Li ni u

Li ni u

TCXDVN 286 : 2003 thay th mt phn cho mc 7 TCXD 79 : 1980.

TCXDVN 286 : 2003 do Vin Khoa hc Cng ngh Xy dng bin son, V Khoa hc Cng ngh B Xy dng trnh duyt, B trng B Xy dng ban hnh theo Quyt nh s:.....14...ngy: ...05...thng......6.... nm 2003

MC LC

1. Phm vi p dng 4

2. Tiu chun vin dn 4

3. Quy nh chung 4

4. Vt liu cc6

4.1 Cc b tng ct thp 6

4.2 Cc thp 7

5. H cc bng ba ng v ba rung 8

6. H cc bng phng php p tnh 16

7. Gim st v nghim thu 18

8. An ton lao ng 19

Ph lc A - Nht k h cc 20

Ph lc B - H hng cc b tng ct thp khi ng 26

Ph lc C - Xc nh ng sut ng trong cc BTCT khi ng 28

Ph lc D - Cu to m cc 35

Ph lc E - Biu ghi chi ng cc 37

(((((((((((((((((((((((((((((((((((((((TIU CHUN XY DNG VIT NAM TCXDVN 286 : 2003

(((((((((((((((((((((((((((((((((((((((

Sot xt ln 1

ng v p cc - Tiu chun thi cng v nghim thu

Pile driving and static jacking works - Standart for construction, check and acceptance

1. Phm vi p dng

Tiu chun thi cng v nghim thu cng tc ng v p cc p dng cho cc cng trnh xy dng thuc lnh vc xy dng, giao thng, thu li, thay th mt phn cho mc 7: Mng cc v tng vy cc vn ca TCXD 79: 1980.

Nhng cng trnh c iu kin a cht cng trnh c bit nh vng c hang cc-t, mi nghing, cng... m cha cp n trong tiu chun ny s c thi cng v nghim thu theo yu cu ca Thit k, hoc do T vn ngh vi s chp thun ca Ch u t.

2. Tiu chun vin dn

TCVN 4453 : 1995: Kt cu b tng v b tng ct thp ton khi - Quy phm thi cng v nghim thu.

TCVN 205: 1998: Mng cc-Tiu chun thit k

TCVN 4091 : 1985 : Nghim thu cc cng trnh xy dng.

3. Quy nh chung

3.1 Cc thut ng v nh ngha

3.1.1 Cc ng l cc c h bng nng lng ng( va p, rung).

3.1.2 Cc p l cc c h bng nng lng tnh, khng gy nn xung lng ln u cc.

3.1.3 chi ca cc ng l ln ca cc di mt nht ba ng v 1 pht lm vic ca ba rung.

3.1.4 Ti trng thit k l gi tr ti trng do Thit k d tnh tc dng ln cc.

3.1.5 Lc p nh nht (Pep) min l lc p do Thit k quy nh m bo ti trng thit k ln cc, thng thng ly bng 150 ( 200% ti trng thit k;

3.1.6 Lc p ln nht (Pep)max l lc p do Thit k quy nh, khng vt qu sc chu ti ca vt liu cc; c tnh ton theo kt qu xuyn tnh, khi khng c kt qu ny th thng ly bng 200 - 300% ti trng thit k.

3.2 Thi cng h cc cn tun theo bn v thit k thi cng, trong bao gm: d liu v b tr cc cng trnh hin c v cng trnh ngm; ng cp in c ch dn su lp t ng dy ti in v bin php bo v chng; danh mc cc my mc, thit b; trnh t v tin thi cng; cc bin php m bo an ton lao ng v v sinh mi trng; bn v b tr mt bng thi cng k c in nc v cc hng mc tm thi phc v thi cng.

c y s liu cho thi cng mng cc, nht l trong iu kin a cht phc tp, khi cn thit Nh thu phi tin hnh ng , p cc cc th v tin hnh th nghim cc bng ti trng ng hoc ti trng tnh theo cng ca T vn hoc Thit k ra.

3.3 Trc c nh v cc trc mng cn c tin hnh t cc mc chun theo ng quy nh hin hnh. Mc nh v trc thng lm bng cc cc ng, nm cch trc ngoi cng ca mng khng t hn 10 m. Trong bin bn bn giao mc nh v phi c s b tr mc cng to ca chng cng nh cao ca cc mc chun dn t li cao trnh thnh ph hoc quc gia. Vic nh v tng cc trong qu trnh thi cng phi do cc trc c vin c kinh nghim tin hnh di s gim st ca k thut thi cng cc pha Nh thu v trong cc cng trnh quan trng phi c T vn gim st kim tra. chun ca li trc nh v phi thng xuyn c kim tra, c bit khi c mt mc b chuyn dch th cn c kim tra ngay. sai lch ca cc trc so vi thit k khng c vt qu 1cm trn 100 m chiu di tuyn.

3.4Chuyn ch, bo qun, nng dng cc vo v tr h cc phi tun th cc bin php chng h hi cc. Khi chuyn ch cc b tng ct thp(BTCT) cng nh khi sp xp xung bi tp kt phi c h con k bng g pha di cc mc cu. Nghim cm vic ln hoc ko cc BTCT bng dy.

3.5Cng tc chun b

3.5.1Nh thu cn c vo h s thit k, yu cu ca Ch u t v iu kin mi trng c th lp bin php thi cng cc trong nn lu lm r cc iu sau:

a) cng ngh thi cng ng/ p;

b) thit b d nh chn;

c) k hoch m bo cht lng, trong nu r trnh t h cc da theo iu kin t nn, cch b tr i cc, s lng cc trong i, phng php kim tra thng ng, kim tra mi hn, cch o chi, bin php an ton v m bo v sinh mi trng...;

d) d kin s c v cch x l;

e) tin thi cng....

3.5.2Trc khi thi cng h cc cn tin hnh cc cng tc chun b sau y:

a) nghin cu iu kin a cht cng trnh v a cht thu vn, chiu dy, th nm v c trng c l ca chng;

b) thm d kh nng c cc chng ngi di t c bin php loi b chng, s c mt ca cng trnh ngm v cng trnh ln cn c bin php phng nga nh hng xu n chng;

c) xem xt iu kin mi trng th ( ting n v chn ng) theo tiu chun mi trng lin quan khi thi cng gn khu dn c v cng trnh c sn;

d) nghim thu mt bng thi cng;

e) lp li trc c nh v cc trc mng v to cc cc cn thi cng trn mt bng;

f) kim tra chng ch xut xng ca cc;

g) kim tra kch thc thc t ca cc;

h) chuyn ch v sp xp cc trn mt bng thi cng;

i) nh du chia on ln thn cc theo chiu di cc;

k) t hp cc on cc trn mt t thnh cy cc theo thit k;

l) t my trc c theo di thng ng ca cc v o chi ca cc.

3.6Hn ni cc on cc

3.6.1 Ch bt u hn ni cc on cc khi:

- kch thc cc bn m ng vi thit k;

- trc ca on cc c kim tra thng ng theo hai phng vung gc vi nhau;

- b mt u hai on cc ni phi tip xc kht vi nhau.

3.6.2ng hn mi ni cc phi m bo ng quy nh ca thit k v chu lc, khng c c nhng khuyt tt sau y:

- kch thc ng hn sai lch so vi thit k;

- chiu cao hoc chiu rng ca mi hn khng ng u;

- ng hn khng thng, b mt mi hn b r, khng ngu, qu nhit, c chy loang, ln x, b nt...

3.6.3 Ch c tip tc h cc khi kim tra mi ni hn khng c khuyt tt.

4. Vt liu cc

4.1Cc b tng ct thp

4.1.1Cc b tng ct thp c th l cc rng, tit din vnh khuyn ( c ly tm) hoc cc c, tit din a gic u hoc vung ( c bng vn khun thng thng). B tng cc phi m bo mc thit k, cc c nghim thu theo tiu chun TCVN 4453 : 1995

4.1.2Kim tra cc ti ni sn xut gm cc khu sau y:

a) Vt liu :

- chng ch xut xng ca ct thp, xi mng; kt qu th nghim kim tra mu thp, v ct liu ct, (si), xi mng, nc theo cc tiu chun hin hnh;

- cp phi b tng;

- kt qu th nghim mu b tng;

- ng knh ct thp chu lc;

- ng knh, bc ct ai;

- li thp tng cng v vnh thp b u cc;

- mi hn ct thp ch vo vnh thp;

- s ng u ca lp b tng bo v;

b) kch thc hnh hc :

- s cn xng ca ct thp trong tit din cc;

- kch thc tit din cc;

- vung gc ca tit din cc u cc vi trc;

- chm u n ca mi cc;

4.1.3Khng dng cc on cc c sai lch v kch thc vt qu quy nh trong bng 1, v cc on cc c vt nt rng hn 0.2 mm. su vt nt gc khng qu 10 mm, tng din tch do lm, st gc v r t ong khng qu 5% tng din tch b mt cc v khng qu tp trung.

Bng 1- sai lch cho php v kch thc cc

TTKch thc cu to sai lch cho php

123

1Chiu di on cc, m ( 10( 30 mm

2Kch thc cnh (ng knh ngoi) tit din ca cc c (hoc rng gia)+ 5 mm

3Chiu di mi cc( 30 mm

4 cong ca cc (li hoc lm)10 mm

5 vng ca on cc1/100 chiu di t cc

6 lch mi cc khi tm10 mm

7Gc nghing ca mt u cc vi mt phng thng gc trc cc:

- cc tit din a gicnghing 1%

- cc trnnghing 0.5%

8Khong cch t tm mc treo n u on cc( 50 mm

9 lch ca mc treo so vi trc cc20 mm

10Chiu dy ca lp b tng bo v( 5 mm

11Bc ct thp xon hoc ct thp ai( 10 mm

12Khong cch gia cc thanh ct thp ch( 10 mm

13ng knh cc rng( 5 mm

14Chiu dy thnh l( 5 mm

15Kch thc l rng so vi tim cc ( 5 mm

4.2 Cc thp

4.2.1 Cc thp thng c ch to t thp ng hoc thp hnh cn nng. Chiu di cc on cc chn theo kch thc ca khng gian thi cng cng nh kch thc v nng lc ca thit b h cc.

4.2.2 Mt u cc on cc phi phng v vung gc vi trc cc, nghing khng qu 1%.

4.2.3 Chiu dy ca cc thp ly theo quy nh ca thit k thng bng chiu dy chu lc theo tnh ton cng vi chiu dy chu n mn.

4.2.4 Trong trng hp cn thit c th thc hin lp bo v bng phun va xi mng mc cao, cht do hoc phng php in ho.

4.2.5 Cc on cc thp c ni hn, chiu cao v chiu di ng hn phi tun theo thit k.

5. H cc bng ba ng v ba rung

5.1 Tu theo nng lc trang thit b hin c, iu kin a cht cng trnh, quy nh ca Thit k v chiu su h cc v chi quy nh Nh thu c th la chn thit b h cc ph hp. Nguyn tc la chn ba nh sau:

a) c nng lng h cc n chiu su thit k vi chi quy nh trong thit k, xuyn qua cc lp t dy k c tng kp cng;

b) gy nn ng sut ng khng ln hn ng sut ng cho php ca cc hn ch kh nng gy nt cc;

c) tng s nht p hoc tng thi gian h cc lin tc khng c vt qu gi tr khng ch trong thit k ngn nga hin tng cc b mi;

d) chi ca cc khng nn qu nh c th lm hng u ba.

5.2 La chn ba ng cc theo kh nng chu ti ca cc trong thit k v trng lng cc. Nng lng cn thit ti thiu ca nht ba p E c xc nh theo cng thc:

E = 1.75 a P (1)

trong : E - Nng lng p ca ba, kGm;

a - h s bng 25 kG.m/tn

P - kh nng chu ti ca cc, tn, quy nh trong thit k.

Loi ba c chn vi nng lng nht p Ett phi tho mn iu kin:

(2)

trong :k - h s quy nh trong bng 2;

Qn - trng lng ton phn ca ba, kG;

q - trng lng cc (gm c trng lng m v m u cc), kG

i vi ba i--zen, gi tr tnh ton nng lng p ly bng:

i vi ba ngEtt = 0.9 QH

i vi ba cnEtt = 0.4 QH

Q - trng lng phn p ca ba, kG;

H - chiu cao ri thc t phn p ba khi ng giai on cui, i vi ba ng H= 2.8 m; i vi ba cn c trng lng phn p l 1250, 1800 v 2500 kG th H tng ng l 1.7; 2 v 2.2 m.

Bng 2- H s chn ba ng

Loi baH s k

Ba i--zen kiu ng v song ng

Ba n ng v i--zen kiu cn

Ba treo6

5

3

Ch thch: Khi h cc bng phng php xi nc th cc h s ni trn c tng thm 1.5.

5.3 Khi cn phi ng xuyn qua cc lp t cht nn dng cc ba c nng lng p ln hn cc tr s tnh ton theo cc cng thc (1) v (2), hoc c th dng bin php khoan dn trc khi ng hoc bin php xi nc.

Khi chn ba ng cc xin nn tng nng lng p tnh theo cng thc (1) vi h s k1 cho trong bng 3.

Bng 3- H s chn ba ng cc xin

nghing ca ccH s k1

5:1

4:1

3:1

2:1

1:11.1

1.15

1.25

1.4

1.7

5.4 Loi ba rung h cc chn theo t s K0 / Qt tu thuc vo iu kin t nn v chiu su h cc.

K0 - m men lch tm, T.cm;

Qt - trng lng ton phn gm trng lng cc, ba rung v m u cc, tn.

Gi tr ca t s ny khi dng ba rung vi tc quay bnh lch tm 300(500 vng/ pht khng c nh hn tr s cho trong bng 4.

Bng 4 -T s K0 / QtTnh cht t m

cc xuyn quaPhng php hK0/Qt khi su h cc

< 15 m>15 m

Ct no nc, bn, st do mm v do chy

Ct m, t st, st do mm, cng

St cng, na cng, ct, si, snKhng xi nc v ly t ra khi cc

Xi nc tun hon v ly t khi lng cc ng

Xi nc v ly t khi lng cc thp hn c mi cc0.80

1.10

1.301.0

1.30

1.60

Ch thch: Khi chn ba rung h cc ng c ng knh ln hn 1.2 m nn u tin cho cc my c l thot a t t trong lng cc ng ra ngoi m khng phi tho lp my. Trong trng hp cn rung h cc cc ng knh ln nn dng hai ba rung ghp i ng b trn mt trung chuyn; khi cc gi tr K0 v Qt phi l tng cc ch tiu tng ng ca hai ba rung.

5.5 Khi rung h cc trn rng hoc cc dng tm cn c cc bin php chng kh nng xut hin cc vt nt hoc h hng cc:

- trnh s tng p sut khng kh trong lng cc do y kht nn dng chp u cc c cc l hng c tng din tch khng t hn 0.5% din tch tit din ngang ca cc;

- trnh sinh ra p lc thu ng nguy him ca nc trong t lng cc c th gy nt rn cc-ng BTCT phi c bin php ht nc hoc truyn khng kh.

c th d bo trc nhng h hng c th xy ra khi rung h cc- ng nn dng thit b o gia tc, trong trng hp khng c thit b th tin hnh quan st mc tiu tn cng sut ba ( hoc in nng) v bin giao ng ca cc. Nu thy cng sut ba v bin giao ng ca cc tng, lin kt ba rung v u cc vn kht m tc h cc li b gim th chng t mi cc gp chng ngi; khi cn dng my, tm cch loi b chng ngi bng cch ly t lng cc v bm ra y cc.

Khi rung h cc trong ct v ct giai on cui th nn gim tn s v rung cc trong khong 7(10 pht su thit k lm cht t trong lng v xung quanh cc.

5.6 Khi rung h cc bnh thng tc l cc thng s ba rung n nh, cc khng gp chng ngi th theo s tng tin ca chiu su, tc h cc, bin giao ng v cng sut my s b gim do ma st bn ca cc tng dn. tng chiu su h cc nn tng cng sut ng c cho n cng sut thit k. Khi tc h cc gim ti 2-5 cm/ pht v bin giao ng khong 5mm th cc s kh xung tip; cn phi tin hnh xi nc hoc ly t lng cc cng vi vic chy ht cng sut ng c.

5.7 Khi ng cc bng ba phi dng m cc v m g ph hp vi tit din ngang ca cc. Cc khe h gia mt bn ca cc v thnh m cc mi bn khng nn vt qu 1 cm.

Cn phi sit cht cng ba rung h cc vi cc.

Khi ni cc on cc trn rng v cc -ng phi m bo ng tm ca chng. Khi cn thit phi dng b g c nh v thit b dn hng tng chnh xc.

Khi thi cng cc vng sng nc nn tin hnh khi sng khng cao hn cp 2. Cc phng tin ni cn c neo gi chc chn.

5.8 Trong qu trnh h cc cn ghi chp nht k theo mu in sn (c th xem ph lc A).

ng 5(20 cc u tin cc im khc nhau trn khu vc xy dng phi tin hnh cn thn c ghi chp s nht ba cho tng mt chiu su v ly chi cho lot ba cui cng. Nh thu nn dng th nghim phn tch sng ng sut trong cc( PDA) kim tra vic la chn ba v kh nng ng ca ba trong cc iu kin xc nh( t nn, ba, cc...)

5.9 Vo cui qu trnh ng cc khi chi gn t ti tr s thit k th vic ng cc bng ba n ng phi tin hnh tng nht d theo di chi cho mi nht; khi ng bng ba hi song ng cn phi o ln ca cc, tn s p ca ba v p lc hi cho tng pht; khi dng ba di--zen th chi c xc nh t tr trung bnh ca lot 10 nht sau cng.

Cc khng t chi thit k th cn phi ng b kim tra sau khi c ngh theo quy nh. Trong trung hp chi khi ng kim tra vn ln hn chi thit k th T vn v Thit k nn cho tin hnh th tnh cc v hiu chnh li mt phn hoc ton b thit k mng cc.

5.10 Trong giai on u khi ng cc bng ba n ng nn ghi s nht ba v cao ri ba trung bnh cc i c 1m; khi dng ba hi th ghi p lc hi trung bnh v thi gian cc i c 1m v tn s nht p trong mt pht. chi phi o vi chnh xc ti 1mm.

chi kim tra c o cho 3 lot ba cui cng. i vi ba n v ba i--zen th mt lot l 10 nht; i vi ba hi th mt lot l s nht ba trong thi gian 2 pht; i vi ba rung 1 lot cng l thi gian ba lm vic trong 2 pht.

Thi gian ngh ca cc trc khi ng kim tra ph thuc vo tnh cht cc lp t xung quanh v di mi cc nhng khng nh hn:

a) 3 ngy khi ng qua t ct;

b) 6 ngy khi ng qua t st.

5.11 Trong trng hp khi thi cng thay i cc thng s ca ba hoc cc c ch dn trong thit kth chi d, e, lc ng hoc ng kim tra phi tho mn iu kin:

(3)

Nu chi d ,e, nh hn 0.2 cm( vi iu kin l ba dng ng ph hp vi yu cu iu 4.1), th chi ton phn( bng tng chi n hi v chi d) phi tho mn iu kin:

(4)

Trong cc cng thc trn:

e - chi d, cm, bng ln ca cc do mt nht ba ng v 1 pht lm vic ca ba rung;

c - chi n hi( chuyn v n hi ca t v cc), cm, c xc nh bng dng c o chi;

n - h s tra theo bng 5, T/ m2;

Bng 5- H s n

Loi ccH s n (T/m2)

Cc BTCT c m

Cc thp c m150

500

F - din tch theo chu vi ngoi ca cc c hoc rng( khng ph thuc vo cc c hay khng c mi nhn), m2;

Ett - nng lng tnh ton ca nht p, tn.cm, ly theo iu 2.1 cho ba i--zen, ba treo v ba n ng ly bng QH, khi dng ba hi song ng ly theo l lch my, i vi ba rung ly theo nng lng nht p quy i, cho trong bng 6;

Bng 6 - Nng lng quy i

Lc cng bc

(tn)1020304050607080

Nng lng nht

p quy i(T.cm)450900130017502200265031003500

Q - trng lng phn p ca ba, T;

H - chiu cao ri thc t phn p ca ba, cm;

k - h s an ton v t, ly k= 1.4 trong cng thc(3) v k= 1.25 trong cng thc (4); cn trong xy dng cu khi s lng cc trong tr ln hn 20 th k = 1.4, t 11( 20 cc th k = 1.6, t 6 ( 10 cc th k = 1.65, t 1( 5 cc th k = 1.75;

P - kh nng chu ti ca cc theo thit k, T;

M - h s ly bng 1 cho ba ng v theo bng 7 cho ba rung;

QT - trng lng ton phn ca ba hoc ba rung, T;

( - h s phc hi va p, ly (2 = 0.2 khi ng cc BTCT v cc thp c dng m cc m g, cn khi dng ba rung th (2 = 0;

q - trng lng cc v m cc, T;

q1 - trng lng cc m, tn; khi dng ba rung q1 = 0;

h - chiu cao cho ba i--zen h = 50cm, cc loi khc h = 0;

( - din tch mt bn ca cc, m2;

n0 v n( - cc h s chuyn i t sc khng ng ca t sang sc khng tnh, n( = 0.25 giy.m/ tn; n0 = 0.0025 giy.m/ tn;

g - gia tc trng trng( g = 9.81m/ gy2)

Khi tnh theo cng thc ng Hilley rt gn th chi c th kim tra theo cng thc:

(4a)

e - chi ca cc( tnh trung bnh cho 20 cm cui cng), m;

ef - hiu sut c hc ca ba ng cc; mt s gi tr c kin ngh nh sau:

- ba ri t do iu khin t ng, ef = 0.8

- ba i--zen, ef = 0.8

- ba ri t do nng bng cp ti, ef = 0.4

- ba hi n ng, ef = 0.6;

Bng 7: H s M

Loi t di mi ccH s M

Si sn c ln ct

Ct: - ht trung v th

- ht nh cht va

- ct bi cht va

ct do, st v st cng

st v st - na cng

st v st - do cng 1.3

1.2

1.1

1.0

0.9

0.8

0.7

Ch thch: Khi ct cht gi tr h s M c tng thm 60%H - chiu cao ri ba, m;

Wr - trng lng ca ba ng, T;

Qu - kh nng mang ti cc hn ca cc, thng thng ly vi h s an ton Fs ( 3

Lp - chiu di cc, m;

F - din tch tit din cc, m2Ee - m un n hi ca vt liu cc, T/ m2.

5.12 Nu trong thit k mng cc ng c quy nh tm bin giao ng khi sp dng rung cc th bin dao ng cc cc - ng ng knh ngoi n 2m, vi tc h cc t 2 n 20 cm trong 1 pht c tnh theo cng thc:

(5)

trong : A - bin ly bng 1 /2 lc ton phn ca giao ng nhng pht cui trc lc dng rung, cm;

Nn - cng sut hu hiu ton phn giai on cui, KW;

Nx - cng sut vn hnh khng ti, i vi ba rung tn s thp, ly bng 25% cng sut thuyt minh ca ng c in, KW;

nv - tc quay ca b lch trong ba rung, vng / pht;

P - kh nng chu ti ca cc - ng, T;

( - h s ph thuc vo t s gia sc khng ng v sc khng tnh ca t, cho trong bng 8 v bng 9;

Qv - trng lng ca h thng rung, bng tng trng lng ca ba rung v chp u cc.

Bng 8- H s ( cho ct

Tn tH s ( cho t ct

ThVaNh

Ct no nc

Ct m4.5

3.55.0

4.06.0

5.0

Bng 9: H s ( cho st

Tn tH s ( cho t st khi st

IL > 0.750.5