhngmi

LKT6-1

Phngphp anpha qs = a Su

Theo iu 10.8.3.3.1 i vi t dnh

Quios &Resse qs = 0.0025N < 0.19Mpa

Theo bng 10.8.3.4.2-1 i vi t ri


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Cc ngm trong

N u qu 1.9Mpa thqs=0.15qu (Mpa) Theo iu C10.8.3.5

Cho trng hptng ln1.9Mpa thqs=0.21qu

0.5 (Mpa)

LKT6-2

Phngphp anpha qs = a Su

Theo iu 10.8.3.3.1 i vi t dnh

Quios &Resse qs = 0.0025N < 0.19Mpa

Theo bng 10.8.3.4.2-1 i vi t ri

Resse&O'Nill

qp = 0.057N for N 75Theo bng 10.8.3.4.3-1 i vi t ri

qp = 4.3 for N > 75

p dng tt ccphng php tnh theo quy trnh 22TCN 272-05 c trnh by trn ,

TVGS c kt qu nh sau (Dng cng nn ca 20,8 Mpa):T6-1

H mi L cc 6b SCT nKt qu (Chiu di cc 42m) -43.6 42 2.55 27454 1.67

T6-2

H mi L cc 6b SCT nKt qu (Chiu di cc 42m) -43.6 42 3.38 24932 1.52

6.1 Vic tnh ton d bo sc chu ti cc trong l vn cn nhiu kinh nghimv nh gi hin trng ca chuyn gia a k thut p dng cng thc hp l.Tuy nhin iu quan trng nht l kt qu tnh ton l thuyt phi c khng nhbng th nghim th ti theo quy nh trong iu 10.8.3.6 ca 22TCN 272-05.

6.2 Vi cc ngm su trong v chng v o cng c cng cp 7-8 (Lp 6b),

khng th p dng h s nhm cc 0,65(Vn p dng cho t dnh, cc ma st) m

phi p dng h s 1. Vi vic p dng h s ny th d tnh theo cch no, vi

chiu di cc xut L=42m cng u m bo yu cu vi h s an ton rt cao .

6.3 Hin nay a cht thc t cho thy khc vi s liu kho st ban u, theo

quy nh phi tnh ton li SCT ca cc . m bo chng lng ph, m bo

tin thi cng, T vn Gim st ECC kin ngh dng khoan tt c cc cc cn l i

su ti a 42m ( m bo iu kin ngm theo quy nh trong iu 6.2.2

ca TCVN 205-98) v s dng th nghim th ti cc theo quy nh trong mc


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10.8.3.6 trong 22 TCN 272-05 khng nh sc chu ti v chiu di cc tnh

ton.

6.4 Mt trong cc quy nh ca tt c cc Tiu chun v Quy chun l sc chu ti

ca cc n phi c khng nh bng th nghim th ti . V vy kin ngh thc

hin th ti xc nh chnh xc sc chu ti thc t ca cc ri t s iu chnh

thit k nu c sai khc ng k gia kt qu th nghim v kt qu tnh ton d bo .

Vi v tr kh khn v a hnh v cn ti trng th ln, TVGS kin ngh p dng

phng php th ti bng Osterberg Cell (O-Cell load test).


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Cc u im ca O-Cell test so vi th ti bng nn tnh

1.Khng cn hoc cn t i trng, ph hp ni b gii hn v khng gian

2.Cho c sc chu ti thnh v sc chu ti mi, cng vi chuyn v mi cc

3.C th dng vi ti trng th ln (200 n 300%)

Hin nay cc n v trong nc lm ch c vic thc hin th nghim O-cell nn

gi thnh th nghim khng t hn so vi phng php nn tnh truyn thng .

ECC Final Binh Luan Ve Thiet Ke CKN DK 2m

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