Trng i hc xy dng Thuyt minh n xy dng cuB mn cu hmTHI CNG CC KHOAN NHI I CC,TR T1,T6i.thi cng cc khoan nhi: Thit k chn my khoan.Cn c la chn: ng knh cc v chiu su cc:D=1.0m,L=28.4-15=13.4 m. My mc sn c ca nh thu iu kin a cht(cng chu nn ca t):Mi khoan i qua cc lp sau: Lp4 sa thch dip mu xm ximang, cng cpIII Lp 5- voi mu xm trng c ch vubj thnh st cng cp IV-VI Lp 6- vI mu xm trng phong ha nt n t cng cp VII Thi cng n gin, thit b gn nh. Vy ta quyt nh chn my Kh100 ca hng hitachi, thng s nh sau:

Trng lng 43 T, mmen quay M=4(t/m), ng knh l Dmax= 1.5m su 52m. y s dng bin php khoan tun hon ngch:1. Nguyn tc chung v phng php:a) Khoan tun hon khng s dng ng vch m s dng dung dch khoan chng vch t trong l c gt ph to thnh mn khoan v uc ly ln bng ht kh ng.b) u khoan khng ly ln m lin tc ph y l.c) Trn ming c song dng 1 on ng vch dn hng v nh v.d) Sau khi lng lc t c tch ra khi hn hp cn dung dch khoan c b sung thm hp cht v bm tr li.2. Cc bc tin hnh: s lp t my mc thit b:

+S b chn ba chn ng xung kch c;Mc= 6.0 KNm, = 1468/60= 24.46(1/s), trng lng ba 2.2tn.Tnh lc cn ca t T:

u; l chu vi ca cc u=2**R.i: sc khng thnh bn ca t.=N*a (a=1kPa vi cc khoan nhi, N=20)hi: chiu su chn ng vch h=3m.

Tnh trng lng ca cc, ba, m u cc Q :

Kim tra theo iu kin th nht:

Trong ly cho cc vn thp.Kim tra theo iu kin th hai:

Trong : Kim tra theo iu kin th ba:

V Trong cc h s ly theo cc ng thp:

Vy ta chn ba nh trn la hp l.S thi cng cc cc khoan nhi nh hnh v:

Bc1: Chun b thi cng- Chun b cc ti liu : cc s liu v mt ct a cht ,thu vn,chun b bng tin thi cng cc hng mc v trnh t thi cng - Chun b vt liu : theo yu cu ti thiu thi cng 1 cc khoan nhi v cc dng c kim tra st ca betong,va st Bentonit v chiu su cc. Bc 2 : Rung h ng vch thp - ng vch thp c nhim v gi n nh thnh vch ca h khoan, trnh b st l - ng vch thp phi c chiu di p ng c yu cu :+ Cao hn mc nc thi cng ti thiu 1 m m bo p lc ct dung dch Bentonite lun cao hn mc nc 1 m.+ Chiu su ngm vo t gi ng vch di ti trng thi cng, m bo n nh thnh vch v su hn chiu su xi cc b ti thiu 1 m. + ng vch thp s dng ng vch thp ng knh D = 1,2 m, dy = 10 mm: tnh ton chiu su t ng vch;Cao nh ng ly the max ca hai gi tr: cao hn CTN 0.3m hoc cao hn mc nc ngm (MNN) 0.2m.

ch tiu t nn: trng lng th tch = 2.6(kN/m3). H s rng e= 0.6. Gc ni ma sat ch tiu va st: v= 1.1 (kN/m3) dung trng va. Cng tI trng mt t q tra bng c q=30 (MPa) ly tng trng lng xe cu my l 100kN [theo [2] trang 138]Gi thit ng nm trong 1 lp t, chiu dy lp t pha trn MNN l y=1m: y=CTN-MNN=1mp lc ch ng ti chn cc: pa=[(q+*y)+(H-y)*dn]a dntrng lng y ni t nn dn= 0= 27kN/m3 a= tg2(450-)a : chiu cao nh ln khi mt nc ca ng vch: a= CN-CTN =0.3m.Phng trnh cn bng p lc: (H+a) v = [(q+ *y)+(H-y))*dn]aGii ra ta c: H= 2m. Chiu di ng vch L=H+a= 2.3m. + nh v cc trn thanh thp tm, nh v chu vi ngoi ng vch v hn cc thanh thp hnh 4 xung quanh nh v chc chn v tr ng vch thp.+ Cu t ng vch vo v tr c nh v rung h ng vch xung cao thit k. Kt hp gia ba rung v khoan mi h ng vch n cao yu cu.+ Kim tra cc sai s : cc sai s khi h ng vch phI nm trong gii hn nghing 1% Sai s to trn mt bng 8cm + Tin hnh khoan h ton b cc ng vch ca 1 hng cc vi trnh t nh trn. Bc 3 : Khoan to l nh v tim cc khoan nhi bng my kinh v ,nh du tim cc .nh v chnh xc tm ca ng vch trng vi tim cc . Dng cn cu v ba rung h on ng vch .Rung h ng vch n cao thit k, Trong qu trnh rung h phI thng xuyn kim tra v tr tim cc, thng ng vch theo cc sai s gii hn nh trn Trong qu trnh khoan cn ch trnh cc tc ng lm x dch lm nghing l khoan hoc gy cn khoan. Cn ch theo di vn tc nc chy khi khoan tr do h ni ng ngang sng gy cn nc rt ln.Bc 4 : V sinh h khoan :- Giai on 1 : Sau khi khoan n chiu su thit k, dng khoan 30 pht o lng. lng c xc nh bng chnh lch chiu su gia hai ln o lc khoan xong v sau 30 pht. Nu lng vt qu gii hn cho php th tin hnh x l cn lng bng phng php tun hon nghch cho ti khi t yu cu. Phng php nh sau :

+ Lp u phun vo trong ng b tng c ng knh dn kh 60 nm cch y h khoan 10 m, u ng b tng cch y l khoan khong 1 m.+ Thi kh p lc cao vo ng dn kh, kh nn trn vi mn khoan nng to thnh loi mn nh dng ln theo ng b tng ( ng tremi) ra ngoi; mn khoan nng di y ng tremi li c trn vi kh nn to thnh bn nh; dung dch khoan ti c b xung lin tc b cho mn nng tro ra; qu trnh thi ra tin hnh cho ti khi cc ch tiu ca dung dch khoan ( xem mc Bentonite) v lng t yu cu quy nh.+ u ng thi ra c nng ln v h xung theo cc cao khc nhau trong qu trnh thi.+ Bentonite bn c dn qua b lng; qua my tch ct, v thng cha v c bm cp tr li h khoan.- Giai on 2 : Lm sch ln cui ( sau khi h lng ct thp), tin hnh khi lng y h sau khi lm sch theo giai on 1 vt qu gii hn cho php, lm sch ln cui theo phng php nh trn.+ Khi ly dung dch kim tra phi ly v tr cch y h khoan 0,5 m.+ Cng tc v sinh h khoan c thc hin cho n khi cc thng s ca va Bentonite trong h khoan t n yu cu di y :

* T trng : = 1.05 - 1.15* nht : s = 18 - 45 giy * Hm lng ct : < 6%* PH : 7 - 9+ Lng cht bi lng y h khoan sau khi v sinh h khoan khng c dy qu 5 cm. Bc 5 : Gia cng, lp h lng ct thp - Vt t gia cng lng thp s dng phi ng yu cu thit k.- Lng ct thp cc c ch to sn thnh cc lng theo ng h s thit k sau a ra v tr thi cng t hp v h xung cao thit k.- Cng tc h ct thp phi c tin hnh ngay sau khi v sinh h khoan xong v phi c lm ht sc khn trng gim ti a lng cht lng ng xung y h khoan cng nh kh nng st l thnh vch.- Trong trng hp lng ct thp phi ni bng mi ni hn phi tn dng ti a kh nng ca thit b hn rt ngn thi gian hn ni n mc ti thiu.- Khi h lng ct thp xong phi lm sch l khoan khi lng ng mn vt tiu chun cho php. Bc 6 : Cng tc b tng a- Lp h thng b tng - ng b tng trc khi lp phi c kim tra v sinh sch s, c bit cc mi ni ren, cc mi ni phi c bi m.- Trong qu trnh lp ng phi ghi chp tng hp ng trnh nhm ln v chiu di.- Nu cn thi ra li l khoan th lp u ng thi ra sau khi lp xong ng b tng, h thng thi ra c ch to chuyn dng, vic thi ra c thc hin theo phng php tun hon nghch cho n khi dt yu cu.- Sau khi lp t xong ng b tng, kim tra li hm lng ct trong ng h khoan, nu cha t yu cu ( do lng ) th v sinh li.b- Trn b tng v vn chuyn - B tng c trn bng trm trn t ng, h thng nh lng c sai s khng vt qu sai s cho php ca cc thnh phn.- Thi gian trn ph thuc vo c tnh k thut ca thit b trn.- B tng c s dng cho cc khoan nhi c trn thm ph gia ho do vi t l t 0,8 % n 1,2% tu thuc vo mi trng cng nh c ly vn chuyn. Vi t l ph gia nh vy c th ko di thi gian ninh kt ln n 10 h, m bo thun li cho qu trnh b tng cc khoan nhi.- B tng mc M 300, mu 15 x 15 cm............b tng ch c khi kim tra st ti v tr t 17 20 cm. Ch dn k thut st 18 n 20 cm, lng 18 20 cm.- Khng ch tc gim st ca b tng khng qu 3 cm/gi. Kim tra st ca b tng trc khi xut trm v trc khi b tng vo cc.- S lng kim tra mu b tng :+ Kim tra st : 5 m3/ ln.+ Ly mu th nghim : 100 m3/ 01 t mu nhng khng t hn 01 t mu cho 01 cc.c- b tng cc

- T hp v lp t ng b tng vo trong lng h khoan sao cho ng c t sut chiu di h khoan.- Treo h thng ng b tng ln gi .- Lp cu b tng.- Trc khi b tng phi dng cu nhc h thng ng ln sao cho chn ng cch y h khoan khng qu 25 cm.- Cp b tng vo y phu v tin hnh ct cu, ngay khi ct cu b tng phi c cp lin tc lng to p lc y ct nc trong ng b tng.- Trong qu trnh b tng thng xuyn kim tra cao b tng trong h khoan tin hnh ct ng b tng kp thi, ngm su ca ng trong b tng ti thiu l 1.5 m. Phu v ng b tng phi c lm sch v kn nc.- Trong sut qu trnh b tng cc phi lun c duy tr mt lng b tng cc ln trong ng m bo p xut trong ng > p xut ca nc.- Thi gian b tng cho 1 cc < hoc = 10 h, ( c s dng ph gia chm ng rn). thi gian dng ti a gia cc t b tng khng qu 4 h.- Cao b tng cui cng phi cao hn cao u cc thit k khng nh hn 1.2 m.d - Cc s c v bin php x l s c khi b tng :- Trong qu trnh b tng nu tc ng, tuyt i khng c lc ng b tng. Dng bin php ko ng ln ( chn ng b tng cn ngp trong b tng khong 1.5 m) ri h nhanh ng xung, kp hp dng ba tay g vo ng b tng.- Nu vn tc ng th phi rt ng b tng ra thay ng khc v tin hnh ct cu li. Phi lp bin bn c xc nhn ca TVGS v tr s , cao b tng cc khi xy ra tc ng b tng phi ct cu li.- Bin php ct cu li nh sau :+ chn ng b tng cch mt b tng 20 cm.+ Chun b b tng tin hnh ct cu li nh ln u.+ Khi xc nh b tng ra khi ng tremi th h ng b tng xung ngp vo on b tng t trc, tip tc b tng cc nh bnh thng.Sau khi betng xong th rt ng vch ln.3. Quy nh vt liu :3.1 - Dung dch khoan 3.1.1 - Khi qut :Trong phng php khoan khng c ng chng ngi ta s dng dung dch Bentonite h vch. Bentonite l mt hn hp m thnh phn gm c bt st v cc cht ph gia, trng thi kh, c ng trong cc bao chng m quy cch 25 kg hoc 50 kg/bao. Bentonite c pha ch vi nc sch tiu chun theo t l nht nh ph hp vi tnh hnh a cht l khoan, c th, c a vo l khoan v duy tr trong sut qu trnh khoan. Trong l khoan dung dch Bentonite s thm thu vo lp t thnh vch, to thnh mt lp mng mng. Lp mng ny s bo v b mt thnh vch khi st l. Ngoi tc dng bo v thnh vch, do dung dch Bentonite c t trng v nht cao s ng vai tr l phng tin ti mn khoan t y h khoan n b lng trong phng php khoan tun hon thun.Bentonite c la chn loi l loi Bentonite tho mn cc ch tiu k thut nh bng di 3.1.2 - Sn xut dung dch Bentonite :Dung dch Bentonite c sn xut trn my trn BE - 50 bng cch bm nc sch tiu chun vo bung trn, sau khi ng my trn vn hnh, tip n t t bt Bentonite vo cho s lng cn thit. Sau khong 5 pht, dung dch c trn xong, m van s dung dch vo thng cha. Khi lng dung dch Bentonite sn xut ln u cho 1 cc khoan nhi ti thiu bng th tch l khoan.Dung dch Bentonite sn xut xong 12 gi cho Bentonite trng n ht mi a ra s dng. Trong thi gian ch c 3 n 4 gi dng kh nn xc mt ln, nhm trnh Bentonite tch nc.3.1.3 - Kim sot dung dch Ben tonite :- Th nghim ban u : Bentonite mi nhp v kho hoc tn kho qu 3 thng phi lm cc th nghim ban u xc nh cc ch tiu cn thit lm c s cho s dng, theo bng sau :

Bng : Cc ch tiu dung dch BentoniteTn ch tiuCh tiu tnh nngPhng php kim tra

1- Khi lng ring1.05 ~ 1.15/cm3T trng k hoc bomk

2- nht18 ~ 45 giyPhu tiu chun

3- Hm lng ct< 6%Dng c xc nh hm lng ct

4- T l cht keo> 95%o cc

5- Lng mt nc< 30 cc/30 phtDng c o lng mt nc

6- dy o st1 ~ 3 mm/30 phtTh nghip p thm

7- Lc ct tnh1 pht : 20 ~ 30 mg/ cm210 pht : 50 ~ 100 mg/cm2Lc k ct tnh

8- Tnh n nh< 0,03 g/ cm2

9- PH 7 ~ 9 Giy th PH

- Ch tiu dung dch Bentonite la chn s dng khoan cc l ch tiu c tin cy cao tc l dung dch la chn phi m bo n nh thnh vch khi khoan n tng a cht yu nht.Sau xc nh c cc ch tiu ca dung dch, bt tay vo sn xut i tr phc v khoan cc.- Trong qu trnh khoan dung dch thng xuyn c b xung vo h khoan lun gi mc dung dch trong h cao hn mc nc sng hoc nc ngm t 1.0 n 1.5 mPhi khoan c dung dch Bentonite ti ln, a v qua my tch ct lm sch bn ct, sau s v thng cha trc khi a tr li h khoan.- Trong thi gian khoan to l t nht 1 ngy 2 ln kim tra cc ch tiu ca dung dch Bentonite.+ Thng cha trc khi bm v h khoan + Trong h khoan ( ly ti ca x dng dch v) - Qu trnh khoan, dung dch khoan s thay i theo xu hng : gim nht, tng t trng v ct lng do mn khoan ho trn vo dung dch. Tuy vy vic thay i nht ca dung dch khoan c nh hng ln hn n vic bo v thnh vch. Di y l bn tham kho nht thch hp ca dung dch khoan i vi tng lp a tng c th nh sau :Bng : nht tham kho cho cc loi a tngLoi a tng nht

Khng c nc ngmC nc ngm

St

Bn ct, st pha ct29 - 35

Ct ln bn32 - 3738 - 43

Ct ht mn n th34 - 4041 - 46

Ct si sn39 - 4344 - 50

- iu chnh nht : Trong trng hp mun thay i nht ph hp vi tr s bng 3 ngi ta phi iu chnh+ iu chnh tng : Mun tng nht thng thng ngi ta s dng ph gia CMC pha vi t l 0,8 - 1%0 khi lng Bentonite+ iu chnh gim : Mun gim nht ngi ta phi gim tng ng Bentonite pha vo dung dch, tc b xung thm mt s lng dung dch mi sn xut c nht thp hn- Sau khi khoan xong cc, tin hnh v sinh ( lm sch ln 1) h khoan ly ht ct, bn lng trong h khoan v to ra dung dch Bentonite trong h khoan ng nht c cc ch tiu ph hp.- V sinh c tin hnh bng thit b nn, th ng xung y l khoan, ht ln a v my tch ct v t bm b vo h khoan.- Cng vic c thc hin cho n khi mu dung dch c ly ln t y h khoan t c cc ch tiu quy nh trong bng cc ch tiu dung dch Bentonite- Ngay sau khi kt thc vic lp t, ta lp li ng v sinh h khoan, v tin hnh lm sch ln 2 cho n khi dung dch t cc ch tiu k trn, tin hnh lp t thit b b tng v b tng.3.1.4 - Thu hi s dng li :Trong qu trnh b tng dung dch Bentonite trong lng cc c thu hi v thng cha s dng li.3.2 - Ct thp thng :Ct thp thng tun theo tiu chun v quy nh ca tiu chun k thut ca d n, c k s t vn chp thun.3.3 - Xi mng :Xi mng : S dng Ximng Porland PC 40, PCB 40 tr ln, ph hp vi cc yu cu ca TCVN v quy nh ca tiu chun k thut ca d n, c k s t vn chp thun.3.4 - Ct liu ht th : :Ngun trc khi s dng phi c ly mu th nghim vt liu v c k s t vn chp thun.3.5 - Ct liu ht mn :Ct : Ngun ct trc khi s dng phi c ly mu th nghim vt liu v c k s t vn chp thun.4. Cng tc kim tra cht lng:4.1 - Kim tra cht lng trong qu trnh khoan4.1.1- Kim tra Bentonite :- Kim tra dung dch Bentonite nhm m bo cho thnh h khoan khi khoan trong tng a cht c nguy c sp vch, m bo dung dch khng qu bn, khng qu long lm nh hng n cht lng b tng cc.- Cht lng Bentonite m bo cc ch tiu trong mc Bentonite.4.1.2- Kim tra l khoan :- Thng s v l khoan cn kim tra nh sau :Bng : cc thng s cn kim tra v l ccThng s kim traPhng php kim tra

Tnh trng l cc- Kim tra bng mt

thng ng v su- Theo chiu di cn khoan v mi khoan- Thc dy- Qu di

Kch thc l- Phng php kim tra kch thc- Theo m ca cnh mi khoan khi m rng y

lng y l- Th chu ( hnh chp nng 1 kg)- So snh su o bng thc dy trc v sau khi vt, thi ra

- Cc sai s v l khoan cc theo quy nh ca quy trnh nh sau :Bng : Sai s cho php v l khoan ccPhng php to l ccSai s thng ngSai s v tr cc ( cm)

Cc bin trong nhm ccCc pha trong nhm cc

Cc gi thnh bng dung dch

D 1000 mm

1%

8

8

Ch thch :Sai s cho php v su h khoan < hc = 10 cm4.2 - Kim tra cht lng b tng :- Kim tra st ca b tng, tt c cc xe b tng trc khi a vo cc.- Kim tra kh nng bm c ca b tng, ct liu th < ng knh cho php ca my bm.- Ly mu th nghim ( 7 ngy v 28 ngy ): Ly 9 mu/ cc4.3- Nhng vn kim tra trc qu trnh b tng :- Bin bn kim tra v sinh h khoan, su, lch, a cht l khoan.- Chng ch cp phi b tng.- Kim tra ct liu trn b tng, st b tng.- Kim tra vic gia cng lp t lng ct thp- Kim tra vic lp t ng b tng4.4 - Nhng vn kim tra trong qu trnh b tng :- Kim tra thi gian trn thc t.- Kim tra st v thi gian duy tr linh ng ca b tng- o c kim tra cao b tng xc nh chiu su ca ng b tng ngp trong b tng kp thi rt v tho ng b tng.- Ghi chp thi gian b tng vo cc : Tng th v chi tit tng cng on.4.5 - Phng php th nghim kim tra cc :- p mu b tng th nghim R 7, R 28 ngy- Dng phng php kim tra bng siu m 100% s lng cc- Kim tra cht lng b tng v mn khoan ti mi cc bng phng php khoan ly li mi cc. Nu dy chuyn n nh, cht lng thi cng tt, c th ch khoan 50% s cc nhng khong nh hn 2 cc/ 1 m, tr.- Cc th nghim khc theo tiu chun k thut v h s thit k.II. THI CNG I CC:II.1 Gii thiu chung:II.1.1 T chc mt bng thi cng Do mt ct ngang cu gn nh i xng nn mt bng b tr hai bn b sng ging nhau. Mc nc thi cng thp +28m Tin hnh ng vng vy cc thp ni tip gip gia cc tr T2,T5 vi mt sng to mt bng thi cng mng cc v i cc ca cc tr T1,T2,T5,T6 trn cn. Do lp t trn cng l sa thch dip mu xm xi mng cng cp III nn sau khi san i mt bng thi cng khng cn m nn m vn m bo cho my thi cng i li r rng.II.1.2 Bin php thi cng chnh Vi tr T1,T2,T5,T6 thi cng cc khoan nhi bng phng php khoan tun hon ngch. Cng vi hai tr T3,T4 ta tin hnh thi cng trn h phao niII.1.3 Cung cp nng lng v nc cho cng trng. in nng ch yu dng cho sinh hot, chiu sang v chy my c ly t trm bin p gn nht. Nc:+ S dng nc sch t ging khoan cho sinh hot hng ngy ca cng nhn v k s phc v cng trng.+ Nc ding cho thi cng v trn vt liu c ly trc tip t sng.+ Dng xe chuyn ch nc c cha thit b bm ht v ti.

II. 2 Tnh ton v chn vn khun i:

Cu to vn khun i cc nh hnh v : Xc nh ti trng tnh ton Din tch i cc l: F = 4.5x7= 31.5 m2 Chiu cao i cc l : l = 2 m. Chn my trn b tng loi JS1000, ta s dng 2 my khi b tng i cc. Cng sut trn b tng l :W= 50 m3 /h Vy trong 4h c th trn c l: V= 200m3 Chiu cao lp b tng m my c th trn trong 4h l: H = 1,16 m. Khi trn b tng c m di c bn knh tc dng l : R = 0,70 m.

p lc ngang ca b tng ti c tnh theo cng thc Pmax=(q+.R).n (T/m2)My trn c dung tch ca thng V=1,0 m3 R=0,70 m l bn knh tc ng ca m di. n=1,3 l h s vt ti. =2,4 T/m2 l trng lng ring ca btng.Ti trng tc dng vo vn khun qsuy i l: p lc do m ngang gy ra: q=.R = 1,68 (T/m2). Lc xung kch khi b tng: q= 0,6 T/m2 Ptc=(0.6+2.4x0,7) = 2.28 T/m2 => Pmax=(0.6+2.4x0,7)x1.3 = 2.964 T/m2Vy p lc qui i:

Pq = = = Pq = 1.65 (T/m2). II.2.1. Tnh ton vn khun ng : Tnh cho 1m di vn khun ng.Vn khun ng c tnh nh dm lin tc k ln cc np ngang c chiu di tnh ton bng khong cch gia cc np ngang l=1,0 m

Mmen un ln nht ti tit din gia nhp :

Mmax = = = 0.165 (T.m)Chn vn g rng b =50cm.Chiu dy vn ng uc chn m bo iu kin v cng :

=> => m = 3,97 cm.Trong :

+ : Chiu dy tm vn ng

+ : Cng chu un ca g : Kg/cm2 = 1800 T/m2

Vy chn chiu dy vn ng l : =5 cm.Sau khi chn c chiu dy vn ng ta phi kim tra vng ca vn ng, vng ca vn ng c xt n tnh lin tc ca vn c tnh theo cng thc sau :

Trong : + E : Mun n hi ca g E =105 Kg/cm2 = 106 T/m2. + I : Mmen qun tnh ca vn ng :

(cm4).

+ : p lc ngang quy i tiu chun. (T/m2).

+ [f]: vng cho php i vi vn ng th cm.

m = 0.192 cm. => f = 0,276 cm < [f] = 0,4 cm tha mn.Vy vn ng chn m bo v cng v vng.II.2.2.Tnh np ngang Np ngang c k ln cc np ng do np ngang nh 1 dm lin tc k ln cc np ng, p lc btng tc dng ln cc vn ng li c k ln np ngang do np ngang np ngang s chu tc dng ca p lc Pq nh hnh v:Khong cch gia cc np ng : a =1,5 m.

Ti trng tnh ton phn b u vo thanh np ngang:q = Pq .l = 1.65x.1,0= 1.65T/m.Thanh np ngang lm vic theo s dm lin tc, do mmen tnh ton tc dng ln np ngang c tnh nh sau :

Mmax=== 0.37125 Tm = 37125 Kg.cmChn tit din np ngang l : 10x15 cm.

Kim tra iu kin bn :

Ta c : W = (cm2).

=> = Kg/cm2 < Ru=180 Kg/cm2 . OK.II.2.3. Tnh ton np ngNp ng c coi nh dm lin tc k ln cc thanh chng v thanh ging nhng ti cc ch giao nhau gia np ng v np ngang ta u b tr thanh ging hoc thanh chng nn ta ch cn chn thanh ng m khng cn tnh ton. tin cho cng tc chun b vt liu thit b, ta chn tit din thanh np ng ging nh thanh np ngang c tit din :10x15 cm.II.2.4. Tnh ton thanh cng Cc thanh cng chu lc ko do p lc ca btng. Lc ko ny t l thun vi din tch phn vn khun gii hn bi cc ng chia i khong cch cc thanh cng. Do lc ko trong thanh cng c xc nh theo cng thc sau: T = Pq. FalTrong : Fal =1.2 = 2,0 m2. => T = 1.65x2,0 = 3.3 T = 3300 KgTa dng thp AII c R=2800 Kg/cm2 nn din tch ct thp cn thit l:

cm2Thanh cng chn bng thp 12.

II.3 trnh t thi cng: II.2.1 Thi cng mt bng; II.2.1.1 thi cng bng my;Mt bng thi cng c san bng my i v khng cn m n cao +29m( trn mc nc thi cng 1m) theo s sau;

Ch thch: + 1.Mt bng o bng my i. + 2.Ta luy nn o vi m=1 do lp th 2 st trng thi na cng. + 3. ng ly t ca my i. Chn my thi cng gm:a) My i, s lng my tnh theo tin thi cng v nng sut my ( trang 198[3]). y chn my komatsu D50A;

Sn lng gi my: Qh = (m3/h) (1)Sn lng ca my : Qca= 7.5*Qh* Kt (m3/h) (2) Trong :q- lng t mt ln y tra theo bng, q=1m3Tv- thi gian t v tr ly t n v tr t [trang 40 [4]]( s).

Tv=+2tquay+thaben+mtsang s Li,vi on ng vn tc ca cc on : ct t, vn chuyn, v i v; tquay=10s thi gian quay vng; tha ben=1-2s thi gian h ben; tsang s= 4-5s; m s ln sang s;Tv=45+10+1+4=60s.Kp- h s ri, Kp= 1,3 ( Theo bng 1[4])7.5- thi gian lm vic ca my ( tnh 0.5 gi cho bo dng, bn giao my trc v sau khi lm vic).Kt- h s s dng thi gian ca my(0.72-0.75)

T (1) Qh= = 45.15 ( m3/h).Sn lng ca my: Qca= 7.5*45.15*0.75= 254 (m3/h). Khi lng t V=Vc*1.3Trong :+ Vc th tch thc ca t: s b chn Vc =400 m3+1.3 l h s ti xp. V=400*1.3= 520 (m3).S ca my cn dng: C=Qca/V= 520/254= 2 (ca).II.2.1.2 Thi cng bng th cng; Sau khi dn xong mt bng bng my i ta cho cng nhn o th cng hnh dng h mng c ta luy v rng thot nc, kch thc mng nh hnh di:

Tin hnh p u cc bng tay n cao d thit k v v sinh h mng tht sch, tin hnh lp dng vn khun v ct thp cu to sao cho m bo ng yu cu k thut, tin hnh lp thanh chng gi vn khun v btng bng my JS1000 cng sut 50m3/h, tin hnh b tng bng ng , bo dng b tng v tho vn khun.(xem thm bn v).THI CNG CC KHOAN NHI I CC,TR T2,T5I. Thi cng o nh:V thi cng mng nm st b, chiu su ngp nc 800kg/cm2. Hm lng cc tp cht sulphat khng c vt qu 1% trng lng. Hm lng bi , bt ..( th nghim bng phng php ra) khng vt qu 1.5% trng lng. Khng ln t cc, hoc tp cht khc. Hm lng ht mm yu, ht t phong ho khng vt qu 5% trng lng. Cng chu nn v ca trng thi bo ho t nht phi t gp 2 ln cng thit k ca b tng ( mu kch c 5x5x5cm hoc mu tr trn D5x5cm). Hm lng dt khng c vt qu 10% trng lng.b) Ct: Ct dng trong dm cu BTCTDL phi l ht ct th ( ct vng), ht cng sch, phi m bo cc yu cu k thut theo cc tiu chun quy trnh quy phm. Ct liu phi p ng cc yu cu v thnh phn cp phi theo tiu chun vt liu TCVN 1770-86. Ct phi c M un ln khong 2.0 n 2.8 hoc c th ln hn. Hm lng tp cht c hi:+ Hm lng bn t khng c vt qu 2% trng lng ( th nghim bng phng php ra)+ Hm lng mica khng c vt qu 1% trng lng.+ Hm lng cc tp cht sulfua v sunphat (tnh theo S03) khng c qu 1% trng lng.+ Hm lng cht hu c ( xc nh bng phng php so mu) khng c qu mu tiu chun.c) Xi mng : Xi mng dng trn b tng phi l phi l loi xi mng Porland ph hp vi tiu chun TCVN 2682-1992. Xi mng nhp v phi c giy chng ch km theo ca nh sn xut nh: nhn hiu, m hiu, l sn xut... Phi th nghim kim tra cht lng c t theo chng ch hay khng mi c php a vo s dng. Xi mng khng mua d tr trong kho qu 3 thng, nu qu 3 thng phi kim tra th nghim trc khi dng. Khi mua v cn ghi ngy thng, cc l mi c khng c xp cnh nhau. Xi mng mua v cn phi c bo qun ni kh ro, kho cha xi mng cn trnh c ma, l, khng t trc tip trn nn (k c nn gch), xi mng cng phi k cch tng 50cm. Tt c xi mng u phi c cng nn ca mu va ximng tiu chun trong 28 ngy khng nh hn mc xi mng thit k. Xi mng khng t quy cch (qua th nghim nh my hay hin trng) th tt c cc t xi mng nhp kho khng t ngay lp tc nh thu phi mang l vt liu khng c chp nhn ra khi cng trng v thay vo bng loi xi mng p ng c mi quy cch yu cu. Cht lng xi mng phi t cc ch tiu sau: + Thi gian ng cng ca xi mng:Bt u ninh kt khng sm hn 1gi.Thi gian kt thc ninh kt khng sm hn 6 gi.- Tnh n nh th tch ca mc xi mng n nh.d) Nc trn BT: Nc dng trn BT m bo yu cu k thut quy nh trong TCVN 4506-87. Trc khi ly nc t bt k ngun no trn b tng cn phi th nghim, phn tch v mt ho hc. C th dng loi nc ung c m khng cn phi th nghim. Nc c du, m ng thc vt, acid, mui khng c dng b tng. Cc yu cu v mt ho hc (hm lng cc cht qua phn tch) phi m bo t theo yu cu sau:+ Tng lng cc cht mui 100mg/l.+ Hm lng ion S04 3.500mg/l.+ Hm lng ion Clo 100mg/l.+ pH ca nc khng c nh hn 4.f) Yu cu trong qu trnh thi cng b tng: * Vn chuyn: S dng phng tin vn chuyn hp l, trnh hn hp b tng b phn tng, b chy nc xi mng v b mt nc do gi nng. S dng thit b, nhn lc v phng tin vn chuyn cn b tr ph hp vi khi lng, tc trn, v m b tng. Khi dng thng treo vn chuyn hn hp th hn hp b tng vo thng treo khng vt qu 90-95% dung tch thng.* b tng: Khng c b tng vo cp pha t trn cao qu 1.5m. Khi dng ng hoc mng rt th nhng dng c ny phi gi cho sch sao cho b tng khng b ri. B tng phi c vo trong cp pha theo nhng lp c chiu dy khng qu 45cm nu dng thit b m t bn trong, cc trng hp khc chiu dy khng qu 30cm. Mi lp s c trc khi lp trc bt u ng kt. Phi thng xuyn kim tra st ca b tng ti ni trn trc khi b tng. Khi b tng bt u ng kt khng c gy chn ng mnh vo cp pha v khng c dng mt lc no tc ng ln cc u ct thp t trong b tng. Khi b tng lp y mng m phi c bin php phng nga khng cho b tng hp th m hoc cho kh m thm vo. Phi c bin php lm thot nc ng di y rnh. Trong khi ang b tng khng c php bm ht t bn trong cp pha mng. Nu cn trnh nc trn vo th ch h cp pha c bt li bng cch b tng qua 1 ng rt v phi ch cho mi bt b tng ng cng li mi c tip tc. Cc ph kin gn vo dm (bu lng, thanh neo) phi lun c kim tra trong qu trnh v phi nn chnh li nu chng b lch. Phi ch bo m b tng khi rt vo ph kn bn di cc tm ngang, tc cc tm ca mi cha.* m b tng: c dng khi c s chp thun ca T vn gim st, bm v vn hnh lin tc sao cho khng c c bong bng cha khng kh bn trong. Trong v sau khi b tng phi m k c mt khi cht ng u. Phi m t pha trong b tng m ra. Cho php m pha ngoi i vi mt trn ca kt cu DL hay ch c bit khc. Trc khi thi cng cc my m phi c T vn kim tra, chp nhn, d tr phng khi thit b trc trc. My m phi hot ng thi gian v cng m bo b tngc m k, nhng khng c hot ng qu mc lm cho b tng b phn tn. bt k thi im no xut hin va lng th khng c m na. Trnh khng c m tip xc vi ct thp, hay tip xc trc tip vi b tng ng kt.* Thi cng cc mi ni: Nu trn bn v khng ghi chi tit th s b tng cho cc mi theo ch dn ca T vn gim st. Ti cc mi ni s dng nhng cht ct hoc ct thp vt lin kt hai on vi nhau, nu khng c cht ct hoc ct thp vt th phi to nhm b mt b tng. Cc lp b mt c c ra sch, trc tin phi qut ln chng mt lp va xi mng ct theo t l 1:2 hoc va xi mng khng v trc khi lp va bt u ng kt mt lp b tng mi s c theo . Phi b tng lin tc t mi ni ny sang mi ni khc. Ngay khi ngng b tng phi co b tt c va bm trn thp chu lc v trn cc thanh ca cp pha. Cc mnh va kh v bi khng c bm vo b tng cha ng kt.* Bo dng b tng: Ngay sau khi b tng phi bo v b tng, khng b nhng tc ng c hi ca thi tit v khng c b tng kh cng. B tng phi c bo dng trong trng thi c m v nhit cn thit ng rn v ngn nga cc nh hng c hi trong qu trnh ng rn ca b tng. Cch bo dng, thi gian tun theo quy trnh bo dng m thc hin theo TCVN5592-1991 B tng nng - yu cu bo dng t nhin. Thng thng dng phng php gi nguyn cp pha ti ch v che y kn b mt b tng cha thnh hnh bng cc vt liu nh rm, r,bao ti, ct hay vt liu thm ht nc v vt liu ny phi c gi lun lun m. Trn cc mt c khun, nu g khun ra trc khi kt thc thi gian bo dng th phi tip tc bo dng cc mt cha hnh thnh (cha c khun). Ch c cht ti sm: khi c s chp thun ca TVGS v TVGS cn c vo cng b tng yu cu lc cht ti.* Th nghim : Mi ln ly mu th nghim s ly 2 t hp mu th nghim v cng nn 3, 7, 28 ngy. Mi t hp mu c hnh lp phng kch thc 15x15x15cm. Gi tr trung bnh ca cng nn ca 3 mu th s l cng nn ti a ca c b mu th. i vi kt cu chnh ca cng trnh mi ln b tng phi ly mu mt ln, mi ln ti thiu 3 t hp. Nh thu cn ly thm cc mu th quyt nh thi im c th tho gi cp pha, thi im c th to ng sut trc. Cc mu th ny c bo dng trong iu kin nh bo dng kt cu va thi cng xong ti hin trng. Trong vic xc nh cng nn trung bnh ca bt k mu th no, khng mt mu c bit no c tr s nh hn 95% ca cng b tng thit k ( n), nu khng t c th yu cu ly li cc mu th kt cu ra kim tra. Nh thu s phi chu hon ton kinh ph kim tra ny. Nu kt qu th nghim p ng c mi yu cu quy nh v c cp c thm quyn ph duyt th kt cu hay phn s c nghim thu.2. Yu cu ct thp thng:a) Yu cu v vt liu: S dng thp trn trn AI, fy = 2400kg/cm2. S dng thp c g AII, fy = 3000kg/cm2, AIII, fy = 4000kg/cm2. Dy buc: phi l loi dy thp mu en mm v c cht lng cao, ng knh khong 1,6mm. Phi c giy chng nhn ca nh sn xut (Nc, nh my, ch tiu c l ca l thp). Bo v: Trong nh kho ct thp phi c xp trn b cch. Khi em ra s dng, ct thp khng c b nt, khng b p mng bt i, hoc bi, hoen g, b r, c dnh sn, du m hay b cc tp liu ngoi lai khc bm vo. Ct thp han r tit din gim yu qu 5% phi loi b.b) Yu cu thi cng ct thp: Ct thp s c un ngui theo hnh dng ghi trong bn v. Cc thanh thp c mt phn trong b tng th khng c un hin trng, tr trng hp c hng dn trong bn v hay c php c bit. ng knh ca ch un nh hng dn trong bn v (Nu khng c ghi th theo quy phm hin hnh). Tt c cc vic ct v un thp phi cho nhng cng nhn c nng lc lm. t, , chng v buc ct thp: Phi t ct thp chnh xc theo n thit k, phi c gi cht bng nhng gi (hay thanh chng) c chp thun. Cc thanh thp phi c buc hoc hn vi nhau tht chc chn theo ng quy trnh v ch dn k thut, khng c php t hay lun ct thp vo trong b tng sau khi b tng vo khun. Cc vin b tng k ct thp theo yu cu m bo ct thp c t ng v tr. Con chn phi l b tng cng mc vi b tng ca cu kin, v phi buc n vo vi ct thp. Trc khi b tng phi c s ng ca TVGS sau khi kim tra nghim thu ct thp. Ch cc thanh thp giao nhau s c buc hoc hn vi nhau. Ch c thay th ct thp khc nu c cng kch c, cht lng cao hn quy nh v c s ng ca TVGS. Ct thp c ct bng phng php c hc. Khi un ct thp phi c un quanh mt li vi tc chm sao cho m bo bn knh un cong u v theo ng bn v. i vi ct thp trn trn ng knh ca li dng un ct thp phi ly t nht bng 5 ln ng knh ct thp , tr trng hp cc khung cc t ai ( m ng knh ln hn hay bng 16mm th ly ng knh li un t nht bng 3 ln ng knh ct thp ). i vi ct thp c g ( c bm dnh cao vi b tng) ng knh ca li ( tnh bng mm) un ct thp phi khng nh hn cc tr s cho trong bng sau:ng knh danh nh ct thp (mm)45681012141620253240

Ct ai v khung20303040506090100Khng p dng

Mc cu neo40507070100100150150200250320400

Ch unKhng p dng15020020025030040500500

- i vi thp d ng lc v neo thp phi Nh thu phi s dng loi thp ca nhng hng sn xut t tiu chun quc t v phi c chng ch ca ngi sn xut v trc kh a vo s dng phi c s ng ca TVGS v ca ch u t th nh thu mi c php s dng. Ni ct thp:+) Mi ni trong ct thp nn c chiu di chng ln nhau l 25 ln ng knh thanh thp. Lin kt hn phi m bo cht lng mi hn theo yu cu thit k phng php v cng ngh hn phi tun theo tiu chun 20TCN71-77.+) Ch dn hn ct thp v chi tit t sn trong kt cu b tng ct thp. Hn i u theo phng php no cng phi tun theo Tiu chun 20TCN 72-77. Khi ch to khung ct thp v li ct thp : i vi thp trn trn hn tt c cc im giao nhau, thp c g hn tt c cc im giao nhau hai hng chu vi pha ngoi, cc im gia cch 1 hn mt theo th t xen k. i vi khung ct thp dm hn tt c cc im giao nhau.+) Cc mi hn phi m bo cc yu cu sau: B mt nhn, khng chy, khng t qung, khng thu hp cc b v khng c bt, chiu cao v chiu di ng hn m bo theo quy trnh. Cc mi ni buc cn buc t nht 3 v tr (u, gia, cui).3.Cng ko d ng lc Ch c php cng ko DL khi b tng t cng ti thiu l 90% cng thit k. Tt c cc thit b neo, ko cng sau phi kh nng gi thp d ng lc chc chn. C ng sut khng nh hn 95% cng chu ko ti a ca thp DL. S dch chuyn ca chu neo khi ng neo ti a khng qu 6mm. Cc l lun cp u phi bng thp m km c g, mi ni gia cc ng phi m bo kn va khng lt vo c v khng b bin dng khi b tng. Va phun lp lng ng lun cp gm xi mng, nc v ph gia chng co ngt cng vi cht lm chm ninh kt. Thnh phn cp phi ca va phun khi thit k xong phi trnh TVGS v c TVGS chp thun mi c php thi cng. Khng c s dng bt k loi ph gia no c cha clorua hoc Nitrat. Vic to DL c thc hin bng kch thu lc, nng lc ca kch phi ln hn lc ko ti thiu l 20%, trc khi cng ko tt c cc thit b to DL (Kch, ng h o p sut ) phi c hiu chnh. Khi b tng t cng yu cu phi tin hnh tho d ton b vn khun thnh mi c cng ko. Ch c tho tm y ca dm hoc nhc dm ra khi b khi qua thi gian ti thiu l 48gi sau khi phun va vo cc ng lun cp v ct ct thp d ng lc. Sn o ( hoc b dm ) phi c thit k v lp t sao cho khi cng ko d ng lc dm BTCT khng b nng ln hoc ngn li. Qu trnh cng ko d ng lc phi c thc hin sao cho trong mi trng hp kim sot c lc cng v dn di ca cp, phi duy tr vic ghi chp v p lc cng ko, dn di, ti liu ny phi c TVGS kim tra ti hin trng. Thp d ng lc phi c dnh kt vo b tng thng qua va phun khng co ngt c phun vo ng to l cha cp cng cao. Tt c cc ng phi sch khng ln cc tp cht gy nh hng n s dnh kt ca va (Du, m, bi bn.). Tt c cc va phun phi c sng qua mt sng c mt sng ti a l 1.2mm trc khi a vo my phun, ch c tho m cc van khi va ninh kt.

Chng IV : Bin php thi cng nhp dn Quy trnh thi cng(Thi cng lao dm cc tr M0 T1; T1 T2; T5 T6; T6 M7)T chc thi cng dm T bao gm cc hng mc cng vic nh sau:1. B tr mt bng cng trng.2. Thit b phc v thi cng. 3. Chi tit b c dm.4. Vn khun dm.5. Sn xut v lp t ct thp.6. b tng dm.7. Cng ko v cc thit b cng ko.8. Qu trnh cng ko cp DL.9. Ct cp, to d ng lc cho btng dm.10. Tho d vn khun.11. Cu tn trang v lu gi dm.12. Kim tra cht lng dm PCI.13. Cng tc lao lp dm.I. Ch to dm T1. B tr mt bng phc v thi cng cng trnhCc lp t nh sau : + Lp 1 : Cui a khong mu xm,bo ha + Lp 2 : St mu vng na cng. + Lp 3 : St ln cui mu xm vng + Lp 4 : Sa ip mu xm xi mng,xm nu,xm en xan kp cc lp sa thch ht nh phong ha nng, cng cp III. + Lp 5: vi mu xm trng,phong ha dng dm,vn c ch thnh st cng cp IV-VI. + Lp 6: vi mu xm trng,phong ha nt n t, cng cp VII. Da vo a hnh ca cu v cc lp a cht nh trn ta tin hnh b tr mt bng bi c dm nh sau : c b tr ti u cu,tim dc ca bi song song vi tim dc ca cu tin li trong qu trnh lao lp kt cu nhp sau ny Cc mt bng phc v thi cng dm T c b tr nh sau: a) Trm trn b tng Din tch : 8 x 8=16 m2b) Kho thp Din tch : 18 x 4=72 m2c) Mt bng lp t lng thp. Din tch: 35 4m = 140m2 d) Khu vc gia cng thp Din tch: 35 2m = 70m2 e) Mt bng b c dm. Din tch: 35 5m = 175m2f) Mt bng cha vn khun c dm. Din tch: 35 3m = 105m2g) Mt bng ng xe vn chuyn btng. Din tch: 40 7 = 280m2 h) Mt bng cc cng trnh phc v thi cng khc: Bao gm cc trm cung cp nc bo dng v in chiu sng phc v thi cng. Mt bng ny c b tr tp trung xung quanh b c.i) Bi cha dm : Bi cha dm phi cha c ti thiu 6 dm cho mt nhp cu dn. Mi dm c kch thc cnh l 0,85m nn:Din tch: 35 6x2 = 420 m2. Tng din tch mt bng thi cng dm T khong: 1278 m2.2. Cc s liu phc v c dmDm cu c thit k l dm ch T chiu di dm l 33mMt ct ngang dm cu

Btng : s dng btng cng cao M400 Ct thp : Ct thp cng cao : Mi dm gm 4 b cp DL, mi b gm 12 tao 12.7 (mm) theo tiu chun ASTM A416 grade 270 Ct thp thng : thp theo TCVN 1651 853. Cng tc vn khun v ct thp dm di 35 (m)3.1.Cng tc vn khun3.1.1.B c dmB c dm c thi cng theo thit k gm cc lp sau :+ t nn m cht K =0.95+ dm m cht dy 10 (cm)+ tm btng kch thc 200x200x25 (cm) 2 u dm v gia dmyu cu b c phi bng phng v chu c cc lc tc dng khi c dm. Hai u b c phi chu ng c ti trng bn thn ca dm ,c truyn xung do hai u dm t xung khi cng ko ct thp ST3.1.2.Lp rp vn khun y Vn khun y c gia cng bng thp bn d=8mm v thp hnh U200 Ti khe ni cc tm t rong cao su dy 4mm. Vn khun y c lin kt chc chn vi b c dm bng bulng v hn lin kt vo cc thp ch b c dm. Yu cu : Mt vn khun khng b cong vnh. chnh bng phng ta dng cc con nm bng g v st. Ring 2 tm vn khun y u dm phi lin kt sao cho chc chn nhng li d tho d khi to b u dm khi cng cp ST. Ti ch ni ca 2 tm vn khun y ta dng matit trt khe.3.1.3.Vn khun dm. Dng loi vn khun thp chuyn c dm I cao 1.5m di l 33m. Trn thnh pha ngoi vn khun c gn sn cc m rung,khong cch trung bnh gia cc m l 1m/ci c b tr so le nhau 2 bn thnh vn khun,cc m rung c bt bulng cht ch vi vn khun thnh dm theo thit k. H thng m di c b tr trn mt dm vi 4 m di 30 - 50mm3.1.4.Lp dng vn khun u dm v thnh dm. Cc tm vn khun phi c ty sch g v btng c,sau c qut lp du c th tho d vn khun c d dng. Vn khun u dm trc khi lp dng ta phi lin kt thn neo vo vn khun u dm bng cc bulng tu theo cu to ca thn neo. L bm va ca thn neo phi hng ln trn. lp c vn khun dm ta phi lp vn khun u dm trc sau lp 2 tm vn khun thnh dm i xng nhau t u dm n cui dm,tm vn khun u dm bn kia c lp sau. Gia cc tm vn khun ta phi dng rong m cao su.3.2.Cng tc ct thp.3.2.1.Ct thp cu to.Dng loi 10 - 16 nhm AII .a. Lp dng ct thp. Ct thp phi c gia cng v lp t theo ng bn v thit k,cc mi lin kt c buc chc chn v c hn nh v mt s im phng xy ra bin hnh khung ct thp khi vn chuyn cu lp. Ct thp trc khi a vo buc phi c v sinh sch s, khong cch gia ct thp v vn khun (b dy lp btng bo v) c chn bng cc con k c lm bng va btng c mc cng mc vi btng dm.b. Li nh v ,ng gen. Cc li ny c gia cng v lp t ng v tr nh trong h s thit k,nu sai s nh hng n vng ca dm khi ko cng ct thp ST,nh hng n s lm vic ca dm.c. Lp t ng gen. ng gen c lp t sau khi ct thp bu dm,sn dm,li nh v c buc xong. ng gen c ni chiu di mi c lun hoc lun ht tng on ta mi ni ng tip. on ng ni mng sng di 30 cm,ti ch mng sng dng bng dnh qun cht phng va btng chy vo trong lng ng trong qu trnh btng.d. Bo qun ct thp,ng gen. Khi buc xong ct thp cui ngy ta phi dng vi bt che kn trnh ma v sng m c th lm han g ct thp.3.3.Cng tc btng.3.3.1.Cng tc btng. Btng dm M400. cng btng 28 ngy tui vi mu nn hnh lp phng 150x150x150cm phi bo m >400 Kg/cm2 st ca btng trc khi l 8 10cm. S dng loi ph gia sika.3.3.2.Cng tc thi cng btng. Btng c sn xut ti trm trn btng c cng sut 25m3 /h v c vn chuyn n cng trng bng xe chuyn dng. btng bng vi phun btng. Chia dm lm 4 on btng,trong tng on trnh t nh sau: + Trc tin ri u btng cho phn bu dm,lp 2 v 3 cho phn thn dm,lp 4 cho phn cnh dm. Btng n u th cho m rung hot ng ngay n . m di khng c t st vo v tr ng gen trnh kh nng ng gen b m di chc thng. Chiu di lp btng sau khng c di hn lp btng trc m phi ngn hn to thnh hnh vt so vi mt phng thng ng ct ngang dm. Thi gian btng cho 1 phin dm khng c 70cm.3.4.5.Lp vng neo v cc nt neo. Khi cc b cp c lun y trong lng ng gen ta tin hnh lp cc vng neo trc,lp cc nt neo sau. Khi lp cc si cp gia phi cho vo l gia vng neo,vng neo phi st vi thn neo,sau lp cc nt neo.3.5.Cng ko ct thp ST.3.5.1.Cng tc chun b. Khi btng dm t t 8085% cng thit k th tin hnh ko cng. hai u c b tr cc tm bng ghi cc cp lc ko cng v tr s c trn ng h p lc tng ng vi cc cp ko cng. B tr mi u dm mt gi treo kch bng palng xch v cc t vt chng phng h hai bn thnh u dm. Trc khi ko cng phi th li ton b h thng kch.3.5.2.Lp cp vo kch. Hnh trnh ca kch lc ny phi v tr xut pht. K thut vin phi kim tra c th nu khng th khi kch ht hnh trnh m lc ko vn cha t. Khi lp kch th cc si gia phi lp gia. Dng tay y kch st vo vng neo.** Trnh t ko cng ct thp ST ** Dm T ca kt cu nhp cu qu cao l dm btctst c cng ko ngay ti bi cha dm sau khi tho d vn khun,vi 4 b cp dl mi b gm 12 tao, mi tao gm 7 si thp ng knh danh nh l 12.7mm. Trnh t cng ko cc b theo ng h s thit kBc 1. M my ko vi lc bng 0.1Pk ,y ch l bc so dy. Khi lc ko t 0.1Pk th ta th kch v cho hi v 0.Bc 2. M my ko vi lc bng 0.1Pk khi t th tt my,o dn di ca cp v thng bo tr s dn di.Bc 3. M my ko vi lc bng 0.2Pk khi t th tt my, o dn di ca thp v thng bo tr s dn di.Bc 4. M my ko vi lc bng 0.4Pk khi t th tt my,o dn di ca cp v thng bo tr s dn di.

Bc 5. M my ko vi lc bng 0.6Pk khi t th tt my,o dn di ca cp v thng bo tr s dn di.Bc 6. M my ko vi lc bng 0.8Pk khi t th tt my,o dn di ca cp v thng bo tr s dn di.Bc 7. M my ko vi lc bng 1.05Pk khi t th tt my,o dn di ca cp v thng bo tr s dn di. Duy tr tr s p lc 1.05Pk trong vng 5 pht,a kch v 0.2Pk sau ng neo h kch v 0 o lng cp tt neo u kch.Ghi ch Pk l lc ko cng thit k. Tho kch v hon thnh vic cng ko mt b cp. Cc b cp khc cng c tin hnh cng ko tng t. Trong cc bc t bc 2 n bc 6 khi tng lc kch ca 2 kch th duy tr lc o dn di ca cp. Khi kt thc vic cng cp th tin hnh o vng ca dm. Cch tin hnh o vng ca dm nh sau: t my thu bnh ti im gia cch tim dc dm 5m,ngm my nh du vo 3 v tr gia v hai u dm,ti cc v tr dn 3 bng giy k li cn c vo ta xc nh c gi tr ca vng gia dm v ln ca b 2 u dm. vng ca dm = vng gia + ln uTB ln uTB = (ln u 1 + ln u 2)/2 o dn di ca cp hai u kch ta lm nh sau: ta dng thc nha di 30cm,sau khi ko xong mt cp lc ta o c phn cn li ca xilanh kch. dn di chnh l tr s hnh trnh kch tr i s o phn cn li ca xilanh kch. Mi u ta b tr mt ngi o,tr s dn di ca cp l tng ca 2 tr s dn di 2 u kch cng li ca mi cp lc ko.3.6.Cng tc an ton. Nghim cm khng cho ngi i li v ng pha u dm khi cng ko phng cp b t gy tai nn.3.7.Bm va vo trong lng ng gen.3.7.1.Cng tc chun b. Ct cp tha 2 u neo: Cp tha 2 u neo phi c ct b,vt ct cch mt vng neo l 5cm,dng my ct ct khng dng hn in hoc hn hi ct. Bt kn u neo gi cho p lc va khng b thot ra ngoi trong khi bm va,phi bt kn u neo bng va ximng ct c t l pha trn nh btng dm,sau 48h bt u neo ta mi tin hnh bm va. Chun b va bm. Va ximng bao gm ximng Porland PC40 (khng vn cc),nc c pha trn vi t lN/X = 0.35 0.4,dng ph gia trng n INTRAPLAST v ph gia ho do R4 ca hng SIKA. linh ng ca va khng ln hn 20 giy,sau 30 pht khng ln hn 40 giy. Va c trn theo trnh t: nc vo my trn sau cho ximng vo trn u tip cho ph gia vo. Thi gian bt u trn cho n khi bm khng di 4 pht. My bm va dng loi OVM ca Trung Quc,p sut bm 35Kg/cm2 ,lu lng 36l/pht. Trc khi bm phi dng vi bm nc c p lc v my hi p thi sch l ng gen.3.7.2.Trnh t bm va. Lp van vo l bm va,lp 2 van vo 2 thn neo ca cng mt b cp,van u ni vi my bm va van cn li l van ca ra,2 van c trng thi m. Bm va: Sau khi ni ng dn vi van ca vo ta tin hnh bm va lin tc. Khi thy va chy van ca ra m lng va chim ht tit din ca van th ng li,xem ng h p lc nu thy p sut t 67 Kg/cm2 th tt my bm, duy tr p lc trong vng 2 pht sau kho van ca vo v kt thc vic bm va. Sau 4h khi bm xong th ta tin hnh tho cc van ra. Khun mu c dng loi 7x7x7 cm,c 2 t mu cho mt dm.3.8. btng bt u. Btng bt u dm phi lin kt tht tt vi btng thn dm. Trc khi bt u dm phi to nhm tht k cc u dm. Cng tc to nhm ny phi tin hnh sau khi bm va 24h,tuyt i khng c va chm vo cc si thp phng tt neo. Dng loi btng c cng mc nh btng dm vo l bt u dm. Dng m di v que thp kt hp vi v g g nh ngoi vn khun cho btng c cht Btng bt u dm phi c bo dng tht tt,trnh bt co ngt phng btng u dm lin kt khng tt vi btng thn dm. Cng btng u dm khi tho vn khun ti thiu phi t 100Kg/cm23.9.Kim tra dm T Sau khi hon thnh vic ch to dm ta tin hnh kim tra tng th v chi tit dm ln cui chun b cho vic lao lp.II Lao lp dm T cho kt cu nhp dn Do c im ca a cht xy dng cu v kt cu nhp dn nm trn bi sng do vy ta xut phng n lao lp dm nh sau :Thi cng ng cng tc dc hai bn cu.Lp dng ng ray cho xe gong ch dm ng ray ny song song vi bi tp kt dm T.Lp dng ng ray cho gi long mn, a gi long mn vo v tr kho cht khng cho di chuyn.Dng xe gong vn chuyn dm vo v tr.Gi long mn nhc dm ra khi xe gong v cu.Lao dm v sng ngang dm vo v tr thit k.H dm xung nh tr, c nh dm v tin hnh lao cc dm tip theo.Thi cng phn bn mt cu ti ch cho h dm T.III Chn cu long mn Cu long mn l thit b dng nng h dm Tra khi b c trong qu trnh c dm v thi cng lao lp nhp dn. Theo khi lng tnh ton ln nht tnh cho mi phin dm l khong 35 m3 btng. Tng khi lng ca mi phin khong 87.5T Btng + 7T Thp thng + 2,5T Thp cng cao. Nh vy khi lng nng ca cu long mn l 97T Theo iu kin hot ng ca cc thit b nng ni chung l phi c sc nng ln hn 1,2 ln ti trng nng cn thit. Ngha l b gi cu long mn phi c sc nng ln hn 120T.Vy: Chn 02 cu long mn mi cu long mn c sc nng 60T Cu long mn l thit b c kt cu l khung siu tnh, khng c lin kt ngang trong lng long mn. Lin kt chn gi v x nh dng 4 cht 90 trn kt hp vi 4 bulng 88 lp pha di. Lin kt chn gi vi dm chn dng 4 cht 90. Dm x nh di 12m( khi s dng ch to dm) v 15m( Khi s dng lao lp dm nhp dn), s dng cc dm [ 700 cnh rng 300. C hn tng cng. Ct chn gi dng H400, x chn dng 2 [ 300. Kt cu nng dng ti 6T s dng b palng c bi xut 11 v c t trn xe gong c chiu rng l 1,5m. Chn gi c c cu di chuyn v th n c th t di chuyn trn ray mt cch r rng. ghi ch:(1) . Ray cu long mn.(2) . Ray vn chuyn dm T(3) . H ti ko.(4) . Xe gong 1.5m.(5) . Ti tang ko.(6) . Ti 6T.(7) . Puli chuyn hng.(8) . Ct H400.(9),(11) . 4 cht bulng 88.(12) . Dm T.(13) . C cu di chuyn. Hnh : Cu to cu long mniV Kim tra iu kin lm vic n nh ca cu long mn Cu long mn thc cht l cng trc v th vic kim tra n nh ca n c tnh nh cng trc: Cu c kim tra theo c hai phng, phng dc ray v phng vung gc vi ray vi ti trng nng ln nht v c tnh ti ti trng qun tnh.+)Theo phng vung gc vi ray(xt vi t hp lc)H s n nh ca cu trong trng hp ny:

K1 = = > 1,4Trong : GM - Trng lng ca cn trc.GT - Trng lng ca xe con.Q - Trng lng ca vt nng.* ) Fk : Lc cn gi tc dng ln cng (theo quy nh cu long mn ch lm vic ti gi cp V) Fk = q.n.c..A Trong : + q: p lc gi ln nht trng tri lm vic, y ly gi ln nht l cp V q = 28 N/m2. + c: H s kh ng hc c = 1 + n: H s k n s tng p lc gi theo chiu cao n = 1 + : H s ng lc hc k n c tnh xung ng ca ti trng gi = 1,3. + A: Din tch chn gi ca kt cu . *) Fv : Lc cn gi tc dng ln vt nng c quy v im treo: Fv = q.n.c..ATrong : + q: p lc gi ln nht trng tri lm vic, y ly gi ln nht l cp V q = 28 N/m2. + c: H s kh ng hc c = 1 + n: H s k n s tng p lc gi theo chiu cao n = 1 + : H s ng lc hc k n c tnh xung ng ca ti trng gi = 1,25. + A: Din tch chn gi ca kt cu . *) Pqt1: Lc qun tnh khi phanh c cu di chuyn xe con.

Pqt1 = m.a = m.

12000GMFKG + QFqt1FVa b c L Hnh: Ti trng tc dng ln cuVy ta hon ton tnh c K1> 1,4 or < 1,4.Suy ra cng trc n nh theo phng vung gc vi ray hay khng +) Theo phng dc vi ray Khi nng hng th cu long mn hon ton ng yn khng di chuyn dc ray c nn khng sinh ra lc qun tnh.

K2 = F: Lc cn gi tc dng ln cng trc theo phng dc ray.Trong : + Cc h s tng t nh trn + A: Din tch chn gi ca kt cu . Suy ra ta tnh c F .Thay s vo ta tnh c K2 > 1,15

Khi cu long mn di chuyn dc ray khi khng ti v v tr no hoc khi n b chn bi gim chn cui ng ray

4400108007004 cht 902000Hnh: Ti trng tc dng ln cu

Pqt = m.a = m. (T)

K2 = > 1,15 or < 1,15.Suy ra cu long mn n nh theo phng dc trc hay khng. Kim tra hai iu kin trn xem cu long mn c tho mn iu kin lm vic hay khng sau a ra kt lun phc v thit k v thi cng .

Gio vin hng dn:Nguyn bnh HTrang 1 Sinh vin thc hin:Nhm 19