Tcxdvn 315-2004 Cttđ Sơn La Yêu Cầu Về Ổn Định Và Tk Ct Tạm

B xy dng cng ho x hi ch ngha vit nam S 07 /2004/ Q-BXD c lp - T do - Hnh phc H Ni , ngy 29 thng 4 nm 2004

Quyt nh ca B tr|ng b xy dng

V vic ban hnh Tiu chun xy dng Vit Nam TCXD VN 315 : 2004 " Cng trnh thu in Sn La - Cc quy nh ch yu v an ton v n nh

cng trnh - Tiu chun thit k cng trnh tm : quy v knh dn dng thi cng "

B tr|ng b xy dng

- Cn c Ngh nh s 36/ 2003/ N - CP ngy 04 / 4/ 2003 ca Chnh Ph quy nh chc nng, nhim v, quyn hn v c cu t chc ca B Xy dng.

- Cn c kin ngh ca cc chuyn gia nhn xt, phn bin tiu chun " Cng trnh thu in Sn La - Cc quy nh ch yu v an ton v n nh cng trnh - Tiu chun thit k cng trnh tm : quy v knh dn dng thi cng ".

- Xt ngh ca Tng Cng ty in lc Vit Nam ti vn bn s 1659/TTr - EVN-T ngy 14/4/2004 v V tr|ng V Khoa hc Cng ngh .

Quyt nh

iu 1 : Ban hnh km theo quyt nh ny 01 Tiu chun Xy dng Vit Nam TCXD VN 315: 2004 " Cng trnh thu in Sn La - Cc quy nh ch yu v an ton v n nh cng trnh - Tiu chun thit k cng trnh tm : quy v knh dn dng thi cng ".

iu 2 : Quyt nh ny c hiu lc sau 15 ngy k t ngy ng cng bo .

iu 3 : Cc ng : Chnh Vn phng B, V tr|ng V Khoa hc Cng ngh, Tng gim c Tng Cng ty in lc Vit Nam v Th tr|ng cc n v c lin quan chu trch nhim thi hnh Quyt nh ny ./. Ni nhn : b tr|ng b xy dng - Nh| iu 3 - VP Chnh Ph - Cng bo - B T| php - V Php ch - BXD - L|u VP&V KHCN k Nguyn Hng Qun

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www.vncold.vn Trang web Hi p ln Vit Nam

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Mc lc

Li ni u

1. Phm vi p dng

2. Tiu chun vin dn 3. Cc qui nh ch yu v an ton n nh cng trnh

3.1. Cc nguyn tc qui nh chung 3.2. Tnh ton n nh v bn theo tiu chun Vit Nam v Lin X c 3.3 Tnh ton n nh v bn theo cc h|ng dn ca M 4. Tiu chun thit k cng trnh tm - quy v knh dn dng

4.1 Cp cc cng trnh tm 4.2 Xc nh tn sut, l|u l|ng thit k cng trnh tm 4.3 Tn sut gi 4.4 Tiu chun v ti trng v tc ng 4.5 Cc qui nh tnh ton ch yu 4.6 Ph lc cc tiu chun s dng cho cng trnh tm.

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li ni u

TCXDVN 315 : 2004 Cng trnh thu in Sn La, cc qui nh ch yu v an ton v n nh cng trnh, tiu chun thit k cng trnh tm - quy v knh dn dng thi cng do Cng ty T| vn xy dng in 1 Tng Cng ty in lc Vit Nam bin son, V Khoa hc cng ngh B Xy dng ngh v |c B Xy dng ban hnh theo quyt nh s 07 2004/Q-BXD ngy 29 thng 4 nm 2004.

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1. Phm vi p dng

Tiu chun ny qui nh cc yu cu chung v an ton n nh cng trnh chnh v tiu chun thit k cng trnh tm - quy v knh dn dng thi cng ca thu in Sn La.

2. Tiu chun vin dn

- Quy chun xy dng Vit Nam

- TCXDVN 285:2002

- TCXDVN 250 : 2001

3. Cc quy nh ch yu v an ton v n nh cng trnh D n Thu in Sn La l D n c qui m ln, thuc cp c bit, l cng

trnh quan trng ca Quc gia, |c Th t|ng Chnh Ph ph duyt u t|. m bo an ton cho cng trnh, Tiu chun thit k v an ton n nh

cng trnh |c kin ngh, lp t cc tiu chun ca Vit Nam, Lin X c v ca M.

Cc tiu chun v an ton n nh cng trnh s bao gm : - Tiu chun an ton n nh cng trnh chnh, bao gm cc cng trnh lu di

(cng trnh ch yu v th yu). - Tiu chun thit k cng trnh tm - quy v knh dn dng

Trong tp Tiu chun ny nu cc nguyn tc qui nh chung lp tiu chun an ton n nh cng trnh chnh v Tiu chun thit k cng trnh tm - quy v knh dn dng. 3.1 Cc nguyn tc quy nh chung

3.1.1 Tiu chun ny bao gm cc qui nh ch yu v an ton n nh cng trnh cn phi p dng khi lp thit k, thm nh, xt duyt Thit k k thut D n thu in Sn La. 3.1.2 Tuyn chn Pa Vinh II b tr cng trnh |c Th t|ng Chnh Ph ph duyt u t| D n thu in Sn La ti vn bn s: 92/Q-TTg ngy15 thng 01nm 2004. Vic b tr cc cng trnh p dng, p trn x l v nh my thu in ch dng kt cu b tng v b tng ct thp. Ring tiu chun tnh ton v an ton, n nh cng trnh p t |c cp l cc cng trnh quy. 3.1.3. Cc tiu chun tnh ton v an ton, n nh ca cng trnh :

D n thu in Sn La l D n c bit quan trng i vi vic pht trin kinh t t n|c, ng thi cng l D n c qui m ln nht Vit Nam hin nay, theo Bo co NCKT |c ph duyt p c chiu cao ln hn 130m, nh my thu in c cng sut N=2400MW, h cha n|c c dung tch 9,26 t m3, h du c thu in Ho Bnh, th H Ni v ng bng bc b...nn an ton, n nh ca cc cc cng trnh chnh trn tuyn p lc (p dng, p trn, ca ly n|c) phi m bo mc an ton cao. i vi cng trnh thu in Sn La vi mc n|c dng bnh th|ng 215,00 m, mc n|c gia c|ng khi c l tn sut 0,01% l 218,45 m v khi c l PMF l 231,43 m. Chnh lch gia MNDBT v mc n|c khi c PMF

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qu cao do phi iu tit chng l cho thu in Ho Bnh, trong khi theo tiu chun Vit Nam v Lin X c khng c tr|ng hp tnh ton kim tra vi tr|ng hp l PMF. m bo an ton cng trnh v t |c cc tiu chun an ton theo cc tiu chun Quc t khc, tiu chun ny |a ra vic tnh ton n nh ca cc cng trnh trn tuyn p lc theo hai h thng tiu chun, h|ng dn sau: 1) Tnh ton n nh theo tiu chun ca Vit Nam v Lin X c, b sung t hp

lc khi c l PMF v kin ngh cc h s an ton n nh cho php (thc hin ng b vi cc ch tiu ca vt liu, ph|ng php tnh ton, h s n nh cho php)

2) Kim tra tnh ton n nh theo cc tiu chun, h|ng dn ca M(thc hin ng b vi cc ch tiu ca vt liu, ph|ng php tnh ton, h s n nh cho php)

H s an ton n nh |c kin ngh phi ng thi tho mn c hai h thng tiu chun, h|ng dn nu trn.

Cc hng mc cn li |c tnh ton theo tiu chun Vit Nam, tiu chun ngnh ca Vit Nam v tiu chun ca Lin X c, cng cc ti liu h|ng dn. 3.2. Tnh ton n nh v bn theo tiu chun ca Vit Nam v Lin X

c

Cc tiu chun tnh ton v an ton, n nh ca cng trnh |c tnh ton trn c s phn cp v phn loi cc hng mc cng trnh theo qui nh sau : 3.2.1. Phn loi cng trnh

Cc hng mc cng trnh thu in Sn La |c phn loi nh| sau: 3.2.1.1 Cng trnh lu di

Theo chc nng, tm quan trng v thi gian s dng, cng trnh trong d n |c chia thnh cng trnh ch yu v th yu. 1) Cng trnh ch yu

Cng trnh ch yu l cng trnh quan trng, nu chng b h| hng hoc b ph hu s lm cho nh my thu in khng th lm vic |c bnh th|ng, lm ngng tr vic cung cp n|c, gy ra ngp lt cc vng dn c|, th, kinh t... h du. Cc hng mc cng trnh gm :

a. p dng b. p trn x l c. p - Ca ly n|c, |ng dn n|c, x n|c, nh my thu in v trm

phn phi in ngoi tri. d. T|ng bin, t|ng chn e. Knh dn v cc cng trnh trn knh f. Cng trnh gia c b v chnh tr sng lin k vi cc cng trnh ch yu g. T|ng phn dng th|ng v h l|u

2) Cng trnh th yu

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Cng trnh th yu l nhng hng mc cng trnh m s h| hng ca chng khng nh h|ng n s lm vic bnh th|ng ca cng trnh u mi v h thng, c th phc hi trong mt thi gian ngn. Nhng hng mc bao gm :

a. T|ng bin v t|ng chn khng nm trong tuyn chu p b. Cc cng trnh gia c b nm ngoi cm cng trnh u mi c. Nh qun l hnh chnh.

3.2.1.2 Cng trnh tm thi

Cng trnh tm thi l nhng cng trnh phc v cho xy dng cng trnh chnh, ch s dng trong thi k xy dng hoc ch dng sa cha cng trnh lu di trong thi k khai thc. Cc hng mc cng trnh ny gm:

a. quy h mng b. Knh, cng v cng trnh dn, x l|u l|ng thi cng

3.2.2. Phn cp cng trnh

Cp cng trnh thu in Sn La |c xc nh trn c s ca TCXDVN 285 : 2002 v Tiu chun ca Lin X c CHu3 2.6.01.86. 3.2.2.1. Cp cc hng mc cng trnh ch yu

1) Cc hng mc cng trnh to tuyn p lc gm:

a. p khng trn b. p trn c. p - Ca ly n|c

|c xp vo cp c bit v p c chiu cao ln hn 130 m, nh my thu in c cng sut N=2400MW, h cha n|c c dung tch gn 9,26 t m3, h du c thu in Ho Bnh, th H Ni, nhiu thnh ph, trung tm kinh t, chnh tr, vn ho, u mi giao thng quan trng ca c n|c. 2). Cc hng mc cng trnh nm ngoi tuyn p lc

a. Nh my thu in: xp cp I b. Trm phn phi in ngoi tri: xp cp I

3.2.2.2. Cp cc cng trnh th yu.

Gm cc hng mc nu mc 3.2.1.1, |c xp cp II. Theo TCXDVN 285:2002 l cp III, do tm quan trng c bit ca thu in Sn La, tng mt cp so vi tiu chun. 3.2.3. Xc nh l thit k v kim tra

3.2.3.1. Cng trnh ch yu

Thit k vi tn sut l 0,01% (c gia tng 'Q theo qui phm) Kim tra vi l PMF

3.2.3.2. Cng trnh th yu ly theo theo TCXDVN 285:2002 v CHu3 2.6.01.86.

3.2.4. Tn sut gi

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Tn sut gi tnh trong thi k xy dng v vn hnh ly theo cp cng trnh v mc n|c t|ng ng ti tng thi im. Ly p=2% khi h cha mc n|c dng bnh th|ng v p=50% khi h cha mc n|c gia c|ng. 3.2.5 Tiu chun v ti trng v tc ng

3.2.5.1. Nguyn tc chung

Cc ti trng v tc ng cng trnh thu in Sn La |c xc nh theo cc tiu chun Vit Nam TCXDVN 285 : 2002, 14 TCN 56-88 v cc tiu chun ca Lin X c CHu3 2-06.01.86, CHu3 2-06.85, CHu3 II-7-81. 3.2.5.2. Cc ti trng v tc ng tnh ton

1). Cc ti trng th|ng xuyn v tm thi (Di hn v ngn hn)

a). Gm trng l|ng ca cng trnh v cc thit b c nh t trn v trong cng trnh

b). p lc n|c tc ng trc tip ln b mt cng trnh v nn c). Trng l|ng t, v p lc bn ca n

d). p lc t pht sinh do bin dng nn v kt cu cng trnh, do ti trng bn ngoi khc.

e). p lc bn ct. f). Tc dng ca co ngt v t bin g). Tc ng nhit ln cng trnh trong thi gian thi cng v khai thc ca

nm c bin giao ng nhit bnh qun thng ca khng kh l trung bnh. h). Ti trng do tu, thuyn v vt tri i). Ti trng do cc thit b nng, bc r, vn chuyn v cc my mc,

kt cu khc (cn trc, cu treo, pa lngvv...), cht lng c xt n kh nng cht v|t ti thit k.

j). p lc sng xc nh theo tc gi ln nht trung bnh nhiu nm.

k). p lc gi

l). p lc n|c va trong thi k khai thc. m). Ti trng ng sinh ra trong |ng dn c p v khng p khi dn n|c mc n|c dng bnh th|ng.

2). Cc ti trng tm thi c bit gm : a). Ti trng do ng t hoc n

b). p lc n|c thm gia tng khi thit b chng thm v tiu n|c khng lm vic bnh th|ng. c). Tc ng do nhit trong thi k thi cng v khai thc ca nm c bin dao ng nhit bnh qun thng ca khng kh ln nht.

d). p lc sng khi xy ra tc gi ln nht.

e). p lc n|c va khi t ngt ct ton b ph ti. f). Ti trng ng sinh ra trong |ng ng dn c p v khng p khi dn n|c mc n|c ln nht

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g). p lc pht sinh trong mi t do mc n|c sng, h b h thp t ngt (rt nhanh).

h). p lc n|c khng bnh th|ng ln cng trnh v nn (mc n|c gia c|ng vi l P = 0,01%, mc n|c vi l PMF).

3.2.5.3. T hp ti trng

Khi thit k cng trnh thu phi tnh ton theo t hp ti trng c bn v kim tra theo t hp ti trng c bit.

a). T hp ti trng c bn bao gm cc ti trng v tc ng: Th|ng xuyn, tm thi di hn, tm thi ngn hn m cc hng mc ang thit k c th phi tip nhn cng mt lc. b). T hp ti trng c bit vn bao gm cc ti trng v tc ng xt trong t hp ti trng c bn nh|ng mt trong chng |c thay th bng ti trng (hoc tc ng) tm thi c bit. Tr|ng hp ti trng c bn c xt thm ti trng ng t hoc n cng xp vo loi t hp c bit.

3.2.5.4. Cc tr s tnh ton

a). Trng l|ng bn thn cng trnh v cc ch tiu tnh ton ca vt liu ly theo ch tiu kin ngh c th cho tng loi vt liu.

b). p lc thu tnh ln cng trnh tnh theo dung trng n|c Jn=1T/m3

c). p lc ng|c(bao gm p lc thm v y ni), trong tnh ton ly ly h s D2=1.0 d). ng t tnh vi ng t thit k (DE), ng t tin cy ln nht (MCE) v theo CHu3 II-7-81.

3.2.6. Cc qui nh tnh ton ch yu

3.2.6.1. Khi tnh ton n nh, bn, ng sut, bin dng chung v cc b cho cc cng trnh thu v nn ca chng, phi tin hnh tnh ton theo ph|ng php trng thi gii hn. Cc tnh ton cn phi tin hnh theo hai nhm trng thi gii hn.

a). Trng thi gii hn th nht gm: cc tnh ton v bn v n nh chung ca h thng cng trnh-nn. b). Trng thi gii hn th hai gm: cc tnh ton bn cc b ca nn, tnh ton v hn ch chuyn v v bin dng, v s to thnh hoc m rng vt nt v mi ni thi cng.

3.2.6.2. iu kin an ton n nh ca cc cng trnh.

|c xc nh theo iu 6.2 ca TCXDVN 285 : 2002 v iu 2.2 ca CHu3 2.6.01.86 :

Trong :

nc h s t hp ti trng

RknmNttn c d.

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- Trong tnh ton theo trng thi gii hn th nht :

nc = 1,0 i vi t hp ti trng c bn; = 0,9 i vi t hp ti trng c bit = 0,95 i vi t hp ti trng trong thi k thi cng v sa cha

- Trong tnh ton theo trng thi gii hn th hai : nc=1

Ntt Ti trng tnh ton tng qut (lc, m men, ng sut), bin dng hoc thng s khc m n cn c nh gi trng thi gii hn.

R Sc chu ti tng qut,bin dng hoc thng s khc |c xc lp theo tiu chun thit k (TCVN, TCXD, TCXDVN, TCN,).

m h s iu kin lm vic: khi mt tr|t i qua mt tip xc gia b tng v hoc i trong nn c mt phn qua cc khe nt, mt phn qua nguyn khi ly m=0,95 cc tr|ng hp khc cn li ly m=1,0.

- Khi tnh ton theo trng thi gii hn th nht: kn |c xc nh theo cp cng trnh : Cp c bit kn >1,25 (s |c kin ngh sau) Cng trnh cp I ly kn =1,25 Cng trnh cp II ly kn =1,20 Cng trnh cp III, IV v V ly kn =1,15

- Khi tnh ton theo trng thi gii hn th hai: ly nc=1,0

3.2.6.3. H s n nh ca cng trnh tnh theo cng thc

K h s n nh ca cng trnh. 3.2.6.4. H s lch ti (n) khi tnh ton theo trng thi gii hn mt v hai ly theo TCXDVN 285: 2002 CHu3 2.06.01.86 v cc tiu chun ngnh

3.2.6.5. ng sut mt th|ng l|u p v mt tip gip gia p v nn

ng sut mt th|ng l|u p v mt tip gip gia p v nn s |c nghin cu ph hp vi tiu chun kin ngh. 3.3. Tnh ton n nh v bn theo cc h|ng dn ca M

3.3.1. Ti trng

1). Tnh ti Gm trng l|ng ca cng trnh v cc thit b c nh t trn v trong

cng trnh

2). p lc n|c tc dng ln th|ng, h l|u cng trnh

3). p lc ng|c

m

knnNttRK c .t

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7) Tr|ng hp 7- iu kin ti trng c bit l ln nht c th (extrem loading condition probable maximum flood. PMF). (a) H mc n|c khi c l ln nht c th (PMF)

(b) Tt c cc ca van u m, mc n|c h l|u t|ng ng khi x l PMF

(c) p lc ng|c

(d) p lc n|c h l|u

(e) p lc bn ct nu c

4. Tiu chun thit cng trnh tm - quy v knh dn dng 4.1. Cp cc cng trnh tm

Cng trnh thu in Sn La l cng trnh c bit quan trng nn mt s hng mc ca cng trnh tm |c tng mt cp so vi tiu chun Vit Nam. 1) quy h mng

- quy giai on I: Phc v thi cng knh dn dng trong thi gian ngn (mt ma kh) thuc cp IV.

- quy giai on II: xp cp III, do phi m bo an ton cho cng trnh trong h mng v h du, tng ln mt cp so vi TCVN.

- quai giai on III : xp cp III t|ng t giai on II 2) Cng dn dng qua thn p (Cc l x su thi cng)

Cc l x qua p nm trong cng trnh chnh |c ly theo cp cao nht ca cng trnh chnh trong thi gian dn dng qua cng. 3) Knh dn dng thi cng - Knh dn dng thi cng: xp cp III tng mt cp so vi TCVN. - Mi knh th|ng l|u: xp cp I v l mi vn hnh lu di. 4) quy dc (T|ng phn cch) gia knh v h mng giai on II: xp cp III,

tng mt cp so vi TCVN. Ghi ch: Tr|ng hp cng trnh chnh s dng mc ch tm thi trong thi

ban u th phi theo cp cng trnh lu di (Ch yu hoc th yu).

4.2. Xc nh tn sut, l|u l|ng thit k cng trnh tm

4.2.1. S x l|u l|ng thi cng chung

Thc hin qua 3 giai on : - Giai on I : X l|u l|ng thi cng qua lng sng t nhin, p quai dc

giai on I thi cng knh dn dng. - Giai on II : Lp sng, p quai giai on II, x l|u l|ng thi cng qua

knh thi cng. - Giai on III : Lp knh thi cng x l|u l|ng ma kit hoc c ma l, kit

qua cc l x (cng) tm thi phn p (hoc p xy d trn knh thi cng).

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Nt l x thi cng, l|u l|ng chuyn qua l x su cng trnh x vn hnh xy d. 4.2.2. Cc cng trnh tm

1) quy h mng - Giai on I dn dng qua lng sng t nhin, tn sut thit k cho quy l

p=10%, Ql = 12.713m3/s. - Giai on II dn dng qua knh thi cng, tn sut thit k cho quy l

p=5%, Ql = 14.642m3/s. - Giai on III , dn dng qua l x su hoc qua knh thi cng vi p xy

d, tn sut thit k, p=3%, Ql = 16.044m3/s. 2) Knh dn dng thi cng, tn sut thit k l p=5%, Ql = 14.462m3/s. 3) quy dc (T|ng phn cch), tn sut thit k l p=5%, Ql = 14.462m3/s. 4) Nu cc quy lm vic trong nhiu giai on th tn sut thit k ly theo

giai on cui cng. 4.3. Tn sut gi

Tn sut gi tnh trong thi k xy dng ly theo cp cng trnh v mc n|c t|ng ng ti tng thi im. i vi quy giai on II, III (cp III) ly tn sut gi 4%. 4.4. Tiu chun v ti trng v tc ng

4.4.1. Nguyn tc chung

Cc ti trng v tc ng cng trnh thu in Sn La |c xc nh theo cc tiu chun Vit Nam TCXDVN 285:2002, 14 TCN 56-88 v cc tiu chun ca Lin X c CHu3 2-06.01.86, CHu3 2-06.85, CHu3 II-7-81.

4.4.2. Cc ti trng v tc ng tnh ton

1). Cc ti trng th|ng xuyn v tm thi (Di hn v ngn hn)

a). Gm trng l|ng ca cng trnh v cc thit b c nh t trn v trong cng trnh

b). p lc n|c tc ng trc tip ln b mt cng trnh v nn, p lc thm ng vi mc n|c thit k trong iu kin thit b lc v tiu n|c lm vic bnh th|ng.

c). Trng l|ng t , bn ct v p lc bn ca n.

d). p lc t pht sinh do bin dng nn v kt cu cng trnh, do ti trng bn ngoi khc.

e). Ti trng gy ra do p lc d| ca k rng trong t bo ho n|c khi ch|a c kt hon ton mc n|c thit k, trong iu kin thit b lc v tiu n|c lm vic bnh th|ng.

f). Tc ng nhit ln cng trnh trong thi gian thi cng v khai thc ca nm c bin giao ng nhit bnh qun thng ca khng kh l trung bnh.

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g). Ti trng do cc thit b nng, bc r, vn chuyn v cc my mc, kt cu khc (cn trc, cu treo, pa lngvv...), cht lng c xt n kh nng cht v|t ti thit k.

h). p lc sng xc nh theo tc gi ln nht trung bnh nhiu nm.

i). p lc gi j). Ti trng ng sinh ra trong |ng dn c p v khng p khi dn mc n|c thit k. 2). Cc ti trng tm thi c bit gm :

a). Ti trng do ng t hoc n

b). p lc n|c thm gia tng khi thit b chng thm v tiu n|c khng lm vic bnh th|ng.

c). Ti trng gy ra do p lc d| ca k rng trong t bo ho n|c khi ch|a c kt hon ton mc n|c thit k, trong iu kin thit b lc v tiu n|c b hng.

d). Tc ng nhit ln cng trnh trong thi gian thi cng v khai thc ca nm c bin giao ng nhit bnh qun thng ca khng kh l ln nht.

e). p lc sng xy ra tc gi ln nht thit k.

f). p lc pht sinh trong mi t do mc n|c sng, h b h thp t ngt (rt nhanh).

4.4.3. T hp ti trng

Khi thit k cng trnh thu phi tnh ton theo t hp ti trng c bn v kim tra theo t hp ti trng c bit. a). T hp ti trng c bn bao gm cc ti trng v tc ng: Th|ng xuyn, tm thi di hn, tm thi ngn hn m cc hng mc ang thit k c th phi tip nhn cng mt lc. b). T hp ti trng c bit vn bao gm cc ti trng v tc ng xt trong t hp ti trng c bn nh|ng mt trong chng |c thay th bng ti trng (hoc tc ng) tm thi c bit. Tr|ng hp ti trng c bn c xt thm ti trng ng t hoc n cng xp vo loi t hp c bit. 4.4.4. Cc tr s tnh ton

a). Trng l|ng bn thn cng trnh v cc ch tiu tnh ton ca vt liu ly theo ch tiu kin ngh cho tng loi vt liu.

b). p lc thu tnh ln cng trnh tnh theo dung trng n|c, Jn=1T/m3

c). p lc ng|c (bao gm p lc thm v y ni), trong tnh ton ly ly h s D2=1,0 c). Cp v lc ng t

Theo iu 5.4 ca CHu3 II-7-81 xy dng trong vng ng t ca Lin X c nu: Khi thit k cc cng trnh chn n|c phi tnh ti kh nng tc ng ca ng t trong qu trnh xy dng. Cp ng t ca khu vc xy dng cng trnh chn n|c trong tr|ng hp ny gim i mt cp. Cng trnh thu in

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Sn La |c xy dng trong vng ng t cp 8 (thang MSK). Nh| vy cp ng t tnh ton cng trnh kin ngh nh| sau: - Mi knh thi cng th|ng l|u l mi vn hnh lu di, ng t tnh ton cp 8

(gia tc nn cc i ti tuyn cng trnh a=0,23 g) - Cc quy giai on II, III tnh ton vi ng t cp 7 (gia tc nn cc i

a=0,1 g).

x Ti trng ng t

Cng theo mc 2.5 ca CHu3 II-7-81, ti trng ng t xc nh theo cng thc: Sik=K1.K2.Soik (4-1)

Soik=Qk.A.Ei.KIKik (4-2)

Trong : K1 - h s hng hc cho php ca nh v cng trnh :

- K1=0,25: ly theo bng 4 ca qui phm trn - K1=0,5 kin ngh kim tra

A h s ly bng 0,1; 0,2; t|ng ng vi cp ng t tnh ton cp 7, cp 8 Vic tnh ton kim tra vi K1=0,5 theo tiu chun Nga l cn thit nng

mc an ton cho cng trnh v theo h|ng dn ca cc n|c Ph|ng Ty h s ng t s dng tnh ton n nh thay i t (0,5-0,7) gia tc nn cc i. Tuy nhin theo tiu chun tnh ton ny i hi h s an ton cho php ln hn tiu chun Nga.

H s an ton n nh xem bng 4-1 ca tiu chun ny. d). Cao trnh nh quy.

Cao trnh nh quy xc nh theo Qui trnh thit k dn dng, lp dng 14 TCN 57-88.

x quy giai on I

q =mn+ a (4-3) Trong :

q - Cao nh quy (m)

mn- Cao trnh mc n|c tnh ton (m) a - cao an ton tnh ca quy ly 0,7 m

x quy giai on II, III Do tr|c quy mt n|c c chiu di hng gi ng k nn cao trnh nh

quy xc nh theo cng thc:

q =mn+d (4-4)

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Trong :

mn- Cao trnh mc n|c tnh ton (m) d - v|t cao nh quy trn mc n|c tnh ton

V d=hs1%+'h+a Trong : hs1% - l chiu cao sng ng vi tn sut 1% tnh theo QP.TL-C-1-78 Qui phm ti trng v lc tc dng ln cng trnh thu li

'h - l dnh mc n|c th|ng l|u do gi. a - cao an ton tnh ca quy ly 0,7 m 4.5. Cc qui nh tnh ton ch yu

4.5.1. Khi tnh ton n nh, bn, ng sut, bin dng chung v cc b cho cc cng trnh v nn ca chng, phi tin hnh tnh ton theo ph|ng php trng thi gii hn. Cc tnh ton cn phi tin hnh theo hai nhm trng thi gii hn.

a). Trng thi gii hn th nht gm: cc tnh ton v bn v n nh chung ca h thng cng trnh-nn. b). Trng thi gii hn th hai gm: cc tnh ton bn cc b ca nn, tnh ton v hn ch chuyn v v bin dng, v s to thnh hoc m rng vt nt v mi ni thi cng.

4.5.2. iu kin an ton n nh ca cc cng trnh

|c xc nh theo iu 6.2 ca TCXDVN 285 : 2002 v iu 2.2 ca CHu3 2.6.01.86:

RknmNttn c d.

(4-5) Trong : nc h s t hp ti trng - Trong tnh ton theo trng thi gii hn th nht:

nc = 1,0 i vi t hp ti trng c bn; = 0,9 i vi t hp ti trng c bit = 0,95 i vi t hp ti trng trong thi k thi cng v sa cha

Ntt Ti trng tnh ton tng qut (lc, m men, ng sut), bin dng hoc thng s khc m n cn c nh gi trng thi gii hn.

R Sc chu ti tng qut, bin dng hoc thng s khc |c xc lp theo tiu chun thit k (TCVN, TCXD, TCXDVN, TCN,).

m h s iu kin lm vic: khi mt tr|t i qua mt tip xc gia b tng v hoc i trong nn c mt phn qua cc khe nt, mt phn qua nguyn khi ly m=0,95 cc tr|ng hp khc cn li ly m=1,0.

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- Khi tnh ton theo trng thi gii hn th nht: kn |c xc nh theo cp cng trnh :

Cng trnh cp I ly kn=1,25 Cng trnh cp II ly kn=1,20 Cng trnh cp III, IV kn=1,15

- Khi tnh ton theo trng thi gii hn th hai: ly nc=1,0 4.5.3. H s n nh ca cng trnh tnh theo cng thc

m

knnNttRK c .t

(4-6) K h s n nh ca cng trnh. H s n nh tnh cho cc tr|ng hp t hp ti trng v cp cng trnh ghi

trong bng 4-1 Bng 4-1 - Bng h s an ton n nh

H s n nh cho php K* Cp cng

trnh TH c bn TH c bit TH thi cng,

sa cha c bit

khi thi cng

I 1,25(1,32) 1,13(1,19) 1,19(1,25) 1,07(1,19)

II 1,20(1,26) 1,08(1,14) 1,14(1,20) 1,03(1,14)

III, IV 1,15(1,21) 1,04(1,09) 1,09(1,15) 1,00(1,09)

Ghi ch: * K=1,0 cho cc tr|ng hp khi tnh ton kim tra vi K1=0,5

Gi tr ghi trong du ngoc tnh m=0,95; cn li m=1,00 4.5.4. H s lch ti (n) khi tnh ton theo trng thi gii hn mt ly theo

TCXDVN 285: 2002 v cc tiu chun ngnh. 4.5.5. Tnh n nh cng trnh

1). Tnh n nh v bn cng trnh b tng ( quy b tng)

n nh chng tr|t, chng lt ca cng trnh |c kim tra theo iu 6.2 ca TCXDVN 285: 2002, iu 2.2 CHu3 2.06.01-86, iu 7.6 CHu3 2.06.06-85 v iu 3.15 y 3.20 CHu3 2.02.02-85

(a). n nh chng tr|t ca cng trnh trn nn . Khi tnh ton n nh theo s tr|t phng, h s n nh chng tr|t Ktr

|c xc nh theo cng thc:

Ktr=( PtgM+CA)/Tt [K] (4-7)

Trong :

P: tng cc lc thng ng

T: tng cc lc ngang gy tr|t.

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tgMC ch tiu tnh ton ca nn A : din tch tnh ton Ktr : H s n nh

(b). n nh lt. Tnh ton n nh v lt quanh im h l|u cng trnh theo cng thc:

Kl= ( Mr/Mt)t [K] (4-8) Trong :

Mr: tng m men cc lc chng lt

Mt : tng m men cc lc gy lt

(c). ng sut trong thn quy v mt tip gip gia quy v nn.

ng sut mt th|ng l|u v trong thn quy cng nh| ng sut mt tip gip gia quy v nn kim tra theo 14 TCN-56-88, CHu3 2.06.06-85, CHu3 2.02.02-85. 2). Tnh n nh mi dc quy t v mi dc o.

Tnh ton n nh mi dc theo ph|ng php phn thi, khi tr|t c hnh dng bt k |c chia thnh cc thi nh| hnh v.

Cc gi thit :

- bn ca t xc nh theo nh lut Coulomb.

'tan)u('c IV W

vi :

W : c|ng chng ct.

c, I : lc dnh, gc ma st trong

- H s an ton thuc thnh phn dnh v ma st l nh| nhau cho mi loi t:

> @F

uuu

Fc bwaan EIIVE tan'tan'

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- H s an ton F l nh| nhau cho cc thi ( n thi )

- Lc tc dng ln cc thi gm:

Trng l|ng bn thn : W Lc ng t : kW, t ti trng tm thi Ti trng tc dng trn nh thi D. Lc tc dng trn hai mt bn ca thi : EL, ER, XL,XR Lc tc dng ti y thi : Lc php tuyn N; Lc tip tuyn ti mt y thi -|c huy ng tho mn iu kin cn bng gii hn Sm.

> @F

tanuc

F

.sS

,

n

,

m

IVE

E

(4-9)

Lc tc dng ln cung tr|t: p lc n|c AR, AL.

Ph|ng trnh cn bng m men ca cc thi t quanh tm tr|t:

> @

Fc R N u R

Wx Nf kWe Dd Aam = ' + - '

- +

E E Itan r r

(4-10)

Ph|ng trnh cn bng lc ca tt c cc thi t theo ph|ng ngang :

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> @

Fc N u

N kW D Af =

' + - '

+ -

E D E I D

D Z

cos tan cos

sin cos

r

(4-11)

Lc tc dng theo ph|ng php tuyn ti y thi:

> @, ,

R L

,

c . sin u sin tanW X X Dsin

FNsin tan

cosF

E D E D I Z

D I

D

(4-12)

T (4-12) cho thy (4-10) v (4-11) c dng hm n cho nn khng gii trc tip |c, mt khc ch|a xc nh |c XR, XL.

n gin ha cc tc gi ngh cc gi thit. Fellenius, 1936 : b qua nh h|ng ca lc t|ng tc theo ph|ng ng v

ngang gia cc thi t. > @90cosDsinkWcosWN DZDD

(4-13) Biu thc tnh n nh theo ph|ng php Fellenius

> @ > @ > @ Aa Dd kWe + f90cosDsinkWcosW - Wx

' tan R u - 90cosDsinkWcosW + R'c = Fm rrDZDD

IEDZDDE

(4-14)

Gi thit chnh lch lc t|ng tc gia cc thi XR-XL=0.

> @

F

' tan sin + cos

sin D + F

' tan sin u + sin 'c - W

= NID

D

ZIDEDE

(4-15)

Biu thc tnh n nh theo ph|ng php Bishop n gin

> @

> @> @ Aa Dd kWe + f

F

' tan sin + cos

sin D + F


- Wx

' tan R u -

F

' tan sin + cos

sin D + F


+ R'c

= Fm

rrID

D

ZIDEDE

I

EID

D

ZIDEDE

E

(4-16)

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Biu thc tnh n nh theo ph|ng php Janbu n gin

> @

> @> @ A cos D - kW + sin

F

' tan sin + cos

sin D + F


cos ' tan u -

F

' tan sin + cos

sin D + F


+ cos 'c

= Ff

rZDID

D

ZIDEDE

DI

E

IDD

ZIDEDE

DE

(4-17) Trong cc biu thc tnh n nh trn, biu thc (4-14) - ph|ng php Fellenius (Ordinary) xy dng theo cn bng m men v b qua nh h|ng ca lc t|ng tc theo ph|ng ng v ph|ng ngang thi, nn th|ng cho kt qu thin nh. B qua nh h|ng ca chnh lch lc t|ng tc theo ph|ng tip tuyn ti hai mt bn (XR-XL=0) v xt cn bng lc v m men l ph|ng php Jan Bu n gin v ph|ng php Bishop n gin. Hai ph|ng php ny hin |c s dng rng ri trn th gii, kin ngh s dng hai ph|ng php ny tnh v chn h s nh nht. 4.6. Ph lc cc tiu chun s dng cho cng trnh tm

1). Tiu chun thit k chuyn ngnh phn xy dng thit k knh thi cng v quy, cc tnh ton thit k phi tun th

theo cc Tiu chun ca Vit Nam v cc tiu chun v h|ng dn chuyn ngnh ca Lin X c |c php s dng Vit Nam.

Danh sch cc Tiu chun Vit Nam v n|c ngoi |c lit k chi tit d|i y.

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2) Cc tiu chun thit k ca Vit Nam

TT S hiu Tn tiu chun

1 TCXDVN 285 : 2002 Cng trnh thu li, cc qui nh ch yu v thit k

2 QPTL.C-1-78 Qui phm ti trng v lc tc ng ln cng trnh thy li

3 TCVN 4253 86 Nn cc cng trnh thu cng tiu chun thit k.

4 14 TCN-56-88 Thit k p b tng v b tng ct thp

5 TCXDVN 4116 : 85 Kt cu b tng v b tng ct thp thu cng tiu chun thit k

6 QPVN 11-77 Qui phm thit k p t m nn

7 QPTL.C-8-76 Qui phm tnh ton thy lc p trn

8 QPTL.C-1-75 Qui phm tnh ton thy lc cng d|i su

9 QTTL.C-1-75 Qui trnh tnh ton tn tht dc theo chiu di |ng dn

10 14.TCN-81-90 Qui phm tnh ton thy lc cng trnh x kiu h

11 14 TCN 57 : 88 Qui trnh thit k dn dng, lp dng

3). Cc tiu chun thit k v h|ng dn tnh ton ca Nga

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TT S hiu Tn tiu chun

1

CHu3 2.06.01-86

=b^jhl_ogbq_kdb_ khhjm`_gby. Hkgh\gu_

iheh`_gby ijh_dlbjh\Zgby.

Cng trnh thu cng, cc quy nh ch yu v thit k UBNN v cc tiu chun Lin X

2

CHu3 II-57-75

*/ABA 57

Kljhbl_evgu_ ghjfu b ijZ\beZ

GZ]jmadb b \ha^_ckl\by gZ ]b^jhl_ogbq_kdb_

khhjm`_gby (\hegh\u_ e_^h\u_ b hl km^h\)

Ti trng v lc tc ng ln cng trnh thu cng

3

CHu3 2.02.02-85 Hkgh\Zgby ]b^jhl_ogbq_kdbo khhjm`_gbc Nn cng trnh thu cng UBNN v cc tiu chun Lin X

4 CHu3 2.06.06-85 Iehlbgu [_lhggu_ b `_e_ah[_lhggu_ p b tng v b tng ct thp

5 CHu3 2.06.05-84 Iehlbgu ba ]jmglh\uo fZl_jbZeh\ p vt liu a ph|ng

6

CHu3 2.06.08-87

;_lhggu_ b `_e_ah[_lhggu_ dhgkljmdpbb

]b^jhl_ogbq_kdbo khhjm`_gbc

Cc kt cu b tng v b tng ct thp ca cc cng trnh thu cng

7

BCH 02-73

MdZaZgby ih ijh_dlbjh\Zgbx

ijhlb\hnbevljZpbhgguo mkljhckl\ ih^a_fgh]h

dhglmjZ [_lhgguo iehlbg k lj_sbgZfb

l_dlhgbq_kdh]h ijhbkoh`^_gby

H|ng dn v thit k cc kt cu chng thm |ng vin ngm ca p b tng c cc khe nt kin to A nng l|ng 1974

8 CHu3 II-7-81 Kljhbl_evkl\h \ k_ckfbq_kdbo jZchgZo Xy dng vng a chn

9 CHu3 3-07.01-85 =b^jhl_ogbq_kdb_ khhjm`_gby j_qgu_ Cc cng trnh thu cng trn sng

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