to chuc tc chuong 12

7/26/2019 To Chuc TC Chuong 12

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NI DUNG1.Cc vn chung2.Cc phng php t chc thi cng3.Cc phng php thit k t chc thi cng4.Thit k t chc thi cng ng t

5.Cung cp vt t vt chc vn chuyn6.Qun l KT thi cng - kim tra - nghim thu

Chng 1: Cc vn chungTit 1.1. Khi nim v mn hc

1. Khi nim :T chc thi cng ng t (TC2) l vic tin hnh hng loi cc bin php tng hpnhm b tr cc ngun lc xy dng cn thit tin hnh xy dng cc hng mc catuyn ng theo ng n thit k.

Mn hc "T chc thi cng ng t" l mt mn hc kinh t-k thut nhmnghin cu vic s dng hp l cc ngun lc xy dng thc hin cc hng mc cngtc; ng thi xc nh r th t s dng v quan h tng h gia cc ngun lc ytrong sut thi gian thi cng, hon thnh tuyn ng ng thi hn, vi cht lngtt, gi thnh r.2. Mc ch nghin cu ca mn hc TCTC :* Nghin cu cc vn c th v cng tc t chc cc qu trnh :

-cung cp nguyn vt liu;

-vnchuyn;-xy lp cc hng mc cng trnh trong cc iu kin rt khc nhau v: a

hnh,a cht, a mo, kh hu, thy vn...


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* Nghin cu mi quan h gia cc yu t:-tin thi cng;- nng sut lao ng;-cht lng;-gi thnh cng trnh

*Nghin cu p dng kp thi cc thnh tu khoa hc cng ngh tin tin; cc sng kinci tin k thut trong cc hot ng ca cng trng nhm m bo thc hin c

phng chm : "Nhanh -Nhiu - Tt -R"3. Cc lnh vc c lin quan :

hc tt mn hc TCTC, cn phi hiu bit thu o kin thc v cc lnh vc :-K thut thi cng cc hng mc cng trnh;-Quy trnh, quy phm thi cng;-Cc nh mc s dng my mc, nhn lc, vt liu trong xy dng;-D ton trong xy dng;-Cc ch trng chnh sch ca Nh nc, ca tng a phng.

4. Phng php nghin cu :TCTC l mn hc kinh t-k thut nn phi c phng php nghin cu ng n :

-Xem xt cc vn phi o bo tnhtng qut, phi thy c mi lin hca mn hc vi cc mn hc khc.

-Nghin cu cc gii php t chc phi m bo tnh khoa hc v thc t; phithy c u, nhc im vphm vi s dng ca tng gii php.5. Ti liu tham kho:[1]. Dng Hc Hi, Nguyn Quang Chiu. T chc thi cng ng t. NXB GTVT.H Ni 2000.[2]. B Giao thng vn ti. Tuyn tp Tiu chun k thut thi cng nghim thu nn mtng t. NXB GTVT. H Ni 2005.[3]. B Giao thng vn ti. Tuyn tp Tiu chun k thut thicng nghim thu cu cng.

NXB GTVT. H Ni 2005.[4]. L Vn Kim, Ng Quang Tng. Qun l d n bng s mng. NXB i hcQuc gia thnh ph H Ch Minh. T.P HCM 2001.[5]. Trnh Quc Thng. Cc phng php s mng trong xy dng. NXB Xy dng.H Ni 1998.[6]. B Xy dng. nh mc D ton Xy dng cng trnh. Ban hnh theo Quyt nh s24/2005/Q-BXD ngy 29 thng 7 nm 2005.

Tit 1.2. Phn loi cng tc xy dngngTheo ngha, phng tin sn xut s dng v tnh cht t chc, cc cng tcXD c phn thnh 3 nhm :

-Cng tc chun b;-Cng tc vn chuyn;-Cng tc xy lp.

1. Cng tc chun b :Bao gm cc cng tc chun b cc loi vt liu xy dng, cc loi bn thnh

phm, cc loi cu kin c sn dng trong xy dng ng. Cng tc chun b thngdo cc x nghip phc v xy dng ng ca cc n v thi cng m nhn nh : cc mkhai thc v gia cng vt liu lm ng, cc c s gia cng nha ng v ch to nhtng, cc trm trn BTN - BTXM, cc x nghip ch to cu kin BTXM v BTXMCT.


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2. Cng tc vn chuyn:L vic iu ng cc loi vt liu xy dng, bn thnh phm v cu kin c sn

t ni khai thc, gia cng, ch to n ni s dng. Bao gm :-Vn chuyn vt liu t m n tuyn.-Vn chuyn vt liu t m n x nghip ph.-Vn chuyn cc bn thnh phm v cu kin c sn t cc x nghip ph n

tuyn.3. Cng tc xy lp :

L cc cng tc trc tip hon thnh cc hng mc xy lp nh : cng, k, nnng, mt ng . . . Cng tc ny li c chia thnh 2 loi :

-Cng tc tp trung : l cc cng tc c khi lng c bit ln, k thut thi cngphc tp, s dng cc thit b c chng v hu nh khng lp li cc on ngkhc.

-Cng tc dc tuyn : c khi lng phn b tng i ng u trn mt n vchiu di tuyn, c k thut thi cng lp i lp li mt cch chu k. m bo honthnh cng trnh ng tin , bao gi cng phi tp trung cc ngun lc thi cngnhm hon thnh sm cc hng mc cng tc tp trung trc khi cng tc dc tuyn trinkhai n.

Tit 1.3. cim ca cng tc xy dng ngV mt t chc cng tc xy dng ng c 4 c im:-Din thi cng hp v ko di.-Ni lm vic ca n v thi cng thng xuyn thay i.-Khi lng cng tc phn b khng u trn tuyn.-Chu nh hng trc tipcc iu kin kh hu, thi tit.

1. Din thi cng hp v ko di :Din thi cng ( phm vi thi cng ) l chiu rng di t m n v thi cng c

php o, t; b tr cc phng tin thi cng, tp kt vt liu ... thng ch rng vimt n vi chc mt song li ko di vi km n hng ngn km. iu ny gy kh khncho cng tc kim tra, iu hnh sn xut; cho vic b tr lc lng thi cng; hn chmy mc v nhn lc pht huy nng sut.2. Ni lm vic ca n v thi cng thngxuyn thay i :

Khc vi cc dy chuyn sn xut cng nghip : nguyn vt liu di chuyn qua cckhu gia cng thnh sn phm; cc tuyn ng phi thi cng nm c nh,n v thi cng phi di chuyn thng xuyn trn tuyn hon thnh ng cc khi

lng cng tc ca mnh. iu ny gy kh khn cho vic b tr ch n cho cng nhnv cn b k thut, cho vic b tr cc kho tng, sa cha xe my.3.Khi lng cng tc phn b khng u trn tuyn :

Khi lng thi cng cc on ng khc nhau rt khc nhau, nhiu k thut thicng cng c s khc bit gia cc on, gy kh khn cho vic t chc thi cng dychuyn; cho cng tc t chc, iu hnh sn xut.4.Chu nh hng trc tip cc iu kin kh hu, thi tit :

i a s cc hng mc cng tc trong xy dng ng u phi trin khai v tinhnh ngoi tri; v th cc yu t kh hu, thi tit u c nh hng trc tip n qutrnh thi cng. iu kin thi tit khng thun li c th ph v tin thi cng d

kin; lm gim cht lng cng trnh; lm tng cc chi ph xy dng do my mc vnhn lc phi lm vic gin on hoc do cc hng mc cng tc ang trin khai b hhng.


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Tit 1.4. Cc nguyn tc c bnDo cc c im nu tit 1.3, nn khi tin hnh TCTC ng t cn thc hin ttcc nguyn tc :1. m bo tnh chuyn mn ha cao :

Phn cng tc xy lp lm nhiu cng vic khc nhau theo: tnh cht cng vic,

phngphp thi cng, phng tin s dng vbin php t chc c th. Cc cng vicny c thc hin bi cc i thi cng chuyn nghip, to iu kin tt nng caonng sut, m bo cht lng, rt ngn c thi gian thi cng.2. m bo tnh cn i:

T chc cc n v chuyn nghip phi m bo tnh cn i gia my mc - thitb nhn lc, gia my chnh - my ph. Phi m bo tnh cn i gia khi lngthc hin v nng lc cng tc ca cc i chuyn nghip. Gia cc i chuyn nghip

phi m bo tnh cn i c th phi hp nhp nhng.3. Hon thnh sm cc hng mc cng tc tp trung :

Phi xc nh r cc hng mc cng tc c tnh cht tp trung trn tuyn.

Tp trung nhn vt lc hon thnh sm cc hng mc cng tc tp trung, trngim.4. Hn ch nh hng xu ca cc iu kin kh hu, thi tit bt li :

Bng cch : chn ma thi cng c li; c gii ha ng b cc khu thi cng; sdng ngy cng nhiu cc loi BTP v CKS.5. T chc tt khu cung cp vt t, vn chuyn trong sut qu trnh thi cng.6. Thng xuyn kim tra tin trong qu trnh thi cng c cc iu chnhnhanh chng, kp thi, hp l.

Chng 2: Cc phng php t chc thi cngTrong XD hin s dng cc PP TC2:

-Phng php t chc thi cng tun t.-Phng php t chc thi cng song song.-Phng php t chc thi cng dy chuyn.-Phng php t chc thi cng hn hp.Mi PPTC2khc nhau s gii quyt vn t chc lc lng thi cng, vn phi

hp cc khu thi cng v khng gian, thi gian theo cc cch khc nhau; do yu cuv khu cung ng vt t, t chc vn chuyn, trnh ta cc on ng vo s dngcng rt khc nhau.

Cng mt i tng thi cng, nu chn PPTC

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khc nhau s dn ti cc phng nthit k t chc thi cng hon ton khc nhau. Mun TC2tt, t hiu qu cao phi tinhnh thit k t chc thi cng trnc s mt PP TC2tin tin v thch hp vi cc iukin c th ca cng trnh.

Tit 2.1. Phng php t chc thi cng tun t.1. Khi nim :

T chc thi cng theo phng php tun t, (P2TC2T2) l vic chia tuyn ng thicng thnh tng on c khi lng thi cng xp x nhau; mt n v thi cng s ln lthon thnh cc hng mc cng tc trong tng on, t on ny n on kia

theo mt th t xc nh.


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2. c im :-Tuyn ng c chia thnh nhiu on ng c khi lng cng tctng

ng.-Mt n v thi cng thc hin ton b cc cng tc trong tng on, ht on ny

li di chuyn n on khc.-Cc ng nm ngang biu th thi hn hon thnh cc hng mc cng tc, cc

on ng; ng nm ngang trn cng biu th thi hn hon thnh tuyn ng.3. u, nhc im :

3.1. u im :Do thi cng tng on, hon thnh tng on nn :-Khng yu cu tp trung nhiu my mc, thit b, nhn lc; gim p lc cho khu

cung cp.-Yu cu lng vn lu ng nh.-D iu hnh, qun l, d kim tra.-t chu nh hng xu ca cc iu kin kh hu thi tit.

3.3. Nhc im :-Thi gian thi cng b ko di.-My mc, nhn lc lm vic gin on do phi ch i nhau; lm tng chi ph s

dng my mc, thit b; tng gi thnh cng trnh.-Phi di chuyn c s sn xut nhiu ln.-Khng c iu kin chuyn mn ha.

4. Phm vi p dng :-Tuyn ngn, khi lng nh.-Thi gian thi cng khng b khng ch.-Hn ch v cc iu kin cung cp my mc, thit b, nhn lc, cn b k thut,

ngun vn lu ng, vt liu...-Cng tc n b, gii phng mt bng, chun b din thi cng kh khn.- a hnh him tr, cht hp, khng c ng tm, khng cho php tp trung s

lng ln my mc, thit b, nhn lc v vt liu.


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5. Mt s lu khi phn on thi cng :-Khi lng cc on tuyn xp x nhau.-Chiu di on m bo cho my mc lm vic hiu qu, pht huy c nng

sut.-B tr cc m cung cp vt liu, kho tng, ln tri hp l cho cc on.-Xc nh thi im thi cng cc on hp l khng on no ri vo thi gian

thi cng bt li.-C gng li dng cc on hon thnh trc lm ng vn chuyn phc v

cng tc thi cng cc on sau.

Tit 2.2. Phng php t chc thi cng song song.1. Khi nim:

T chc thi cng theo phng php song song (P2TC2S2) l vic chia tuyn ngthi cng thnh nhiu on c khi lng thi cng xp x nhau; mi on giao cho mtn v thi cng hon thnh ton b cc hng mc cng tc t khu chun b n khu

hon thin.

2. c im :-Tuyn ng c chia thnh nhiu on ng c khi lng cng tc tng

ng.-Mi n v thi cng c giao ph trch thi cng 1 on ng.-Cc cng tc c trin khai v hon thnh ng lot trn ton b chiu di tuyn.-Cc ng nm ngang biu th thi hn hon thnh cc hng mc cng tc trn

ton tuyn, ng nm ngang trn cng biu th thi hn hon thnh tuyn ng.

3. u, nhc im :3.1. u im :

Do thi cng ng lot, hon thnh ng lot nn :-Rt ngn c thi gian thi cng; Cho php thi cng trong thi gian c thi tit

thun li; sm hon thnh cng trnh; nhanh quay vng vn lu ng.-Cc i thi cng khng phi di chuyn nhiu ln.


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3.2Nhc im :-Yu cu trong 1 thi gian ngn phi cung cp mt s lng my mc, thit b, vt

liu, cn b, cng nhn... sau li khng s dng na nn: gy kh khn cho khu cungcp; hiu qu s dng my mc, thit b khng cao; tng chi ph xy dng.

-My mc, thit b, nhn lc, vt liu tp trung mt khi lng ln trn din thicng hp d cn tr nhau. Nu t chc khng kho rt d b chng cho, nng sut gim,thit hi ln.

-Yu cu lng vn lu ng ln.-Khng c iu kin chuyn mn ha.-Gy kh khn cho cng tc iu hnh, qun l sn xut, khu kim tra.-nh hng ca cc iu kin kh hu thi tit xu n qu trnh thi cng rt nng

n.4. Phm vi p dng :

-Tuyn di, khi lng ln.-Thi gian thi cng yu cu nhanh, gp.-iu kin cung cp my mc, thit b, nhn lc, cn b k thut, ngun vn lu

ng, vt liu di do.-Cng tc n b, gii phng mt bng hon tt.-a hnh thun li cho php tp trung s lng ln my mc, thit b, nhn lc v

vt liu.-Phi c i ng CBKT ng o, gim st iu hnh tt c cc mi thi

cng.

Tit 2.3. Phng php t chc thi cng dy chuyn.Lch s :

T chc thi cng theo phng php dy chuyn (P2TC2DC) u tin c p dngtrong cc x nghip cng nghip t chc dy chuyn gia cng cc loi sn phm.Phngphp TC2ny hin c s dng rng ri cc nc tin tin do l P2TC2hini, c hiu qu kinh t cao.1. Khi nim :

T chc thi cng theo phng php dy chuyn (P2TC2DC) l vic ton b cngtc xy dng ng c phn chia thnh cc cng vic ring khc hn nhau; c xcnh theo mt trnh t cng ngh hp l; c giao cho cc n v chuyn mn,chuyn nghip m nhn, nhng c lin quan cht ch vi nhau, hon thnh trnton b chiu di tuyn.


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2. c im :Ton b cng tc XD c phn chia thnh cc cng vic khc hn nhau nh :

-Cng tc chun b;

-Cng tc xy dng cng;-Cng tc xy dng cu nh;-Cng tc xy dng k, tng chn;-Xy dng nn ng c k.lng tp trung;-Xy dng nn ng c k.lng dc tuyn;-Cng tc hon thin v gia c taluy;-Cng tc thi cng khun ng;-Cng tc thi cng mng ng;-Cng tc thi cng mt ng;

-Cng tc SX v gia cng VL, BTP v KCS;-Cng tc vn chuyn;-Cng tc hon thin.-Cng tc xy dng h thng thit b m bo an ton giao thng.Cc cng vic ny do tng n v chuyn nghip c trang b my mc v nhn lc

thch hp m nhn t lc bt u cho n khi hon thnh.Tin thi cng c th hin bng cc ng thng xin gc song song hoc

khng song song vi nhau.


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Ti mt thi im Tibt k trn trc tung, kt ng nm ngang ct ng tin thi cng ti mt im, ging xung trc honh s c chiu di on ng hon thnh cng vic y; nu l ng tin trn cng, s lchiu di on nghon thnh.


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Nu tc cc dy chuyn khng i, trong mt khong thi gian bng nhau (ca,ngy) s hon thnh cc on ng c chiu di bng nhau. Cc on lm sau k tipvi cc on lm trc to thnh 1 di lin tc, c th c s dng ngay phc v chocng tc thi cng cc on sau n.

Cc n v chuyn nghip sau mi ca, ngy thi cng s di chuyn u n theo tuynang lm v ln lt hon thnh khi lng trn ton tuyn.Sau khi i chuyn nghip cui cng hon thnh nhim v th tuyn ng c xy

dng xong v a vo khai thc, s dng.

3. u im :Cc on ng hon thnh u n, k nhau to thnh di lin tc, c th phc vthi cng cc on k tip, gim c cng tc lm ng tm; vi cc tuyn di c tha ngay cc on tuyn hon thnh vo khai thc, y nhanh thi k hon vn cang.

My mc, phng tin tp trung cc n v chuyn nghip nn gim c hhng, cht lng khai thc tt, n gin cho khuqun l; nng cao c nng sut, hc gi thnh xy dng.

Do chuyn mn ha cao nn:-T chc rt thun li;

-Nng cao c trnh k thut, nghip v cho cng nhn v cn b k thut;-Tng c nng sut lao ng;-Rt ngn c thi gian xy dng;-Nng cao c cht lng cng trnh.Theo thng k cc nc tin tin, vic p dng PPTC 2DC cho php gim gi

thnh 712%.

C th ni y l PPTC2cho php thc hin tt phng chm ca xy dng ngl : "Nhanh -Nhiu - Tt -R".4. Cc iu kin p dng :

PPTC2DC trong XD c im khc bit so vi vic TC2DC trong cc XN cng

nghip :-My mc, thit b, nhn lc phi di chuyn lin tc, cn sn phm l tuyn ngli c nh.


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-Cc thao tc i a s phi thc hin v hon thnh ngoi tri nn chu nhhng rt nhiu cc iu kin kh hu, thi tit.

V vy, m bo DC thi cng nhp nhng, u n, pht huy hiu qu phi mbo cc yu cu sau :Cc hng mc cng tc phi c tnh cht gn ging nhau, c k thut v cng ngh

thi cng tng t nhau (c tnh cht lp i lp li); mun vy chng phi c thit kc tnh nh hnh m bo thi cng d dng, d nm bt cng ngh.

Mun vy, cu nh-cng nn s dng cc cu kin lp ghp, c khu xp xnhau. Khng nn s dng qu nhiu loi khu m nn cn nhc phng n thay i sca. KCA nu c Eyckhc nhau nn chn phng n khc nhau v chiu dy 1 vi lp,khng nn khc nhau v vt liu.Khi lng cng tc phn b u trn tuyn n gin cho khu t chc DC, m

bo cc n v chuyn nghip c bin ch khng i c th hon thnh cc on ngc chiu di bng nhau trong mt n v thi gian.

Theo yu cu ny, cc cng tc: chun b; XD cng-cu nh; XD nn ng vngng bng; gia c taluy;XD mt ng; hon thin; XD thit b m bo ATGT thngd p ng.Cc VCN phi c trang b cc my mc thit b ng b, m bo tnh cn i

trong i vgia cc i vi nhau.Khu cung ng vt t, t chc vn chuyn phi m bo y , nhanh chng, kp

thi; cng tc duy tu, bo dng, sa cha xe my phi dc tin hnh thngxuyn m bo DCTC khng b gin on.i ng CBKT vcng nhn lnh ngh, c tnh t chc, k lut cao; chp hnh tt

mi quy trnh thao tc k thut.Ban iu hnh sn xut phi c t chc hp l, thng xuyn bm st hin trng,

kp thi pht hin nhng ch thit st, bt hp l trong n thit k k thut, thit k tchc thi cng kp thi iu chnh.T chc tt cc khu kim tra cht lng trc, trong v sau khi thi cng, m bo

"lm n u-xong n y".Phi hp nhp nhng vi cc n v c lin quan trong qu trnh thc hin d n (Ch

u t, n v TVTK, n v TVGS, n v TVK, ngn hng, kho bc...), nhanhchng thc hin cng tc n b, gii ta mt bng, nghim thu cc cng tc b chekhut, nghim thu chuyn giai on, nghim thu KL cng tc hon thnh, thanhton kp thi ngun vn lu ng u t.4. Phm vi p dng :

Lin h cc iu kin p dng PPTC2DC trong iu kin nc ta :-Khi lng cc tuyn c chiu di ln, khi lng ln khng nhiu.-Cc gi thu b "ct-xn" mt cch c hc nh, manh mn.-Cc yu t nh hnh, cc quan im thi cng cha c cn nhc k trong cc

n thit k hoctrong qu trnh ph duyt DA.-Tin bn giao mt bng nhiu d n rt chm do vng mc khu n b, gii

ta.-Khng c s phi hp gia cc Ch u t, cc ban QLDA nn thng xy ra

trng hp: cc nh thu thi cng ng lot cc cng trnh trong 1 thi gian ngn trongnm, khu cung ng vt t, vt liu rt kh m bo.

-S phi, kt hp gia cc n v trong mt d n cha cao, nhiu d n b nhtr do s qun l chng cho ca nhiu ban, ngnh trong cng mt d n; cc th tcqun l dn cn rt rm r, gy kh khn cho cc nh thu thc hin d n,


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gii ngn cc ngun vn u t rt chm.-Trang b my mc, thit b ca cc n v thi cng thng khng ng b, khng

m bo tnh cn i; i a s cha t kim tra c cht lng do mnh thc hin.-Trnh CBKT nhiu V cha cao; cha nm vng c quy trnh, quy phm,

cng ngh thi cng; trnh TC2rt hn ch.-Trnh cng nhn nhiu n v thi cng cha m bo, thc t gic, chp

hnh k lut cn hn ch.V vy, PPTC2DC cha c s dng ph bin, cha th pht huy hiu qu.

5. T chc dy chuyn :5.1. Dy chuyn chuyn nghip (DCCN): l n v c bn khi TC2theo PPDC.

-Mi mt DCCN (i CN) c t chc hon thnh mt hng mc cng tchoc 1 loi cng tc XD no .

-Mi mt DCCN c trang b mt lc lng thi cng nht nh nn kh nngcng tc ca i ni chung khng thay i.

-Thc t XD nhiu cng tc c khi lng thay i nn thng c 2 loi DCCNDCCN c c bin ch c nh, c tc thi cng dy chuyn thay i.

DCCN c tc thi cng DC khng i.Khi khi lng cng tc trong cc onthay i, iu chnh cho dy chuyn c tc khng i phi iu chnh lc lngthi cng, nn DC c bin ch thay i.

Ngoi ra, cn c cc DCCN c t chc thc hin cng tc ph tr (ln tri,kho tng...); cng tc khai thc v gia cng vt liu; cng tc ch to cc loi bn thnhphm vcu kin c sn; cng tc vn chuyn...


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5.2. Dy chuyn tng hp (DCTH):-Tp hp vthng nht ton b cc DCCN lm cc cng tc chun b v vn

chuyn; cng tc tp trung, dc tuyn... hon thnh ton b khi lng xy lp trntuyn ng mt cch lin tc, nhp nhng c gi l DCTH.6. Cc thng s c bn ca DC :6.1. Thi gian hot ng ca DC (Th):

L tng thi gian lm vic trn tuyn ca mi lc lng lao ng thuc DC.* Vi DCCN:tng thi gian lm vic trn tuyn ca mi lc lng lao ng thuc DC

k c thi gian khai trin v thi gian hon tt.* Vi DCTH:l tng thi gian k t khi DCCNu tin trin khai cho n khi DCCN

cui cng hon tt cng vic.6.2. Thi gian khai trin ca DC (Tkt):

L thi gian cn thit ln lt a ton b lc lng sn xut vo hot ngtheo ng trnh t cng ngh thi cng xc nh.* Vi DCCN:l thi gian k t khi chic my (hoc ngi) u tin thuc DC bt u

hot ng cho n khi chic my (hoc ngi) cui cng thuc DC bt u trinkhai. Thng Tktt vi gi n vi ca.* Vi DCTH:l tng thi gian k tkhi DCCN u tin bt u trin khai cho n khi

DCCN cui cng bt u hot ng. Thngthng Tkt t vi ca n vi chc ca.

Tktcng di th khi lng cng tc d dang cng ln, lng vn lu ng yu cucng nhiu, DC chu nh hng ca iu kin kh hu thi tit xu cng nng n.

V vy, khi TC2theo PPDC cn thit k sao cho Tktcng nh cng tt t (vi DCTH(v khng nn vt qu 10 15 ca).

Cng v l do trn, khi DC hot ng n nh, khng nn n ngng hotng gia chng, v s tn Tkt khi hot ng tr li.6.3. Thi gian hot ng thc ca DC (Tth):

Thi gian hot ng ca DC nh nu trn thng l thi gian thi cng tnh theolch. Trong khong thi gian ny, DC cn phi trin khai hot ng, v c th khng hot

ng trong cc ngy l, hoc do thi tit xu. V vy, thi gian hot ng thc ca DC sbng :

Tth= (Th- T1- Tkt)


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Vi :T1- thi gian DC phi ngng hot ng.T1= Max( Tng- thi gian DC phi ngng hot ng do ngh l;Tx- thi gian DC

phi ngng hot ng do thi tit xu). c th hon thnh tuyn ng ng tin , chiu di on ng DCTH c

th hon thnh trong thi gian hot ng thc phi ln hn hoc bng chiu di tuyn :L th = Tth.Vdc

Trong :. Vdc l tc dy chuyn (m/ca).. L l chiu di tuyn ng (m).y cng chnh l c s chn tc dy chuyn ti thiu.

6.4. Thi k hon tt ca DC (Tht):L thi gian cn thit ln lt a ton b lc lng sn xut ra khi mi hot

ng ca DC sau khi chng hon thnh cng vic ca mnh theo ng cng ngh TC.* Vi DCCN:l thi gian k t khi chic my (hoc ngi) u tin thuc DC hon ttcng vic cho n khi chic my (hoc ngi) cui cng thuc DC kt thc.* Vi DCTH:l thi gian k t khi DCCN u tin ktthc cho n khi DCCN cui

cng hon tt cng vic.Nu vn tc cc DCCN khng i vbng nhau thTkt= Tht.

6.5. Thi k n nh ca DC (T):L thi k hot ng ng thi ca cc DCCN thuc DCTH. y l thi gian

DCTH pht huy hiu qu cao nht, mi lc lng lao ng thuc DC c s dng chiu qu nht.

T= Th- (Tkt+ Tht)T quan h cho thy : nu (Tkt+ Tht)cng ln th T cng nh. iu ny cng khng nhthm nh hng bt li ca Tktv Tht.6.6. Tc ca DC (VDC):* ViDCCN: l chiu di on ng (m, km) m mt n v chuyn nghip hon thnh

mi cng tc ca mnh trong mt n v thi gian (ca, ngy).* Vi DCTH:l chiu di on ng hon thnh trong mt n v thi gian (ca, ngy).VDCl thng s c bn ca DC, n biu th mc trang b, trnh s dng mi lclng thi cng thuc DC, th hin nng sut cng tc ca n v chuyn nghip.


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VDCthng c xc nh da trn 2 c c :VDC

)/()( 1

min camTTT

L

T

LV

kthth

m bo lc lng thi cng thuc dy chuyn pht huy c nng sut, hiu qu.

Mun vy, thng phi xut pht t tin thi cng cho php hoc nng lc cng tc can v thi cng, thit k cc phng n TC2vi nhiu VDCkhc nhau, ri so snhchn phng nti u. Nh nu mc 5.1, cc DC c th cVDCkhng i hoc thayi. Khi gc i cng ln th tc DC cng cao

Trong thc t XD, chn VDC thng c 2 trng hp :Thi hn thi cng b khng ch. Lc ny chn VDCtheo 2 iu kin nu trn;

nng sut ca cc DCCN, c bit l cc DC sn xut VL, BTP, CKS, vn chuync xc nh trn c s VDC chn.Thi hn thi cng khng b khng ch. Lc ny chn VDCtheo iu kin th - theo

nng lc cng tc ca n v thi cng, c bit l cc DCCN sn xut VL, BTP, CKS,vn chuyn.6.7. on cng tc ca DC: l chiu di on ng (m, km) c th thi cng bng mtDC c lp trong mt khong thi gian nht nh ( nm qu, thng).on cng tc caDC ph thuc vo VDC, thi gian hot ng thc ca DC, qu trnh cng ngh thi cng.6.8. Chiu di DC (LDC):* Vi DCCN:l chiu di on ng (m, km) trn b tr ton b lc lng thi cngca n v chuyn nghip.

lDC= VDC. nitrong :nil s on DC trong Tkt.V d : chiu di DCCN thm BTN


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* Vi DCTH:l chiu di on ng (m, km) trn ton b lc lng thi cng thucDCTH ng thi hot ng.

)(111

mZalLp

k

k

m

j

j

n

i

i

DCDC

trong :

liDCl chiu di cc DCCN thuc DCTH (m);ajl chiu di cc on gin cch (m);Zkl chiu di cc on d tr (m);on gin cch aj: l chiu di on ng cn thit gia cc DCCN m quy

trnh, quy phm thi cng i hi; thng m bo cc kt cu thi cng trc c thigian hnh thnh cng .

aj= Vdc.Tgcj

Vi Tgcjl thi gian gin cch yu cu.V d :thi gian bo dng lp ct- gia c XM l 14 ngy; lp t gia c vi l 7 ngy.

on d tr Zk: l chiu di on ng d tr cn thit gia cc DCCN m bo khi

v mt l do no , DCCN i trc phi ngng hot ng, cc DCCN sau n vnhot ng bnh thng.

Zk = Vdc.Tdtk

Vi Tdtkl thi gian d tr cn thit. m bo c Tkt, Tht nh nh nu trn, khi thc s cn thit mi b tr cc onZk; rt ngn Tgci, c th s dng cc loi ph gia ninh kt nhanh, thc y qutrnh hnh thnh cng ca cc kt cu.6.9. Nhp ca DC (g):l khi lng cng vic n v chuyn nghip hon thnh trongmt n v thi gian.

)/,/,/()(

32

1camcamcamTTT

Q

T

Q

gkthth

trong :Q l khi lng cng tc.Khi g cng ln, DC c nh gi c nhp cng khn trng.7. nh gi hiu qu DC:C th nh gi qua h s hiu qu :

h

h

htkt

h

htkthhq

T

T

T

TT

T

TTTK

)(1

)(

Khi Khq

0,7 : TC2 theo P2DC mang li hiu qu cao.Khi Khq= 0,3 0,7 : nn TC

2phi hp P2DC vi P2TC2 khc.Khi Khq< 0,3 nn TC

2theo P

2T

2hoc P2S2.

cng c th nh gi qua h s t chc :

2

12

)(

hq

h

htkth

tc

K

T

TTT

K

Khi Ktc 0,85 : TC2theo P

2DC mang li hiu qu cao.Khi Ktc= 0,65 0,8 : nn TC

2phi hp P2DC vi P2TC2khc.

Khi Ktc< 0,65 nn TC2theo P

2T

2hoc P2S2.


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Tit 2.4. Phng php t chc thi cng hn hp.1. Khi nim :

Nh nu tit 2.3 :-Khi Khq= 0.3 0.7 hoc Ktc= 0.65 0.8 nn TC

2phi hp P2DC vi P2TC2khc.

-Khi Khq< 0.3 hoc Ktc< 0.65 khng nn TC2theo P

2DC.

T hnh thnh 1 P2

TC2

th 4 : phng php t chc thi cng hn hp (P2

TC2

H2

).P

2TC

2H2 rt a dng, n c th l kt qu phi hp ca P 2TC2DC vi mt hoc vi

P2TC

2khc; cng c th l s phi hp gia P2TC2T2 v P2TC2S2.

2. Phi hp gia P2TC2DC vi P2TC2T2:(Khi Khq= 0.3 0.7 hoc Ktc= 0.65 0.8)Trng hp 1 :cc cng tc khc TC2theo P2DC khng mang li hiu qu, phi TC2theo P

2T

2; ch t chc DC thi cng mt ng.

Trng hp 2 :my mc nhn lc t, khng th t chc mt lc nhiu DCCN.T chc tng DCCN thi cng tun t tng hng mc cng tc. Khi thi cng xong 1hng mc cng tc, t chc li DC thi cng hng mc cng tc tip theo.


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Trng hp 3 :thi cng trong iu kin thi tit khng thun li, my mc nhn lc t,cng nhn cha c tay ngh cao, trnh t chc ca CBKT cn thp, tuyn di.Trong tng on TC2theo P2DC, gia cc on TC2theo P2T2.

Trng hp 4 :khi cng tc n b, gii phng mt bng gp kh khn, my mcnhn lc t, cng nhn cha c tay ngh cao, trnh t chc ca CBKT cn thp.Trong tng on TC2theo P2DC, gia cc on TC2theo P2T2, chn cc on gii

phng mt bng thun li thi cng trc.

3. Phi hp gia P2TC2DC vi P2TC2S2:

(Khi Khq= 0.3 0.7 hoc Ktc = 0.65 0.8)Trng hp 1 :cc cng tc khc TC2theo P2DC khng mang li hiu qu, tin thicng yu cu nhanh-gp, phi TC2theo P2S2, ch t chc DC thi cng mt ng.


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Trng hp 2 :my mc nhn lc di do, thi gian thi cng yu cu nhanh-gp, trinkhai mt lc nhiu DC thi cng .


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Trng hp 3 :thi cng trong iu kin thi tit khng thun li, my mc nhn lckhng di do, cng nhn cha c tay ngh cao, trnh t chc ca CBKT chacao nhng tin thi cng yu cu nhanhgp.

4. Phi hp gia P2TC2T2 vi P2TC2S2:(Khi Khq< 0.3 hoc Ktc< 0.65)

P2TC

2T

2- P

2TC

2S

2


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