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  • TCVN 9436:2012

    1

    TCVN T I U C H U N Q U C G I A

    TCVN 9436:2012

    Xut bn ln 1

    NN NG T THI CNG V NGHIM THU Highway embankments and cuttings Construction and quality control

    H NI 2012

  • TCVN 9436:2012

    2

  • TCVN 9436:2012

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    Mc lc Trang

    Li ni u ............................................................................................................................................. 4

    1 Phm vi p dng ................................................................................................................................. 5

    2 Ti liu vin dn .................................................................................................................................. 5

    3 Thut ng v nh ngha ..................................................................................................................... 6

    4 Yu cu chung .................................................................................................................................... 7

    5 Vt liu nn ng ........................................................................................................................... 11

    6 Cng tc chun b thi cng nn ng ............................................................................................. 12

    7 Thi cng nn p .............................................................................................................................. 15

    8 Thi cng nn o .............................................................................................................................. 20

    9 Thi cng nn ng na o, na p v nn ng ci to, nng cp m rng ............................ 22

    10 Thi cng hng mc phng h v gia c ta luy ................................................................................. 23

    11 An ton v bo v mi trng trong qu trnh thi cng nn ng ................................................. 26

    12 Kim tra nghim thu ........................................................................................................................ 28

    Ph lc A (Tham kho) Chn my thi cng o p t ........................................................................ 31

    Ph lc B (Tham kho) Chn phng tin m nn t nn ng ..................................................... 32

    Ph lc C (Qui nh) Cch thit lp cc ch tiu kim sot cht lng m nn i vi lp t ln thng qua on thi cng th nghim ..................................................................................................... 34

    Ph lc D (Qui nh) Phng php th nghim xc nh tng lng mui d ha tan trong t. ............ 37

  • TCVN 9436:2012

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    Li ni u

    TCVN 9436:2012 do Vin Khoa hc v Cng ngh Giao thng vn ti bin son, B Giao thng vn ti ngh, Tng cc Tiu chun o lng cht lng thm nh, B Khoa hc v Cng ngh cng b.

    TCVN 9436:2012 c chuyn i t Quy trnh k thut thi cng v nghim thu nn ng st v nn ng B do B trng b GTVT ban hnh ngy 22-07-1975 theo quyt nh s 1660 QKT gi tt l Quy trnh 1975.

  • TCVN 9436:2012

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    TIU CHUN QUC GIA TCVN 9436:2012

    Xut bn ln 1

    Nn ng t Thi cng v nghim thu

    Highway embankments and cuttings Construction and quality control

    1 Phm vi p dng

    1.1 Tiu chun ny qui nh cc yu cu v vt liu, cng ngh thi cng v nghim thu khi xy dng mi hoc nng cp ci to hng mc cng trnh nn ng t trong cc trng hp thng thng.

    1.2 Tiu chun ny c th tham kho p dng cho vic thi cng v kim sot cht lng thi cng i vi cc trng hp nn ng c bit, ng chuyn dng hoc ng nng thn.

    2 Ti liu vin dn

    Cc ti liu vin dn sau y l cn thit p dng tiu chun ny. i vi cc ti liu vin dn ghi nm cng b th p dng bn c nu. i vi cc ti liu vin dn khng ghi nm cng b th p dng phin bn mi nht, bao gm c cc sa i, b sung (nu c).

    TCVN 5729:2012 ng cao tc Yu cu thit k.

    TCVN 4054:2005 ng t Yu cu thit k.

    TCVN 2737 Ti trng v tc ng. Tiu chun thit k.

    TCVN 8864:2011 Mt ng t Xc nh bng phng bng thc di 3m.

    22 TCN 332-06*) Quy trnh th nghim xc nh CBR ca t, dm trong phng th nghim.

    22 TCN 346-06*) Quy trnh th nghim xc nh cht nn, mng ng bng phu rt ct.

    22 TCN 333-06*) Quy trnh m nn t, dm trong phng th nghim.

    22 TCN 221*) Cng trnh giao thng trong vng c ng t. Tiu chun thit k.

    22 TCN 242*) nh gi tc ng mi trng khi lp d n.

    22 TCN 263*) Quy trnh kho st ng t.

    22 TCN 211*) o ng mm. Cc yu cu v ch dn thit k.

    22 TCN 262*) Quy trnh kho st thit k nn ng t p trn t yu.

    22 TCN 171*) Quy trnh kho st a cht cng trnh v thit k bin php n nh nn ng vng c hot ng st l.

    ASTM D 4914 99 Standard test method for density of soil and rock in place by the sand replacement. Method in a Test Pit (Phng php th nghim tiu chun cht ca t v ngoi hin trng bng thay ct).

    ASTM D 5030 04 Standard test method for density of soil and rock by the water replacement. Method in a Test Pit (Phng php th nghim tiu chun cht ca t v ngoi hin trng bng thay nc).

    __________________________________________ *): Cc tiu chun ngnh TCN s c chuyn i thnh TCVN

  • TCVN 9436:2012

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    AASHTO T267-86(2000) Determination of Organic Content in Soils by Loss on Ignition (Xc nh hm lng hu c trong t theo hn hp tn tht khi nung).

    AASHTO M145-91(2004) The classification of soils and soil-agregate Mixtures for highway construction purpose (Phn loi t v hn hp cp phi t cho mc ch xy dng ng t).

    3 Thut ng v nh ngha

    Trong tiu chun ny, s dng cc thut ng v nh ngha sau:

    3.1 Nn ng (Highway embankments and cuttings).

    Nn ng gm c nn p v nn o, l b phn c bn ca cng trnh ng t. Nn ng bao gm ton b phn o, p vt liu (o t hoc ; p t, hoc p vt liu khc) trong phm vi mt ct ngang thit k (thi cng) ca ng t, tr phn thuc kt cu o ng.

    Mt ct ngang thit k (thi cng) nn ng c gii hn bi mt ta luy nn ng, mt l ng, mt ranh gii b tr kt cu o ng v c phm vi lin quan cn phi p dng cc gii php x l tng cng v n nh ca nn mt ng (x l thay t, x l thot nc, b tr cng trnh chng v phng h nn ng, x l nn t yu, x l chng st l v.v)

    3.2 Nn ng thng thng (Normal highway embankments and cuttings).

    Loi c th thi cng o, p bng cc loi my lm t thng thng v ch cn p dng cc gii php x l thng thng trong phm vi mt ct ngang thit k (thi cng), k c cc gii php x l thot nc v phng h ta luy thng thng.

    3.3 Nn ng c bit (Special highway embankments and cuttings).

    Cc loi nn ng khng th thi cng bng cc my lm t thng thng v/hoc cn phi p dng cc gii php x l c bit tng cng v n nh nh ng qua vng t yu, vng c cc hin tng a cht d gy st l, vng c cng hoc cn phi p dng cc gii php cu trc c bit nh nn p

    3.4 Nn p (Embankment).

    Loi nn ng hnh thnh bng cch p t, (hoc vt liu khc) cao hn mt a hnh t nhin ti ch. Thn nn p c gii hn bi mi ta luy p, l p, ranh gii b tr kt cu o ng v c phm vi x l thay t nm di mt a hnh t nhin (nu c).

    Trong tiu chun ny nn p c cp phn bit 03 trng hp:

    3.4.1 Nn p t (Earth fill embankment).

    t cc loi c th ln di 30% khi lng l , cui si c kch c t 19 mm tr ln cho n c ht ln nht l 50 mm. Vt liu p loi ny c th xc nh c cht tiu chun trong phng th nghim theo 22 TCN 333-06.

    3.4.2 Nn p t ln (Earth - Rock embankment).

    t ln t 30% n 70% cc loi c kch c t 50 mm tr ln cho n kch c ln nht cho php qui nh ti 5.4.

  • TCVN 9436:2012

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    3.4.3 Nn p (Rock fill embankment).

    Cc loi vi kch c t 37,5 mm tr ln chim 70% khi lng. Trong tiu chun ny khng cp n vic thi cng nn p .

    3.5 Nn o (Cuttings).

    Loi nn ng hnh thnh bng cch o t, xung thp hn mt a hnh t nhin ti ch.

    3.6 Nn na o, na p (Embankments and cuttings).

    Loi nn ng trn cng mt mt ct ngang gm mt phn nn o v mt phn nn p.

    3.7 Mi ta luy (Slope).

    Ranh gii hai bn ca nn o (ta luy o) hoc ranh gii hai bn ca nn p (ta luy p) hoc l ranh gii hai bn ca nn na o, na p.

    3.8 Khu vc tc dng ca nn ng v lp 30 cm nn ng trn cng (Subgrade and the upper layer of Subgrade).

    Khu vc ny l phn nn ng trong phm vi chiu su bng 80 cm n 100 cm k t y kt cu o ng tr xung. y l phm vi nn ng cn c sc chu ti cao cng vi kt cu o ng chu tc ng ca ti trng bnh xe truyn xung. ng c nhiu xe nng chy th phm vi chiu su khu vc tc dng ly tr s ln.

    Trong phm vi chiu su khu vc tc dng thng c phn chia thnh 02 phn:

    Phn 30 cm trn cng trc tip vi y kt cu o ng (lp nn trn cng hoc lp nn thng);

    Phn cn li ca chiu su khu vc tc dng (50 cm n 70 cm) pha di.

    Nu kt cu nn o ng c b tr thm lp y mng th lp ny cng thuc khu vc tc dng ca nn ng v thay th cho lp 30 cm nn ng trn cng.

    4 Yu cu chung

    4.1 Nn ng phi c thi cng t ng kch thc cc yu t hnh hc nh trong thit k. Sai s cho php c quy nh ti Bng 1.

    Bng 1: Sai s cho php (so vi thit k) v cc yu t hnh hc ca nn ng sau thi cng

    Yu t Loi v cp hng ng Cch kim tra ng cao tc cp I, II, III

    ng cp IV, V, VI

    1. B rng nh nn Khng c nh hn thit k

    Khng c nh hn thit k

    50 m di o kim tra mt v tr.

    2. dc ngang v dc siu cao (%)

    0,3 0,5 C 50 m o mt mt ct ngang bng my thu bnh.

    3. dc ta luy (%)

    Khng c dc hn thit k

    +10 (*)

    Khng c dc hn thit k

    +15 (*)

    C 20 m o mt v tr bng cc loi my o c.

  • TCVN 9436:2012

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    Bng 1: Sai s cho php (so vi thit k) v cc yu t hnh hc ca nn ng sau thi cng (tip theo)

    4. V tr trc tim tuyn (mm)

    50 100 C 50 m kim tra mt im v cc im TD (***), TC (****) ca ng cong.

    5. Cao trn mt ct dc (mm)

    +10; -15

    (+10; -20) (**)

    +10; -20

    (+10; -30) (**)

    Ti trc tim tuyn. C 50 m kim tra mt im.

    6. bng phng mt mi ta luy o bng khe h ln nht di thc 3 m - Mi ta luy nn p (mm)

    - Mi ta luy nn o (mm)

    30

    50

    50

    80

    - Khng p dng cho mi ta luy . - Trn cng mt mt ct ngang, t thc 3 m r lin tip trn mt mi ta luy pht hin khe h ln nht - C 20 m kim tra mt mt ct ngang.

    7. Cc loi rnh khng xy hoc cha gia c: - Cao y rnh (mm)

    - Kch thc mt ct

    - dc ta luy rnh

    - gy khc ca mp

    rnh (mm)

    +0, -20

    Khng nh hn thit k

    Khng dc hn thit k

    + 50

    +0, -30

    Khng nh hn thit k

    Khng dc hn thit k

    + 70

    C 50 m o cao hai im bng my thu bnh C 50 m o mt mt ct ngang

    C 50 m o mt v tr.

    Dng thc dy 20 m cng v o chnh lch gia mp rnh vi thc. C 50 m o mt v tr.

  • TCVN 9436:2012

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    Bng 1: Sai s cho php (so vi thit k) v cc yu t hnh hc ca nn ng sau thi cng (kt thc)

    8. Cc rnh xy - Cng va xy

    - V tr tim rnh (mm)

    - Kch thc mt ct (mm)

    - B dy lp xy

    - Kch thc lp m mng

    - Cao y rnh (mm)

    - gy khc ca mp rnh (mm).

    t yu cu thit k

    50

    30

    Khng nh hn thit k

    Khng nh hn thit k

    10

    + 50

    t yu cu thit k

    100

    50

    Khng nh hn thit k

    Khng nh hn thit k

    15

    + 70

    Vi mi t l pha trn c mt ca thi cng lm hai t mu th cng . o bng my kinh v, c 50 m o hai v tr tim. C 50 m o mt mt ct.

    C 50 m o mt v tr.

    C 50 m o mt v tr.

    C 50 m o mt im.

    Nh vi rnh khng xy.

    (*) p dng cho nn o, p nhng khng c trn mt on ng di lin tc qu 30m;

    (**) p dng cho nn o, p .

    (***) TD cc tip u trong ng cong.

    (****) TC cc tip cui trong ng cong.

    4.2 Mt mi lp t p nn ng v mt trn cng ca nn ng sau thi cng (c vi nn o v nn p) phi t c bng phng qui nh di y:

    - i vi ng cao tc, ng cp I, cp II, bng phng phi t mc 100% s khe h di thc di 3 m khng vt qu 15 mm;

    - i vi ng t cc cp khc, bng phng phi t mc 70% s khe h o c di thc di 3 m khng vt qu 15 mm, cn li khng vt qu 20 mm.

    CH THCH:

    - Cho php c 5% s khe h vt qu tr s khe h ln nht nhng tr s khe h ln nht khng c qu 1,4 ln tr s qui nh tng ng vi mc bng phng yu cu;

    - Phng php o v mt o kim tra bng phng tun th TCVN 8864:2011.

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    4.3 Loi t v sc chu ti ca vt liu lm nn ng phi tha mn cc yu cu qui nh ti iu 5. Nn ng phi t cht m nn yu cu qui nh ti Bng 2

    Bng 2: cht m nn yu cu i vi nn ng (phng php m nn tiu chun theo 22 TCN 333-06).

    Loi v b phn nn ng Phm vi su tnh t

    y o ng tr

    xung (cm)

    cht K ca nn ng

    ng cao tc

    ng cp I n

    cp IV

    ng cp V n

    cp VI

    Nn p

    Khi o ng dy trn 60cm 30 1,0 0,98 0,95

    Khi o ng dy di 60cm 50 1,0 0,98 0,95

    Bn di chiu su ni trn

    Cho n ht thn nn p (trng hp vt liu mi p).

    0,98 0,95 0,93

    t nn t nhin(*) Cho n 80 0,93 0,90

    Cho n 100 0,95

    Nn o v khng o khng p (nn thin nhin (**))

    30 1,0 0,98 0,95

    30 n 80 0,93 0,90

    30 n 100 0,95

    (*) Trng hp ny l trng hp nn p thp khu vc tc dng c mt phn nm vo phm vi t nn thin nhin;

    (**) Nu nn thin nhin khng t cht yu cu Bng 2 th phi o phm vi khng t ri m nn li cho t yu cu.

    4.4 Yu cu m nn i vi cc lp nn ng p bng t ln c qui nh ti 7.3.11.

    4.5 H thng thot nc trong phm vi nn ng phi c thi cng ng nh yu cu thit k (v v tr, kch thc, vt liu) v cht lng thi cng phi t cc yu cu quy nh trong tiu chun ny (Bng 1).

    4.6 Trong qu trnh thi cng nn ng phi c cc bin php cn thit bo m tuyt i an ton cho ngi v thit b thi cng, cho ngi v ti sn ca dn c ln cn.

    4.7 Trong qu trnh thi cng nn ng phi c cc bin php cn thit hn ch cc tc ng xu n sinh thi v mi trng, hn ch bi v ting n, bo v cy ci vn c; c bit l phi c bin php x l tho ng cc ph thi do thi cng nn ng to ra (bao gm c t o tha ra), khng tu tin t v ph thi, khng c tu tin ly vt liu p gy nh hng xu n mi trng v cnh quan thin nhin cc khu vc ln cn.

    4.8 Trong qu trnh thi cng phi tun th cc qui nh ca php lut v bo v cc di sn vn ho, di tch lch s; nu pht hin cc di sn, c vt phi nh ch thi cng, gi nguyn hin trng v bo co vi cc cp, cc c quan c thm quyn x l.

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    5 Vt liu nn ng

    5.1 Khng c s dng trc tip cc loi t di y p bt c b phn no ca nn ng:

    - t bn, t than bn (nhm A-8 theo AASHTO M145);

    - t mn ln hu c c thnh phn hu c qu 10,0%, t c ln c v r cy, ln rc thi sinh hot (AASHTO T267-86);

    - t ln cc thnh phn mui d ha tan qu 5% (cch th nghim xc nh xem ph lc D);

    - t st c trng n cao vt qu 3,0% ( th nghim xc nh trng n theo 22 TCN 332-06);

    - t st nhm A-7-6 (theo AASHTO M145) c ch s nhm t 20 tr ln;

    Khi khng c cc loi t khc, phi c bin php ci to cc loi t ni trn dng lm vt liu p nn ng nh: loi b cc thnh phn bt li, x l t xu bng cch trn thm vi, trn thm ct hoc p dng cc bin php tng thm cht m nn, hn ch nc thm nhp... Cc bin php ni trn phi c nh gi thng qua th nghim trong phng, hin trng v phi c ph duyt theo cc quy nh v qun l d n.

    5.2 Khng c dng t bi nhm A-4 v A-5 (theo phn loi AASHTO M145) xy dng cc b phn nn ng di mc nc ngp hoc mc nc ngm v khng nn dng chng trong phm vi khu vc tc dng ca nn ng.

    5.3 Vt liu p nn phi c sc chu ti CBR nh nht nh qui nh ti Bng 3.

    Bng 3: Quy nh v sc chu ti (CBR) nh nht

    Phm vi nn ng tnh t y o ng tr xung

    Sc chu ti (CBR%) ti thiu

    Nn cho ng cao tc, cp I, cp II

    Nn cho ng cp III, cp IV c s dng mt ng cp cao A1

    Nn cho ng cc cp khc khng s dng mt ng cp cao A1

    Nn p

    - 30 cm trn cng

    - T 30 cm n 80 cm

    - T 80 cm n 150 cm

    - T 150cm tr xung

    Nn khng o, khng p v nn o

    - 30 cm trn cng

    - T 30 cm n 100 cm vi ng cao tc, cp I, cp II, cp III v n 80 cm vi ng cc cp khc

    8

    5

    4

    3

    8

    5

    6

    4

    3

    2

    6

    4

    5

    3

    3

    2

    5

    3

    CH THCH:

    Tr s CBR c xc nh theo 22 TCN 332-06 tng ng vi cht m nn yu cu ti Bng 2

  • TCVN 9436:2012

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    5.4 Kch c ht ln nht ca cc ht si cui, ln trong t p dng cho trng hp p t ln l 100 mm khi p trong phm vi khu vc tc dng ca nn ng v l 150 mm khi p phm vi di khu vc tc dng. Khi p trong phm vi di khu vc tc dng bng loi cng va v cng (cng chu nn trn 20 MPa) th c ht ln nht cn c th cho php bng 2/3 b dy m nn lp t ln lc thi cng. Nu l loi mm hoc c ngun gc t phong ha mnh (cng chu nn t 20 MPa tr xung) th kch c ht ln nht c th bng vi b dy m nn nhng tr s sc chu ti CBR ca chng vn phi t yu cu qui nh ti Bng 3.

    5.5 Vt liu p bao.

    5.5.1 Khi nn ng p bng ct, nn ng phi c p bao c hai bn mi ta luy v phn nh nn pha trn nh yu cu 7.4.4 TCVN 4054. Trong trng hp ny t p bao hai bn ta luy cng phi ph hp vi cc yu cu ti 5.1, 5.2, 5.3 v 5.4.

    5.5.2 Nu kt hp, lm chc nng lp y mng, vt liu p bao pha nh nn phi ph hp vi qui nh ti 2.5.2 ca 22 TCN 211-06

    5.5.3 Nu kh kim c t p bao ph hp phi xut gii php thay th khc p ng cc yu cu c qui nh ni trn. Gii php thay th phi c trnh duyt theo qui nh v qun l d n.

    6 Cng tc chun b thi cng nn ng

    6.1 Trc khi khi cng thi cng nn ng, phi th st hin trng, phi nghin cu tm hiu k h s thit k v lp thit k t chc thi cng chi tit, trong phi qui nh gii php phn phi t chi tit (t o ra chuyn n u hoc i u; t p ly u), phi xc nh cc loi my mc v thit b thi cng thch hp tng ng cho tng on nn ng, phi qui nh cc gii php bo m cht lng, bo v mi trng v an ton lao ng.

    6.2 Trc khi khi cng thi cng nn ng phi c ng tm iu kin cho xe my i li, hot ng trong mi thi tit. ng tm v s hot ng ca xe, my trn ng tm khng c gy tc ng xu n hot ng ca cc ng hin c, gy ch tc hoc mt an ton, gy tc ng xu n cc cng trnh khc, n vic canh tc v sinh hot ca dn c trong vng ln cn. Trng hp thi cng nng cp ci to ng c th nh thu phi c trch nhim duy tu bo dng ng, thc thi cc bin php bo m an ton giao thng v bo m s lu thng bnh thng ca tt c cc phng tin khc vn i li trn ng.

    6.3 Trc khi thi cng nn ng phi c cc c s th nghim v t, phc v cho vic kim sot cht lng thi cng.

    6.4 Phi chun b lc lng xe my, thit b thi cng tng ng vi yu cu v tin trong bn thit k t chc thi cng c duyt. Cn b tr nh xng v lc lng bo qun, bo dng, sa cha xe my thi cng. Khuyn khch s dng xe my thit b thi cng tin tin, hin i.

    6.5 Chun b hin trng thi cng.

    6.5.1 Khi phc v c nh cc cc nh v tr tuyn ng thit k.

    Cng vic ny phi t c cc yu cu quy nh tng ng vi mc ch khi phc tuyn trn thc a t 15.2 n 15.8 tng ng vi giai on kho st lp thit k bn v thi cng Quy trnh kho st ng t 22 TCN 263 -2000 k c v cc cc cn khi phc v v chnh xc ca vic o c khi khi phc cc.

  • TCVN 9436:2012

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    6.5.2 Cng vi vic khi phc tuyn phc v cho qu trnh thi cng sau ny cn phi tin hnh b sung thm li trc a khng ch mt bng v khng ch cao (li khng ch o v) c th l b sung cc mc (ta , cao) dc tuyn. Cc mc ny thng b tr cch nhau 0,5 km dc tuyn v b tr ti cc v tr cu ln, cu trung, hm, ch giao nhau khc mc, ch c nn p cao o su, ch c cng trnh chng nn ng...

    Mc chnh xc v o c v cc ch tiu k thut khi thc hin li khng ch o v ny phi tng ng vi yu cu o v a hnh t l 1/500 qui nh Ph lc 6.4 v 6.5 ca quy trnh Kho st ng t 22 TCN 263 2000 khi thi cng nn ng cao tc, ng cp I, ng cp II v tng ng vi yu cu o v a hnh t l 1/1000 i vi ng t cp III tr xung.

    6.5.3 Khi khi phc tuyn ng thi phi xc nh r phm vi gii phng mt bng phc v thi cng nn ng v cc cng trnh trn ng.

    6.5.4 Dn dp mt bng thi cng nn ng.

    Trc khi thi cng xy dng nn o, nn p cn phi dn dp cy c, bc cc lp t hu c v dn dp cc chng ngi vt trong phm vi thi cng vi cc yu cu c th sau y:

    - Dn sch cc hn to cc on nn o v nn p thp di 1,5 m gy cn tr xe my thi cng. Nu c th tch ln hn 1,5 m3 th phi dng n mn ph nh cho xe my chuyn i khi phm vi thi cng.

    - Phi cht pht cy, k c cc cnh cy t ngoi vn vo phm vi thi cng; phi nh sch gc cy nhng on nn p thp di 1,5 m, cc trng hp khc phi cht cy nhng c th li gc cao hn mt t t nhin di 10 cm (h nh gc cy phi c p t li v m nn cht nh mt phn ca nn ng).

    - Phi di di hoc x l cc cng trnh hoc chng ngi vt khc (k c m m, ging nc, ao chum...) vn nm trong phm vi thi cng, theo ng yu cu v ch dn ca h s thit k;

    - Phi bc sch lp t b mt, lp t hu c, ry sch c trong phm vi thi cng (k c cc v tr ly t p). Nn tr liu vic tn dng t hu c bc ra cho cc khu cng vic hon thin nn ng.

    - Trong qu trnh dn dp mt bng bin php b hoc tiu hy cc ph thi phi tun th php lut v cc quy nh a phng, khng c nh hng n dn c v cc cng trnh ln cn. Nu ch ph thi nm ngoi phm vi ch gii gii phng mt bng th phi c s cho php ca chnh quyn a phng.

    6.5.5 Bo m thot nc hin trng thi cng.

    Trc v trong qu trnh thi cng nn ng phi lun c cc bin php thot nc hin trng (k c i vi nc mt v nc ngm) to thun li cho vic bo m tin v cht lng thi cng, ng thi khng nc nh hng n dn c ln cn.

    - Phi lun u tin thi cng trc cc cng trnh thot nc v x l nc ngm c trong h s thit k nh rnh nh, cng trnh dch chuyn mng thot nc, ho ct hoc thu thot nc ngm, cng trnh rnh chn nc khng cho thm vo y nn p trn sn dc...

    - Khi cn thit phi lm thm cc cng trnh thot nc tm thot nc hin trng thi cng, khng nc ng li hoc thm vo mt bng thi cng v gy xi l mi ta luy thi cng.

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    - Trong qu trnh thi cng, mt mi lp o hoc lp p u phi to dc 2% n 4% (dc ngang hoc dc dc) v cc mng tm thot ra ngoi phm vi hin trng thi cng. Nht thit khng nc ma ng thnh vng trn mt cc lp o, lp p ang thi cng.

    6.5.6 nh v cc im c trng ca nn ng.

    - Trc khi thi cng phi kim tra tng mt ct ngang thit k trn thc a v da vo c nh (bng cc hoc cc tiu) cc v tr c trng ca nn ng trn thc a nhm bo m thi cng nn ng ng vi hnh dng kch thc thit k. Cc v tr ny gm cc chn mi ta luy p, nh mi ta luy o, ranh gii ly t thng u v phm vi c t tha.

    Cc cc hoc cc tiu phi d nhn bit v c bo v tt trong sut qu trnh thi cng. i vi ng cao tc cp I, II v cc ch o cao, p su, khong cch dc gia cc cc tiu ti hin trng khng c qu 50 m trn ng thng v 10 m trn ng cong; sai s v tr ca cc cc nh v cho php bng mc chnh xc v o c qui nh ti 6.5.2.

    - Mi khi o hoc p c 3 m n 5 m (chiu cao) hoc vi cc mt ct c bc thm, mi khi o hoc p c mt bc thm phi kim tra li v tr trc tim tuyn ng v kch thc mt ct ngang (bao gm c dc ta luy).

    6.6 Th nghim nh gi t dc tuyn v vt liu p ly m.

    Yu cu i vi cng vic ny l nh gi c t hoc vt liu xy dng nn o, nn p trn thc t dc tuyn c ph hp vi cc quy nh iu 5 khng, t c cc bin php x l tng thch.

    6.6.1 i vi tt c cc on nn o d kin ly t chuyn sang nn p v tt c cc m t ly t p u phi tin hnh ly mu th nghim kim tra cc ch tiu m t nhin, gii hn chy, ch s do, cht tiu chun, ch tiu sc chu ti v trng n t th nghim xc nh CBR. Khi c cc loi t cp ti 5.1 v 5.2 th phi kim tra hm lng hu c, hm lng mui d ha tan v phi th nghim xc nh tn nhm t theo AASHTO M-145. Mt ly mu th nghim ti thiu l hai v tr cho mi loi t ca mi on.

    Nu mi on nn o hoc mi m t c nhiu lp t khc loi, khc ngun gc th phi ly mu th nghim kim tra vi tng loi .

    6.6.2 i vi t y nn p v trong phm vi khu vc tc dng ca nn o sau khi o n cao thit k cng phi tin hnh ly mu t th nghim cc ch tiu nh qui nh 6.6.1. Mt ly mu th nghim ti thiu l hai v tr cho mt km hoc hai v tr cho mt on nn c t khc loi.

    6.6.3 Trong mi trng hp qui nh ti 6.6.1 v 6.6.2, mi ch tiu c nh gi bng tr s trung bnh ca ba mu th nghim.

    6.7 on thi cng th nghim.

    6.7.1 Trc khi thi cng i tr, phi lm th nghim mt on di ti thiu 100 m trong cc trng hp sau:

    - Nn p t i vi cc ng cao tc, ng cp I, cp II v cp III;

    - Nn p bng t ln ;

    - Nn o hoc p c p dng k thut, cng ngh hoc vt liu mi;

    - Nn p bng ct c p bao;

    - Nn ng c bit (trn t yu, nn vng st l, nn o cng, nn p bng vt liu nh...).

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    6.7.2 Ni dung, yu cu th nghim.

    Kt qu th nghim phi khng nh c cc ni dung sau:

    + Chnh xc ha thnh phn v cc ch tiu vt liu xy dng nn ng.

    + Khng nh cc thng s chnh ca cng ngh m nn cn t c trong qu trnh thi cng i tr:

    Trnh t m nn;

    T hp v quy cch cc my m nn cn thit;

    B dy ri lp vt liu trc khi m nn;

    m m nn tt nht v sai s cho php.

    + Khng nh cc ch tiu v phng php kim sot cht lng trong qu trnh thi cng, c bit l i vi trng hp nn p ln phi thc hin theo ch dn ph lc C.

    + Khng nh cng ngh v phng n t chc thi cng (nu cn, c th iu chnh t chc v tin thi cng chung).

    7 Thi cng nn p

    7.1 Ly t (vt liu) p.

    7.1.1 Ngoi vic phi tun th yu cu v bo v mi trng v cnh quan thin nhin qui nh 4.7, vic khai thc vt liu p phi kt hp tt vi quy hoch t ai a phng v quy hoch thot nc nn ng (ly t o cng trnh thy li, cng trnh thot nc p); hn ch ti a vic chim dng rung t; tn dng t cn ci, phong ha; khng ly t di mc nc ngm; o ly t khng c nh hng n n nh ca ta luy v n nh ca c nn ng.

    7.1.2 Khng c ly t thng u hai bn ng cao tc v hai bn phm vi u cu.

    7.1.3 Trc khi ly vt liu p phi kim tra cc c trng ca vt liu theo qui nh ti 6.6 xem c ph hp vi cc yu cu ti iu 5 khng.

    7.2 X l mt nn t nhin trc khi p thn nn ng.

    7.2.1 Khi mt nn t nhin c dc ngang di 20% phi o b lp t hu c ri lu lp nn t nhin trn cng t cht K=0,9 ( vi ng cao tc, ng cp I, cp II ) hoc K=0,85 ( vi ng cc cp khc ) trc khi ri vt liu p cc lp thuc thn nn ng pha trn.

    7.2.2 Khi mt nn t nhin c dc ngang t 20% n 50%, phi kt hp nh bc cp v o b lp t hu c trc khi p. Chiu rng bc cp nn ln hn 2 m, chiu cao bc cp nn ly bng bi s ca b dy lp t m nn ty loi lu sn c. Mt bc cp phi lu t yu cu nh qui nh ti 7.2.1 v c dc vo pha trong sn dc ti thiu bng 2%.

    7.2.3 Phi c bin php hn ch nc thm vo mt ranh gii gia mt nn t nhin v y thn nn p khi p trn sn dc.

    7.2.4 Khng c p nn p bng t trc tip trn mt nn t nhin c dc ngang t 50% tr ln.

    Trng hp p trn mt nn t nhin c dc ngang t 50% tr ln nhng c cng trnh chng pha di dc (tng chn cc loi) th vic x l mt nn t nhin pha trong cng trnh chng cng phi tun th quy nh ti 7.2.2 d vt liu p l t hay .

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    7.2.5 Khi mt nn t nhin c cc h, cc ch trng, phi vt sch y v dng vt liu ph hp vi qui nh iu 5 p y chng; phi phn lp p, lu ln t cht yu cu qui nh ti 7.2.1

    7.2.6 Phi vt sch, o b lp t hu c v c bin php ht ht nc trc khi p thn nn ng qua vng rung la nc.

    7.2.7 Cc trng hp di y cn phi c thit k bin php x l mt nn t nhin c duyt trc khi p thn nn ng:

    - Nn p cao, nn p bng , nn p bng vt liu nh;

    - p qua h, ao, p ln ra sng, sui v vng nc ngp;

    - p qua vng c nc ngm cao, c vt l nc ngm;

    - Mt nn t nhin l t ln ;

    - Mt nn t nhin c dc ngang ln hn 50%;

    - Mt nn t nhin cc on nn ng c bit qui nh ti 1.2 v iu 3;

    - p m rng nn ng khi nng cp, ci to ng (bin php x l bao gm x l mt nn t nhin v c mt mi ta luy nn p c nhm bo m lin kt tt gia nn p c vi nn p m rng v bo m phn p m rng khng b ln x).

    7.3 Cng tc ri v m nn.

    7.3.1 Cc loi t, hoc t ln c c trng khc nhau phi c p thnh cc lp hoc cc on nn ng ring, khng c p ln ln. Phi p tng lp t ch a hnh thp nht ln cao dn, khng c p ln t ch cao xung ch thp. Mi lp theo chiu ngang phi p bng cng loi vt liu trn ton b b rng tng ng v tng chiu dy sau khi lu ln ca lp vt liu cng loi khng nn nh hn 30 cm, ring vi lp nn ng trn cng chiu dy sau khi lu ln ti thiu l 10 cm.

    Nu s dng c loi t c tnh thm thot nc tt v loi c tnh thm thot nc km th lp thm thot nc km phi p di vi mt lp sau khi lu ln c dc ngang t 2% n 4%, sau mi p loi t c tnh thm thot nc tt ln trn.

    Phi p loi t c t s sc chu ti CBR thp pha di v cao pha trn ph hp vi yu cu Bng 3.

    7.3.2 Trng hp p t ln phi c bin php phn b tng i u kch c ln 10 cm n 15 cm trong mi lp ri.

    7.3.3 B dy ri mi lp trc khi lu ln ty thuc t hp cng c m nn c xc nh thng qua on thi cng th nghim nh qui nh ti 6.7.1 v 6.7.2.

    Trng hp nn p thng thng ca ng cp thp (t cp IV tr xung) khng bt buc phi lm on thi cng th nghim th b dy ri mi lp c th c xc nh thng qua kt qu kim tra cht t c sau t thi cng p u tin. B dy ri mi lp ph thuc phng tin m nn c th tham kho iu B.II Ph lc B

    7.3.4 Trc khi m nn, t ri phi c m tt nht Wo tng ng vi kt qu m nn tiu chun. Sai s chp nhn v m l 2% so vi Wo. Nu t c m vt qu m tt nht 2% phi hong kh v nh hn 2% nn ti thm nc vo xi u; trng hp p bng ct khng c ti sng nc nc thm xung c cc lp pha di thi cng. Khng c trn t kh vi t qu m p.

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    7.3.5 Cc my thi cng nn p phi c chn ty loi vt liu p, c im cng trnh (din rng, din hp), a hnh, chiu cao nn p, c ly vn chuyn c xt n yu t v tin v v kinh t (tham kho Ph lc A).

    C th tham kho Bng B.1 ph lc B chn loi thit b m nn. Nn dng lu chn ng nng t 15 tn tr ln khi m nn cc lp p t ln .

    7.3.6 Bt k dng loi phng tin m nn no u phi tun theo cc quy nh sau:

    - Phi m nn ng u sut b rng nn ng tng lt trn mi on thi cng theo trnh t t ch thp n ch cao (t hai bn vo gia trc tim nn ng on ng thng v t pha bng ln pha lng cc on ng cong).

    - Cc vt lu lin tip phi ln nhau t 15 cm n 20 cm, vt m lin tip phi ln nhau t nht 1/3 b rng vt m.

    7.3.7 X l ch ni tip gia cc on thi cng nn p

    Gia hai on thi cng theo chiu dc trc ng, phi ri t to ra mt dc nghing 30o (so vi mt lp ri nm ngang) hoc to bc cp ni tip dc gia hai on vi kch thc bc cp nh qui nh ti 7.2.2

    Phi tng cng m nn khu vc ni tip gia hai on khi thi cng p on sau. Nu to bc cp, phi m nn k mt mi bc cp trc khi p cc lp trn n.

    7.3.8 Khi p b mt lp mng di 10 cm, trc ht phi cuc bm mt lp t pha di, ti m va phi ri mi c p b bng t cng loi..

    7.3.9 Trong qu trnh p phi ch trng cc bin php thot nc xem 6.5.5.

    7.3.10 Kim tra cht lng p t trong qu trnh thi cng

    - Mi lp t m nn xong u phi kim tra cht vi mt t nht l hai v tr trn 1000 m2, nu khng 1000 m2 cng phi kim tra hai v tr; khi cn c th tng thm mt kim tra v ch trng kim tra c cht cc v tr gn mt ta luy.

    - Kt qu kim tra phi t tr s cht K ti thiu qui nh Bng 2 ty theo v tr lp m nn. Nu cha t th phi tip tc m nn hoc xi ln ri m nn li cho cht.

    - Khi kim tra bng phng php rt ct hoc ti nc phi o h th nghim n y lp t m nn. Khi dng phng php dao vng, phi ly mu vo dao vng su chnh gia lp m nn. Nu dng thit b o cht bng cc phng php vt l, phi thao tc v t u o ng theo vn bn ch dn km theo thit b ca nh sn xut.

    7.3.11 Kim tra t p ln trong qu trnh thi cng

    + Nu si cui, ln trong t l loi mm v rt mm c cng chu nn t 20 MPa tr xung th vic kim tra cht lng m nn t ln c thc hin tng t nh khi m nn t quy nh ti 7.3.10.

    + Nu si cui, ln trong t l loi cng va v rt cng c cng chu nn ln hn 20 MPa, vic kim tra cht lng m nn i vi mi lp m nn c thc hin nh sau:

    - Trong qu trnh thi cng mi lp phi kim tra ti thc a (c ghi chp thnh vn bn) cc thng s ca cng ngh m nn thc hin gm b dy lp ri, m, th t, s lt lu, tc lu m qua mt im ca tng cng c trong t hp my yu cu v thng xuyn nhc nh kp thi vic thc

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    hin m nn mi lp phi ng nh lm khi lm th nghim i vi mi loi t ln c ngun gc v t l thnh phn ht bit. Nu thc hin m nn khng ng bt k mt yu t no ca cng ngh m nn c trnh duyt khi lm th nghim buc phi lm li cho ng.

    - i vi mi lp phi o cao b mt lp bng my thy bnh lc san ri, lu s b xong ( cao ny k hiu l Htr) v lc thc hin m nn xong ng nh lm khi lm th nghim ( cao lc ny k hiu l Hs), t tnh ra tr s gim b dy lp sau khi m nn xong H:

    H = Htr - Hs; (1)

    C mi mt ct ngang cn xc nh H t 5 im n 10 im (ty b rng lp m nn) v ly tr s H trung bnh ca s im o i din cho mi mt ct ngang. Trn c mt on thi cng, c 20 m di o mt mt ct ngang. Tr s H trung bnh ca mi mt ct ngang trong mt on phi ln hn hoc bng tr s H xc nh c khi lm th nghim; nu H nh hn th phi tip tc m nn cho t.

    - i vi cng trnh quan trng v khi c nghi ngi v cht lng m nn, T vn gim st c th yu cu kim tra li khi lng th tch kh thc t t c sau thi cng ca lp t ln v so snh kt qu vi tr s khi lng th tch kh ln nht t c tng ng vi qui trnh cng ngh m nn lc lm th nghim hin trng trc , nu tr s thc t sau thi cng nh hn tr s lc lm th th phi c bin php m nn cho t c tr s lc lm th.

    Trong trng hp ny vic ly mu, th nghim xc nh khi lng th tch kh v m ti hin trng phi tun theo ASTM D5030-04 (p dng cho t ln c c ht ln nht trn 125 mm) hoc ASTM D 4914-99 (p dng cho t ln c Dmax = 75 mm n 125 mm). V tr v s im th nghim kim tra do T vn ch nh nhng khng nn nhiu hn mt v tr trn mt on thi cng di 50 m.

    Cch thc thit lp cc ch tiu ni trn dng kim tra cht lng m nn thng qua lm th nghim hin trng c ch dn ph lc C.

    + i vi cc lp p t ln , ngoi kim tra cht lng m nn cn phi kim tra bng cch quan st:

    - Mt lp t ln sau khi m nn phi lin kn khng c cc hc h (do cc to b bong bt);

    - Cc to l trn mt lp khng d b bong bt.

    7.3.12 Trong qu trnh p nn, nu quan st bng mt thy c nghi ngi v loi vt liu p, c th ly mu kim tra cc ch tiu qui nh ti 6.6.1 v kin quyt loi b cc vt liu p khng ph hp vi cc yu cu qui nh ti iu 5.

    7.4 Thi cng mi ta luy nn p.

    7.4.1 bo m cht lng m nn vng st gn mt ta luy, b rng p mi lp thn nn ng nn rng hn b rng thit k tng ng mi bn 15 cm n 20 cm.

    7.4.2 Trc khi tin hnh gia c ta luy theo thit k phi hon thin hnh dng mi ta luy (v dc v v bng phng), tin hnh m nn li b mt ta luy bng m ln vi s ln m ln t 3 ln/ im n 4 ln/ im v vt m phi chng ln nhau 20 cm.

    7.4.3 C 20 m di phi kim tra cht lng hon thin hnh dng mi ta luy ti mt mt ct ngang. Nu dc v bng phng mi ta luy cha t yu cu Bng 1 th phi sa cha cho t trc khi tin hnh cc gii php gia c.

    Ring trng hp nn p t ln mt ta luy phi khng c hin tng cc vin ln b bong bt (kim tra bng quan st).

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    7.4.4 Nu mi ta luy p c ph ngoi mt tng t hu c th tng ph ngoi ny cng phi ri v m nn tng lp nm ngang t di chn ta luy ln dn ng thi vi lp p thn nn ng pha trong.

    Trong qu trnh thi cng, lp ph ngoi ny cng phi c kim tra cht lng nh i vi lp p thn nn ng bn trong (xem ti 7.3.10). Vic hon thin hnh dng mi ta luy v kim tra cht lng hon thin trong qu trnh thi cng cng yu cu nh vi cc mi ta luy p t khc.

    7.4.5 Vic thi cng cc kt cu gia c phng h b mt ta luy nn c thc hin cng sm cng tt v phi thc hin ng h s thit k v cu to v v cc yu cu kim tra cht lng trong qu trnh thi cng.

    7.5 Thi cng nn p bng ct c lp p bao hai bn ta luy v nh nn.

    7.5.1 Vt liu p bao phi ph hp vi quy nh ti 5.5.

    7.5.2 Phi ri v m nn tng lp t p bao dc hai bn ng thi vi ri v m nn lp ct thn nn ng bn trong t di y nn p ln dn.

    7.5.3 Phi ri v m nn ring lp t p bao nh nn.

    7.5.4 Trong qu trnh thi cng p phi c bin php hn ch nc ma thm nhp, tch t trong phn thn nn p bng ct v phi b tr rnh xng c tm thi hoc tng m thot nc bng vi a k thut hoc cc bc thm ngang di y nn p thot nc tch t trong ct ra ngoi.

    7.5.5 Yu cu v cht lng v cch kim tra cht lng p bao c thc hin nh vi p t thn nn ng (qui nh ti 7.3.10). Yu cu v cht lng v cch kim tra cht lng thi cng mi ta luy p bao cng phi tun theo qui nh ti 7.4.1, 7.4.2 v 7.4.3.

    7.6 Thi cng p on tip gip vi cc cng trnh nhn to (cu, cng, tng chn...).

    7.6.1 Phm vi p on tip gip gia m cu hoc lng cng vi nn p lin k t nht phi b tr nh hnh 1; i vi cng trnh tng chn v cc cng trnh khc, phm vi p on tip gip theo bn v thit k.

    a, on ng u cu

    b, Hai bn cng (D: khu cng)

    Hnh 1: Phm vi p on tip gip

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    Trong phm vi p on tip gip phi dng cc vt liu c tnh thot nc tt, tnh nn ln nh nh t ln si cui, ct ln dm, ct ht va, ct ht th. Khng c dng t c tnh thot nc km v ct mn, trng hp khng c iu kin tm vt liu khc phi gia c cc loi t ny bng vt liu lin kt v c p (ti thiu l vi 5% xi mng hoc 10% vi). Khng c p bng cc loi phong ha v khng p ln ln cc loi vt liu khc nhau. Cng c th p bng tro bay, vt liu nh hoc b tng bt nhng phi trnh duyt kt qu nghin cu v lm th nghim trc khi thi cng i tr.

    7.6.2 Trc khi p on tip gip phi hon thnh tt cc lp phng nc thm vo thn m, thn tng chn... v cc lp phng nc thm ra t cng cng h thng thot nc dc v ngang sau cng trnh theo ng thit k. Nht thit phi nghim thu cc hng mc n du ni trn t yu cu mi c p.

    7.6.3 Trong mi trng hp p on tip gip phi ri v m nn tng lp dn t di ln vi b dy lp m nn ch nn t 10 cm n 20 cm (k c khi dng lu nng). Nu dng dng c m nn nh, b dy lp m nn ch nn di 10 cm.

    cht yu cu trong ton phm vi p on tip gip phi t 0,98 i vi ng cao tc, ng cp I, cp II v 0,95 i vi ng cc cp khc ng thi phi ln hn hoc bng cht m nn yu cu i vi cc b phn nn ng khc nhau nh qui nh Bng 2.

    Khng c lt bt k vng no khng c m nn k c cc vng st thnh vch cng trnh. Ti cc vng st thnh vch cng trnh phi dng m bn nng ln hn 100 KN hoc m rng din thi cng sau m din thi cng cho my m nn nng hot ng; vi ng cao tc c b rng nn ln c th cho lu nng lu theo hng ngang st thnh vch m.

    Ti cc ch lu hoc m bn khng thao tc c phi dng m chn ng bng tay t yu cu qui nh.

    Vic kim tra cht lng m nn cng phi thc hin tng lp theo cch qui nh ti 7.3.10.

    7.6.4 Nn ng thi thi cng phm vi p on tip gip v phm vi p cc phn t nn. p trong phm vi khu vc tc dng cng nn thc hin ng thi vi p khu vc tc dng trn on ng ni tip lin k.

    7.6.5 Trng hp p on tip gip bng t gia c hoc vt liu khc th phi tun th ch dn k thut trong h s thit k (k c cc ch tiu v phng php kim tra). Thi cng cc kt cu khc nh bn qu , gi k hoc ng cc cui bn qu ... nm trong phm vi p on tip gip phi tun theo cc ch dn v bn v thit k.

    8 Thi cng nn o

    8.1 Cng tc o.

    8.1.1 Phi thi cng o t trn xung, khng c o ty tin, khng c o khot hm ch.

    8.1.2 Trong qu trnh thi cng o phi c bin php bo m ta luy ang o lun n nh. o n gn mt ta luy v gn n cao nh nn thit k phi cn thn trnh o qu. Nu t d b ma lm xi mt th nn bo lu mt b dy di 20 cm n khi hon thin (hoc trc khi thi cng khu vc tc dng v kt cu o ng) mi gt nt cho n st mt ta luy v cao nh nn thit k.

    8.1.3 Trong qu trnh thi cng, nu pht hin iu kin a hnh a cht c sai khc vi thit k, phi kp thi xut cc thay i v dc ta luy, v cc bin php bo m n nh ta luy v c v v tr, kch thc rnh nh trn nh ta luy. Cc xut thay i phi c trnh duyt theo cc qui nh v qun l d n.

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    8.1.4 Trong qu trnh o, nu pht l tng hoc vt l nc ngm th phi ngng thi cng v xut, trnh duyt cc gii php x l. Trong khi ch x l phi thc hin ngay cc bin php thot nc tm thi, dn nc ngm thot ra khi phm vi thi cng hoc o ho h nc ngm, khng c nc ngm t do thm hoc chy trn lan.

    8.1.5 Sau khi o n cao thit k phi ly mu t trong phm vi khu vc tc dng th nghim cc ch tiu qui nh ti 6.6.2 v 6.6.3 quyt nh xem c cn thay t trong phm vi khu vc tc dng khng.

    8.1.6 Phi da vo iu kin a hnh, loi hnh mt ct ngang nn o, chiu di vn chuyn v hng vn chuyn t o chn my thi cng v phng n thi cng thch hp. My thi cng nn chn loi ph hp vi phm vi s dng an ton v kinh t ca chng (tham kho bng A-1 Ph lc A). Trn mt on nn o c th s dng phng n o sut c on tng lp t trn xung hoc o tng on trn mt phn hoc ton b trc ngang. Chn phng n thi cng phi kt hp bo m iu kin thot nc tt trong qu trnh o t nh qui nh ti 6.5.5 v bo m iu kin lm vic thun li cho xe my.

    8.2 Thi cng mi ta luy o.

    8.2.1 Mi khi o su c t 2 m n 3 m nn kim tra v chnh sa mt mi ta luy ngay cho ng v tr v dc (c bit l vi cc on nn o su).

    8.2.2 Phi loi tr ngay cc khi c lp hoc ri rc cn nm trn mi ta luy.

    8.2.3 Kim tra yu t hnh hc, bng phng ca mi ta luy phi c thc hin kp thi nh qui nh ti 8.2.1 v c lc trc khi tin hnh bt k bin php gia c no trn mt mi theo yu cu ti Bng 1. C 20 m di phi kim tra cht lng hon thin mi ta luy o ti mt mt ct ngang.

    8.2.4 Vic thi cng kt cu gia c phng h b mt ta luy o nn c thc hin cng sm cng tt (k c cc rnh nh) v phi thc hin ng theo h s v ch dn k thut thit k.

    8.3 t tha

    8.3.1 Trc khi thi cng phi kim tra thc a cc khu vc d kin cho t tha bo m chc chn rng vic t khng gy tc dng xu n cnh quan mi trng v khng vi phm qui hoch s dng t ca a phng nh qui nh ti 4.7.

    Khng c t tha trong phm vi t ai canh tc; khng c xung sng, sui lm cn tr dng chy gy xi l thm sng hoc sn dc pha di nn o v gy nhim dng chy pha h lu.

    8.3.2 t khng c to ra cc yu t tc ng xu n mc n nh ca bn thn nn ng: khng c t tha trn mi ta luy nn p, trn mi thin nhin di nn o ni c a cht xu hoc c mch nc ngm. Khng c dn ng trn phn ngoi l ng v trn nh ta luy o.

    8.3.3 Vic t tha nn tun theo cc quy nh sau:

    - Nn tp trung mt s khu vc c php , trnh vic ri rc ty tin;

    - m bo n nh, dc mi ta luy ng t tha khng nn dc hn 1:1,5, chiu cao khng nn cao qu 3 m. Ti ch nn ri v m nn to dc 2% trn mt ng t .

    8.4 Thi cng rnh thot nc.

    8.4.1 Trc khi thi cng phi xc nh v tr tim rnh t tim tuyn v phi cm cc tim rnh. Nn cm c cc v tr mp rnh bin.

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    8.4.2 Rnh bin lc u nn o nh hn kch thc thit k. Ch o gt hon thin rnh ng kch thc thit k sau khi hon thin nn ng (gt mui luyn nn v bt l xong). Trnh o rnh ln vo thn v ta luy nn ng.

    8.4.3 t o t rnh bin khng c ln l ng. t o t rnh nh c th p thnh b chn nc (con trch) pha di dc ngang v phi c m cn thn vi mi dc p c dc 1:1,5, mt trn nghing v rnh nh vi dc 2% n 4%. Mp ta luy con trch phi cch nh ta luy o ti thiu l 5 m.

    8.4.4 dc rnh nh tt c cc on nn di 5%, nu qu 3% th phi c bin php gia c rnh; nc t rnh nh khng c cho trc tip xung rnh bin hoc ging t hay ca cng m phi dn cho nc xung pha thng lu cch ca cng t nht 30 m thng qua dc nc hoc bc nc.

    8.4.5 Rnh xy v cc bc nc, dc nc phi xy bng ; mch va khng c rng qu 40 mm v y va.

    8.4.6 Cc rnh dc nc, bc nc bng b tng xi mng nn phn on di t 2,5 m n 5 m v bng xy nn phn on di 5 m n 10 m thi cng v phi chn khe ni gia cc on bng vt liu phng nc.

    8.4.7 ng mp b rnh bin phi song song vi tim ng. ng mp b ca tt c cc loi rnh cc on thng phi ngay thng, cc on rnh cong phi cong u, khng c gy khc, un ln ty tin c bit khi thi cng cc on ni tip rnh vi cc cng trnh thot nc khc, tuyn v mp rnh phi ni tip mt cch m thun.

    8.4.8 Trc v sau khi thi cng gia c rnh theo thit k, phi kim tra cc yu t hnh hc. Cch thc kim tra cht lng thi cng cc loi rnh v sai s cho php phi tun theo cc qui nh ti Bng 1.

    9 Thi cng nn ng na o, na p v nn ng ci to, nng cp m rng

    9.1 Thi cng nn ng na o, na p.

    9.1.1 Sau khi thi cng x l nn t nhin di y phn nn p theo cc qui nh ti 7.2 mi c bt u thi cng phn nn o. t o ra nu ph hp vi cc yu cu v vt liu p qui nh iu 5 th c th y xung phn nn p, san ri v m nn tng lp t di ln cao dn.

    9.1.2 Vic thi cng phn o v phn p cng phi tun theo cc qui nh ti iu 7 v iu 8.

    9.1.3 Phi c bit ch trng bin php bo m s ng u v sc chu ti trong phm vi khu vc tc dng gia phn nn o v phn nn p, cn thit phi thay t trong phm vi khu vc tc dng ca phn nn o tng ng vi phn p.

    9.2 Thi cng nn ci to nng cp m rng

    9.2.1 Phi da vo bn v thit k thc hin gn vic ph dn va, l ng c, cc trang thit b, bo hiu v phng h pha m rng nn ng; rnh xy phi c ph d khi xy, vt sch vt liu c v ri t m nn t cht qui nh tng ng.

    Khi lp cc rnh bin c phi lm trc cc rnh thot nc tm vic thot nc trn ng c khng b nh hng dn n gy tr ngi cho vic bo m giao thng trn ng hin c.

    9.2.2 Trc khi thi cng, phi lm cc cng trnh tm chn khng cho nc t bt k ngun no chy vo khu vc thi cng o hoc p m rng.

    9.2.3 X l y phn p m rng phi da vo h s thit k v tun theo cc qui nh ti 7.2

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    9.2.4 Trc khi p phn m rng phi gt b mi ta luy nn p c ht b dy lp hu c, sau to bc cp theo yu cu thit k ri mi c p tng lp t di ln. Khng c dng t o gt t mt mi ta luy nn ng c p phn nn p m rng mi.

    9.2.5 Lp di cng ca phn nn p m rng nn dng si, ct hoc dm p thnh mt tng m dy 30 cm. Nu mt phn nn p m rng b ngp nc hoc c iu kin a cht xu phi x l theo thit k.

    9.2.6 Vt liu p phn nn m rng nn s dng cng loi vi vt liu p nn c hoc chn loi vt liu c tnh nn ln thp.

    9.2.7 Thi cng phn nn o m rng phi tun theo cc qui nh ti iu 8.

    9.2.8 Trng hp ng va khai thc va thi cng ci to nng cp, m rng phi c cc bin php iu khin, khng ch bo m giao thng lun thng sut, an ton v thun li cho vic thi cng nn ng. Trong ma ma phi c bin php hn ch t ri vi trn mt ng ang khai thc v hn ch thi gian xe phi chy trc tip trn nn t mi thi cng (nn c gng lm mt ng sm).

    9.2.9 Khi phi h hoc tn cao c kt cu o ng c cn tun theo cc qui nh sau:

    - Chiu dy lp t kp gia kt cu o ng c v kt cu o ng mi khng c nh hn 50 cm.

    - Vt liu o b kt cu mt ng c c th c tn dng p nhng v tr thch hp nhng phi c chp thun bi t vn thit k.

    10 Thi cng hng mc phng h v gia c ta luy

    10.1 Quy nh chung

    10.1.1 Ch c thi cng cc cng trnh phng h v gia c trn cc mi ta luy chc chn n nh, khng c nguy c b nc ngm ph hoi, hon thin b mt v c kim tra nghim thu mt ta luy theo cc qui nh ti 7.4.3 hoc 8.2.3.

    10.1.2 Trc khi thi cng cn i chiu thit k vi iu kin a hnh, a cht, thy vn ti ch, nu thy khng thch hp cn xut thay i bin php phng h, gia c kp thi.

    10.2 Trng cy, c chng xi mi ta luy

    10.2.1 Phi chn ging, loi v thi tit thch hp vi iu kin a phng khi trng cy, c. Phi chm sc cho n lc cy, c sng (ti, bn phn...). Nc ti cy, c khng c ln du m v cc cht c a xt hoc kim.

    10.2.2 Khi trng c bng gieo ht phi xm t trc ri rc ht u v c bin php bo v ht khng b tri theo nc ma, lng ht khong 200 g cho 100 m2. Khi trng bng vng c phi c b dy vng t pha di t 5 cm n 10 cm, kch thc b mt vng t c c t 20 cm n 30 cm. Trc khi xp vng c phi xm mt su 3 cm n 5 cm v phi gm vng c vo mt ta luy bng cc inh tre di 15 cm n 20 cm.

    Vng c c th xp thnh hng song song vi mp ng, khong cch gia tim hai hng c khong 1,5 ln b rng vng c. Cng c th xp thnh vung cho vi mp ng 450, mi c kch c 1,2 m x 1,2 m, khong cch gia tm cc l 1,4 m.

    10.2.3 Vic trng v chm sc cc loi cy, c v trng c bng cc k thut c bit (phun ht ging bng my, trng trong cc lng bng vi a k thut... hoc phun bn cc vng c ln mt ta luy) phi tun theo cc ch dn ca thit k.

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    10.2.4 Khi thi cng trng cy, c mi taluy nn thc hin t di chn ln dn pha nh; mi ta luy o nn trng qu nh ta luy ti thiu 1,0 m.

    10.2.5 Kim tra cht lng trng cy, c

    - Din tch cy, c b cht khng c qu 10% v khng c vng cy c b cht thnh mng trn 1,0 m2;

    - B dy lp c trng nn di 10 cm;

    - Kim tra thi im su thng sau khi trng, nu khng t yu cu ni trn th phi trng b sung;

    - Vic trng cy, c trong cc khung b tng hoc cc xy gia c mi ta luy cng c kim tra theo ch tiu ni trn.

    10.3 Thi cng tng phng h bng xp khan v xy hoc xy vin b tng c

    10.3.1 Phi dng loi cng c cng chu nn ln hn 40 MPa (nu l b tng xi mng th cng nn c cng chu nn ln hn 20 MPa), khng c dng ang phong ha. Kt cu lp phng h (kt cu mng pha chn mi dc, kt cu lp m...) phi theo ng thit k.

    10.3.2 Tng phng h xp khan nn c phn chn mng xy va, c bit l trng hp phng h mi ta luy nn o c rnh bin di chn ta luy.

    10.3.3 Khe ni cc vin xp khan phi so le v phi c chm chn cht bng nh.

    10.3.4 Cng va xy phi ng nh yu cu thit k.

    10.3.5 Vic xy hoc vin b tng xi mng phi kt thc trc khi va bt u ninh kt v phi bo dng (ti nc) ngay khi va va ninh kt.

    Khe ni mch va xy phi so le v y va.

    10.3.6 Ch nn xy tng phng h sau khi nn ng ln t yu cu qui nh cc tiu chun thit k v thi cng nn p trn t yu hin hnh.

    10.3.7 Xy hoc b tng phi c khe co dn v phng ln cch nhau t 10 m n 15 m, b rng khe 20 mm n 30 mm. Phi l thot nc theo ng bn v thit k.

    10.3.8 Ti cc v tr ta luy c th ngp nc, mng chn khay ca tng phng h xy phi t su ti thiu 1,0 m di cao b xi. Nu o mng thy iu kin a cht xu, khc vi bn v thit k th phi xut bin php x l.

    Sau khi xy xong v nghim thu mng, phi p hon tr ngay bng vt liu nh yu cu thit k.

    10.3.9 Kim tra cht lng thi cng

    - Mt lp xp khan hoc lp xy phi bng phng. Cc khe ni (xp hoc xy va) khng c k h, phi so le, c chn cht, mch va phi y. Cc vin phi tip xc vi mt mi ta luy, khng c gi ln nhau;

    - Cch kim tra v cht lng tng xp khan phi t yu cu nh ti Bng 4, i vi tng xy ; phi t yu cu nh ti Bng 5 k c i vi xy vin b tng xi mng.

    Bng 4: Cch kim tra v tiu chun cht lng tng phng h xp khan

    Ni dung kim tra Sai s cho php so vi Cch kim tra

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    thit k

    B dy tng phng h 50 mm 100 m2 o kim tra ngu nhin bn v tr

    Cao mt tng phng h 30 mm Dng my thy bnh o ngu nhin nm iim cho mt on di 20 m

    bng phng mt tng phng h

    50 mm (khe h di thc 2 m) C 20 m di o nm v tr

    Bng 5: Cch kim tra v tiu chun cht lng tng phng h xy

    Ni dung kim tra Sai s cho php so vi thit k

    Cch kim tra

    Cng va Khng nh hn thit k C mt ca thi cng ly hai t mu th

    Cao

    Mt trn 20 mm My thy bnh o trc v sau khi xy. C 20 m di o nm v tr ngu nhin

    Mt y - 20 mm

    Kch thc trn mt ct ngang tng phng h

    30 mm C 20 m di o nm v tr ngu nhin

    bng phng mt tng phng h

    30 mm (khe h di thc 2 m)

    Mt on di 20 m o ngu nhin nm v tr bng thc 2 m

    10.4 Thi cng phng h ta luy bng cch

    10.4.1 Phi dng loi cng, chu nc tt, kh phong ha; kch c phi ty thuc chiu su nc ngp, tc dng chy v p lc sng v vo ta luy nhng ti thiu phi ln hn 300 mm.

    10.4.2 dc ca mi ta luy sau khi phi thoi hn gc ngh t nhin ca t. B dy tng phng h khng c nh hn 2 ln c ln nht.

    10.4.3 Nn chn ma nc cn thi cng, nn dng kch c nh ln vi c kch thc ln hn.

    10.4.4 Kim tra cht lng thi cng:

    - Kch c v loi phi ph hp vi thit k.

    - V tr trn mt bng, khu vc phi ph hp vi thit k (Sai s cho php l -20 cm so vi thit k), cao nh khng thp hn thit k, dc mi ta luy ng khng dc hn thit k.

    10.5 Thi cng tng chn cc loi v cc cng trnh chng khc.

    Thi cng cc loi cng trnh ny phi tun th cc quy nh trong ch dn k thut ca h s thit k (k c cch kim tra v ch dn kim tra cht lng thi cng).

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    11 An ton v bo v mi trng trong qu trnh thi cng nn ng

    11.1 Quy nh chung

    11.1.1 Trc khi thi cng phi nghin cu k cc iu kin a hnh, h s a cht, thy vn ti ch v d bo cc din bin thi tit (ma, bo...) c th xy ra c bin php d phng nhm bo v an ton cho ngi, xe my ti sn nh yu cu ti 4.6 v phi c cc bin php hn ch tc ng xu n mi trng nh yu cu ti 4.7.

    11.1.2 Cc bin php m bo an ton lao ng phi da vo cc vn bn php quy hin hnh hu quan v bo v sc khe, phng chng chy n, phng chng dch bnh. Cc bin php hn ch tc ng n mi trng phi da trn bo co nh gi tc ng mi trng vi cc ni dung chi tit quy nh cc vn bn php quy hin hnh i vi giai on thi cng cc d n; c bit nn ch trng iu tra cc tuyn ng ng ngm, ng dy in, cp quang ngm trong phm vi thi cng.

    11.1.3 Phi b tr cc bin bo r rng v c sc thu ht s ch nhc nh mi lc lng thi cng, dn c ln cn v ngi i qua phm vi thi cng c thc t bo v.

    11.2 Cc bin php bo m an ton thi cng.

    11.2.1 Phi c chiu sng nu thi cng v m. S dng mng in chung phi tun th cc quy nh ca ngnh in lc.

    11.2.2 Khi thi cng ng tm, cu tm phi b tr cnh bo, bin bo hoc ngi trc tip ch dn giao thng.

    11.2.3 Ngi tham gia thi cng phi c hun luyn trc v cc quy tc m bo an ton lao ng trong cng vic c th ca mnh v phi mc trang phc bo h lao ng khi vo hin trng thi cng. Ngi phi hp vi my phi trnh lm vic ngay trong phm vi my ang thao tc.

    11.2.4 Gia cc my cng thi cng phi ch trng gi mt khong cch an ton. My khng c i li st cc rnh, cc h mng, st mp ta luy v cc ch nn km n nh.

    11.2.5 My ch c o gn st cc thnh vch cch cng trnh nhn to mt khong bo v an ton cho cng trnh, khi o ln cn cc cng trnh ny cn t bin cnh bo.

    11.2.6 o h mng cng trnh hoc o cc ho thot nc phi c bin php m bo vch ho n nh (c mi dc hoc c c chng ...) ty theo iu kin a cht, thy vn v chiu su o. Nu o di chn mi taluy nn ng hoc mi dc thin nhin nn p dng bin php o cch qung xen k, o mt on v xy xong mng cng trnh hoc o mt on t ho, ng thot nc xong, lp li ri mi o v thi cng cc on xen k cn li. Nu o mng hoc h o su th phi t bin cnh bo, b tr hng ro phng h v phi theo di tnh trng bin ng ca b vch o c bin php x l kp thi, t o mng khng c nh hng n s n nh ca vch o.

    11.2.7 Lm vng vy chn nc thi cng mng cc cng trnh phng h di taluy p c ngp nc phi d bo mc nc ngp, d bo kh nng c ct chy, ct n d kin bin php phng.

    11.2.8 Dng thit b bng ti cc kiu hoc cc gi nng ko vt liu ln cao vn chuyn , phi b tr cng nhn chuyn nghip ch huy, cm s dng qu ti, cm dng bng ti ch ngi.

    Khi chuyn cm ngi lm vic ng, ngi di cc thit b nng vt liu ln cao.

    11.2.9 Khi thi cng xy lp cc tng phng h ta luy, cm i li trn phn mt dc va xy, khng c ln , vt liu hoc dng c t trn cao xung.

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    11.2.10 Khi dng cc my phun va, my hi p phi thng xuyn theo di ng h o p lc, nu c hin tng gia tng hoc chy bt bnh thng th phi ct in ngng my kim tra x l.

    11.2.11 Khi thi cng nn ng nu phi dng n bin php n mn th nht thit phi c thit k n mn v lp h chiu n mn (V tr t thuc n trn bnh , loi thuc, bin php gy n, thi gian gy n, phm vi cc c ly an ton cho ngi thi cng n mn, cho cng trng v cho dn c, cc ch dn khc v x l mi tnh hung c th xy ra khi thi cng n mn). Thi cng n mn phi tun theo cc quy nh sau:

    - Phi o to cc nhn vin chuyn nghip. Khi thi cng phi c phn cng v quy nh trch nhim r cho tng ngi.

    - Phi c cnh bo v hiu lnh phng trnh cho cng trng v dn c xung quanh, nhng ni c ngi i li phi b tr ngi canh gc v barie ngn chn.

    - Trc khi gy n phi c ngi chuyn trch kim tra thi cng mng li gy n.

    - Cc nhn vin lm cng tc lin quan n bo qun, vn chuyn, lp t v gy n khng c mc qun o c mang theo cc vt d gy ra tnh in.

    - Vt t gy n phi bo qun ring r, thng xuyn kim tra v loi b cc vt t km hoc suy gim cht lng. Phi thc hin ng cc qui nh khi nhp v xut vt t gy n v cc qui nh hin hnh khc v ct gi vt liu gy n.

    - L mn trnh t trc din vi ng i, ng dn in v cc nh ca cng trnh xung quanh. Cm lp t thuc n cc l mn c khng n.

    - Khi mn n, phi m s ting n kim tra xem c ph hp vi s l mn lp t khng. Nu pht hin mn cm, phi x l theo ch dn h chiu bn mn.

    - Thi cng n mn khng nn thc hin v m; gp ma, sm chp phi ngng thi cng v rt ht ngi ra khi phm vi thi cng.

    - Mn lp t phi cho n ngay trong cng mt ca cng tc.

    - Phi thn trng khi dn v sau khi gy n. Nu pht hin mn cm hoc v tr d ln th phi bo co v b tr cnh bo kp thi.

    11.3 Bo v mi trng.

    11.3.1 Phng nga nhim t, ngun nc v xi l t:

    - Phi c gng hn ch v rt ngn thi gian s dng t phc v thi cng.

    - Khng c ly t, khai thc ct, ty tin nh qui nh ti 4.7 v nhng ni c dng chy d gy xi l t.

    - Cc rnh thot nc tm thi trong qu trnh thi cng khng c cho chy ra rung vn, h ao khc.

    - Trong qu trnh thi cng phi b, chn lp ph liu, ph thi sinh hot ti cc ni c php ca chnh quyn a phng, c bit l ph thi c ln du m d gy nhim ngun nc.

    11.3.2 Phng nga nhim kh thi v ting n.

    - Phi c bin php hn ch ting n v chn ng do thi cng gy ra.

    - Phi trang b cho cn b cng nhn trc tip thi cng cc phng tin hn ch ting n.

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    - Phi c bin php hn ch ngun gy bi, kh thi, cho xe, my tham gia thi cng v vn chuyn t hoc vt liu, c bit l phi c bin php hn ch t ri vi khi vn chuyn.

    - Nn t bi t, cha vt liu cc loi pha cui gi so vi vng dn c sinh sng.

    11.3.3 Bo v sinh thi.

    - Phi c bin php bo v cc cy ci qu him ngay t trc khi thi cng.

    - Trong qu trnh thi cng cm ty tin cht ph cy ci v sn bn th rng.

    - Phi thc hin y cc quy nh ca nh nc v bo v ng vt hoang d v qu him.

    - Thi cng nn ng qua rng v vng cy ci rm rp phi c cc bin php phng chy rng v bo v rng theo quy nh ca php lut.

    11.3.4 Bo v di sn vn ha

    Phi tun th quy nh 4.8.

    12 Kim tra nghim thu

    12.1 Kim tra trc khi thi cng.

    12.1.1 Trc khi thi cng phi kim tra tt c cc ni dung qui nh ti iu 6; nu cha hon thnh ng cc quy nh bt k ni dung no th phi thc hin li, cho ng mi c thi cng.

    12.1.2 Phi c bit ch trng kim tra chnh xc v tr tuyn sau khi khi phc (qui nh ti 6.5.1 v 6.5.2), chnh xc ca vic nh v cc im c trng ca nn ng qui nh ti 6.5.6. Cch kim tra l dng cc my o c thng thng kim tra tt c cc mt ct ngang trong bn v thi cng chi tit.

    12.1.3 Vic kim tra t v vt liu xy dng nn ng phi c thc hin theo quy nh ti 6.6.

    12.2 Kim tra trong qu trnh thi cng.

    12.2.1 Kim tra cht lng thi cng nn p

    + Kim tra vic ly t p v s ph hp ca vt liu p theo cc quy nh ti 7.1, k c trng hp p on tip gip ln cn cc cng trnh nhn to, trng hp nn ct c p bao v trng hp p t ln . Thng thng vt liu p c kim tra t ch ly t nh quy nh ti 7.1.3. Tuy nhin sau khi ri v m nn nu c nghi ngi th c th cn c vo quy nh ti 7.3.12 tin hnh kim tra li, lc ny s mu v cc ch tiu kim tra c th tng thm nu thy cn thit.

    + Kim tra cht lng x l mt nn t nhin trc khi p quy nh ti 7.2.

    - Kim tra o bc lp t hu c, khng c st bt k ch no.

    - Kim tra vic to bc cp (qui nh ti 7.2.2 v 7.3.7): Kim tra ngu nhin kch thc bc mt s ch nghi ngi v nht thit phi c nh cp v lu ln mt bc cp.

    - Kim tra cht ca mt nn t nhin (ti 7.2.1), cht ca mt bc cp v cht p b cc ch trng theo quy nh ti 7.2.5.

    - Kim tra theo cc ch dn k thut h s thit k i vi cc trng hp qui nh ti 7.2.7.

    + Kim tra cht lng p theo cc quy nh ti 7.3.10 i vi trng hp p t v ti 7.3.11 i vi trng hp p t ln . Vic kim tra cht lng p thng thng ch thc hin trong qa trnh thi cng i vi tng lp t p, do vy phi a vo h s nghim thu cng trnh sau ny tt c cc bin bn nh gi cht lng tng lp.

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    + Kim tra cht lng thi cng mi taluy p theo quy nh ti 7.4

    12.2.2 Kim tra cht lng thi cng nn o.

    - Phi kim tra loi t v cc ch tiu lin quan trong phm vi khu vc tc dng ca nn o sau khi o n cao nn thit k theo quy nh ti 8.1.5, 6.6.1, 6.6.2 v 6.6.3.

    - Phi kim tra cht lng thi cng mi taluy o theo quy nh ti 8.2.

    - Kim tra vic t theo cc quy nh ti 8.3.

    12.2.3 Kim tra cht lng thi cng rnh thot nc v thi cng gia c rnh, vic kim tra c thc hin theo cc quy nh ti 8.4.8 kt hp vi vic quan st bng mt v o bng thc theo cc quy nh ti 8.4.4, 8.4.5 v 8.4.6.

    12.2.4 Kim tra cht lng thi cng cc hng mc gia c mi ta luy thng thng c thc hin theo cc quy nh ti 10.2 (trng c chng xi), ti 10.3.1 (tng phng h xp khan) v ti 10.4.4 (tng phng h xy va).

    12.2.5 Trong qu trnh thi cng phi da vo cc quy nh iu 11 thng xuyn kim tra vic bo m an ton thi cng v hn ch cc tc ng xu do thi cng gy ra i vi mi trng.

    12.3 Kim tra v nghim thu sau khi hon thnh nn ng.

    12.3.1 Sau khi hon thnh mt on nn ng v trc khi nghim thu on phi khi phc li v tr tuyn v cc mc cao ch yu phc v cho vic o c kim tra nghim thu v cng lm c s thi cng cc hng mc khc. Vic khi phc tuyn phi c thc hin theo cc quy nh ti 6.5.1 nhng trn cc on ng thng khong cch cc v tr khi phc c th tng ln 50 m.

    12.3.2 Trc khi nghim thu nh thu phi:

    - T kim tra cht lng cc hng mc thi cng theo cc cch qui nh ti 12.2 sa cha hon thin khim khuyt. Nu phi p b, b dy lp p b t nht phi l 10 cm (cn b t hn th phi xo xi pha di cho 10 cm). Vic b ph l phi m bo lin kt tt vi phn l p. Quan st bng mt, cc on nn ng hon thnh phi chuyn tip u n, khng li lm, khng gy khc k c v b rng v mi ta luy.

    - Nh thu cng phi chun b y v hon chnh h s nghim thu theo ng cc th tc v qun l d n. Trong c bit phi ch n cc bin bn kim tra nghim thu cc cng trnh n du v cc bin bn kim tra cht lng trong qu trnh thi cng.

    - Phi dn sch s hin trng thi cng theo yu cu ti iu 4, ti 11.3.1 v dn cc ng t tha vi phm quy nh ti 8.3.1

    12.3.3 Kim tra phc v cho vic nghim thu mt on nn ng phi c thc hin vi cc ni dung sau:

    - Kim tra cc bin bn thc hin trong qu trnh thi cng.

    - Kim tra cc yu t hnh hc vi cch kim tra tng ng qui nh ti Bng 1

    - Kim tra cht lng trng cy, c gia c mi ta luy theo quy nh ti 10.2.5 v kim tra tng phng h xp khan hoc xy va theo quy nh ti 10.3.9.

    Nu kt qu kim tra cho thy mt s ni dung cha t yu cu, phi yu cu nh thu b sung, sa cha cho n khi kim tra t mi ra vn bn nghim thu.

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    12.3.4 Trng hp c nghi ngi v cht lng vt liu p v cht lng m nn hoc cht lng mng cc hng mc n du th khi kim tra nghim thu c th thc hin li cc ni dung nh kim tra trong qu trnh thi cng qui nh ti 12.2 nhng phi c s chp thun ca ch u t hoc cc c quan c thm quyn khc.

    12.4 Kim tra nghim thu cc hng mc cng trnh c bit.

    i vi cc cng trnh hoc hng mc cng trnh nn ng khng qui nh trong tiu chun ny, vic kim tra nghim thu mi bc phi tun th cc quy nh ca ch dn k thut trong h s thit k.

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    Ph lc A

    (Tham kho)

    Chn my thi cng o p t

    Bng A.1: Phm vi s dng ca mt s loi my ch yu

    Loi my

    Phm vi s dng

    Cng tc chun b Cng tc o p

    t Cc cng tc

    khc

    My i

    - Lm ng tm. - n cy, nh gc cy. - Dy c, bc lp t hu c. - San to dc. - Lp h, mng rnh. - To bc cp trn sn dc.

    - o t v vn chuyn i di 120 m. - o t v y ln nn p cao di 3,5 m.

    - San m s b cc lp t ri (*) - H tr my cp khi xn t. - Ko my, ko xe b sa ly.

    My xc cc loi

    - Lm ng tm (my xc gu nghch).

    - o v t trong phm vi 5 m n 10 m ( ln t chuyn i).

    - o ho. - o t di nc (gu dy). - Vt bn.

    My cp chuyn

    - Ry c. - o lp t hu c v p t.

    - o t v t chuyn i (c ly thch hp t 100 m n 1000 m ty dung tch gu). - T ri t thnh lp p.

    - m nn s b sau khi o t.

    My san t hnh

    - Ry c. - Bc t hu c. - nh bc cp.

    - Ly t thng u p nn cao di 75 cm. - o nn su di 60 cm.

    - Gt phng taluy, o v p tng t cao 2 m. - o rnh thot nc. - San phng to dc ngang mui luyn.

    My xi

    - Cy xi mt, nn c. - n cy, nh gc cy, ry cc cy nh.

    - Xi trc cc loi t cng to thun li cho cc my o t khc.

    (*) S dng cho cng vic ny khng tn dng c cng sut my nn khng kinh t

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    Ph lc B

    (Tham kho)

    Chn phng tin m nn t nn ng

    B I. Ty thuc loi t, c th tham kho chn t hp thit b m nn khi thi cng nn p ng t theo Bng B.1 di y:

    Bng B.1: Chn phng tin m nn ty loi vt liu p

    Loi vt liu p

    Loi

    phng tin

    m nn

    t ht mn

    t ct t si

    cui t ht

    th Phm vi s dng

    Lu 2 bnh, bnh nhn: 6 tn n 8 tn

    + + + + Dng lu s b to phng

    Lu 3 bnh, bnh nhn: 12 tn n 18 tn

    + + + - Rt thng s dng

    Lu bnh lp: 25 tn n 50 tn

    + + + + Rt thng s dng

    Lu chn cu + - o o C th dng cho t ct ln st, ln bi t dnh

    Lu chn ng - + + + Rt thng s dng

    Lu chn ng c vu + + + + Hay dng khi lu t ht mn c m cao

    Lu chn ng y tay - + + o Dng m nn cc ch cht hp

    m bn chn ng - + + -

    Dng ni cht hp, loi bn m nng 800 kG mi dng m t ht th c

    m chn ng y tay

    + + + - Dng ni cht hp

    My i, my cp chuyn

    + + + + Dng san phng v lu s b

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    Bng B.1: Chn phng tin m nn ty loi vt liu p (tip theo)

    CH THCH:

    1. Cc k hiu nh du trong mi c ngha sau:

    + thch dng; - khng thch dng nhng c th dng; o: khng thch dng

    2. Tn cc loi t tng ng vi phn loi TCVN 5729:2012

    3. Khi dng lu chn cu, lu chn ng, lu chn ng c vu phi c lu bnh nhn phi hp lm phng

    B II. B dy lp t ri trc khi m nn tng ng vi cc loi lu (tham kho)

    - Lu chn cu 6 tn n 8 tn: 30 cm

    - Lu chn ng 10 tn n 12 tn: 40 cm

    - Lu chn ng 15 tn n 18 tn: 50 cm

    - Lu bnh nhn 8 tn n 12 tn: 20 cm n 25 cm

    - Lu bnh nhn 12 tn n 15 tn: 25 cm n 30 cm

    - Lu bnh lp 12 tn n 20 tn : 20 cm n 30 cm

    - Lu bnh lp 40 tn n 50 tn: 50 cm n 60cm

    - m chn ng y tay: 20 cm

    - m th cng: 20 cm

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    Ph lc C

    (Qui nh)

    Cch thit lp cc ch tiu kim sot cht lng m nn i vi lp t ln thng qua on thi cng th nghim

    C I. Nguyn l.

    Trong tiu chun ny vic kim tra cht lng m nn lp t ln trc ht vn da vo khi lng th tch kh ( cht) ln nht max c th t c tng ng vi t hp my v cng ngh m nn thch hp nht thc c, thc lm trn on thi cng th nghim hin trng, tc l ly tr s max xc nh hin trng ni trn lm cht tiu chun thay cho cht tiu chun xut pht t th nghim m nn trong phng th nghim. cht max hin trng ny s thay i ty thuc ngun gc, thnh phn ht ca t ln , ty thuc t hp my m nn, b dy lp ri, m, cng m nn (s lt lu m) v tc lu. T mi tng quan gia cht hin trng max ly lm tiu chun vi cc yu t thay i ni trn khi kt thc vic thi cng th nghim phi a ra c cc ch tiu c trng cho cng ngh m nn la chn cng vi mt ch tiu gin tip khc, l tr s gim b dy lp m nn H da vo chng kim sot qu trnh thi cng m nn v kim tra nghim thu cht lng m nn nh qui nh ti 7.3.11.

    C II. Xc nh cht tiu chun hin trng max.

    Cc ni dung phi thc hin:

    1. La chn t hp my m nn thch hp v thc c trong iu kin c th ca d n: Ngoi cc loi lu nh, lu va dng lu s b ban u v lu hon thin cui cng, my lu ch o nn c l lu chn ng nng t 15 tn tr ln (nu khng c th phi dng lu chn ng nng nht c th huy ng c).

    2. Ri th nghim v b tr on thi cng th nghim.

    a. Vt liu t ln ri th nghim phi cng loi vi vt liu p i tr v ngun gc v thnh phn ht.

    b. Nn b tr ri th ti thiu vi hai b dy ri khc nhau.

    - Mt b dy tng ng vi b dy ti thiu khong t 1,65 n 1,8 ln c ht ln nht Dmax c trong vt liu p ( sau khi m nn cht cn khong 1,5Dmax).

    - Mt b dy bng khong 40 cm nu dng lu chn ng t 15 tn tr ln hoc bng khong 32 cm nu dng lu chn ng t 10 tn n 12 tn.

    - Tng ng vi mi b dy nn cho m thay i ti thiu 3 mc trong khong t 0,95 Wo n 1,05 Wo, vi Wo y l m tt nht ca vt liu p sau khi loi tr cc c ht trn 19 mm (th nghim m nn tiu chun vi ci to trong phng th nghim theo 22TCN 333-06.

    - Khi ri vt liu p phi ch quy nh ti 7.3.2. Nh vy on thi cng th nghim phi gm t nht su on ngn.

    CH THCH: Vic b tr on th nghim c th gm nhiu on ngn hn (hon ton do t vn quyt nh) da theo cc iu kin thc t ti ch (cho thay i nhiu b dy v m hn).

    3. Thit k s lu, trnh t lu v tc lu.

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    a. Phi da vo cc quy nh ti 7.3 thit k bao gm c cc bc lu s b, lu cht v lu hon thin lp mt.

    b. Tc lu cht nn khng ch di 4 km/h.

    c. Son tho ch dn k thut ri v m nn cho thi cng th nghim (yu cu phi tht t m chi tit).

    4. Thi cng th nghim v ly mu th nghim.

    a. Ri v m nn theo ng ch dn k thut son tho.

    b. Sau khi lu cht bng lu chn ng c 6 ln/im, 8 ln/im, 10 ln/imphi thc hin th nghim xc nh khi lng th tch kh v m ca lp m nn ti hin trng theo ASTM D5030-04 hoc ASTM D4914-99 nh qui nh ti 7.3.11.

    c. Sau khi lu s b, trc khi lu cht phi o cao b mt lp v sau khi lu cht 6 ln/im, 8 ln/im, 10 ln/imphi o li cao b mt lp cng 1 ch tnh ra tr s gim b dy lp H theo quy nh ti 7.3.11, t xc nh ra H trung bnh ca c mt ct ngang kim tra.

    5. Chn cht tiu chun hin trng max.

    Da vo kt qu th nghim thu c v cc th th hin s bin i khi lng th tch kh vi s lt lu v m cho mi b dy lp ri th, t c th thy xu th tng chm dn ca cht khi s lt lu tng ln v c th xc nh c mt cng ngh m nn c li nht. Tuy nhin vn phi chn tr s khi lng th tch kh ln nht tuyt i trong ton b tp kt qu thu c lm cht tiu chun hin trng max. Tr s ny chnh l cht ln nht c th t c trong iu kin thc t, vi cc t hp my thc c v vi quy trnh cng ngh m nn thch hp nht.

    6. Xc nh cc ch tiu kim tra khc.

    a. T tr s max s xc nh c cc thng s ca cng ngh m nn tng ng: b dy ri trc khi m nn, m khi m nn, s lt v tc lu cc bc (c bit l bc lu cht). ng thi cng xc nh c tr s gim b dy lp H tng ng cho mi mt ct ngang kim tra, y chnh l cc ch tiu dng kim sot v kim tra cht lng m nn i vi tng lp thi cng.

    b. C th c trng hp cc thng s cng ngh m nn khc nhau nhng cng t c max xp x nhau (chng hn nh trng hp b dy lp ri nh lu t ln hn vn cho max xp x bng trng hp lu lp dy nhng nhiu ln hn, hoc c th mt s m thch hp th hiu qu m nn cao hn). Lc ny c th chn mt quy trnh cng ngh m nn c li hn v kinh t thi cng i tr.

    Cc tr s max c xem l xp x nhau khi chng sai khc nhau khng qa 0,02 max.

    c. Nu c thit b v c cc quan h tng quan tin cy th nn kim tra tr s CBR ca lp t ln sau khi m nn t max bng cc th nghim hin trng nh o CBR hin trng suy ra tr s CBR tng ng. Khi kt qu o cho tr s CBR t yu cu Bng 3 th vic la chn max lm cht tiu chun cng c c s chc chn hn.

    7. Son tho quy trnh cng ngh m nn t ln ng dng chnh thc cho thi cng i tr. Quy trnh phi th hin y cc thng s ca cng ngh m nn c p dng, cc ch tiu phi kim sot cht trong qu trnh thi cng v cc ch tiu kim tra cht lng sau khi hon thnh m nn mi lp.

    8. Kim nghim quy trnh m nn.

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    Trong t ng dng u tin khi thi cng i tr cn kim nghim s ng n v thch hp ca quy trnh m nn bng cch lm th nghim xc nh li khi lng th tch kh theo ASTM ni trn sau khi m nn xong mt lp ng nh quy trnh v so kt qu xc nh c vi tr s max rt ra t thi cng th nghim. Nu c s chnh lch gia chng qu 0,02 max th phi tm nguyn nhn v c s chnh sa cn thit i vi quy trnh.

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    Ph lc D

    (Qui nh)

    Phng php th nghim xc nh tng lng mui d ha tan trong t.

    D.1 Nguyn l

    D.1.1 Khi chng cn dung dch lc (pha ch theo qui nh ti mc D.1.2), cc mui d ha tan c kt tinh li, tip em sy kh 1000C 1050C ri cn th s xc nh c tng lng mui d ha tan trong t.

    D.1.2 Pha ch dung dch lc

    1. Cn 200g t trong khng kh (t nghin nh ry qua mt ry 1 mm nht ht r cy v xc hu c ri sy kh 1050C v ngui trong khng kh) cho vo chai thy tinh 500 ml c ming hp.

    2. Ly 500 ml nc ct un si cn m vo chai c t ni trn (nc ct phi un si thi kh CO2). Nt cht nt chai v lc u trong 30 pht.

    D.2 Dng c th nghim v ha cht

    D.2.1 Dng c th nghim

    1. Cc m 50 ml

    2. ng ht 50 ml

    3. Bnh ht m

    4. T sy

    5. Cn vi chnh xc 0,0002 g

    D.2.2 Ha cht cn c

    Dung dch H2O2 10% v nc ct. Nc ct phi tinh khit khng ha ln cc ion l nh Cl-, Ca+, Fe+++, Mg++.

    D.3 Trnh t th nghim

    D.3.1 Ht 50 ml (hoc 25 ml) dung dch lc (qui nh ti mc D.1.2) cho vo cc m ( bit khi lng cc). t cc ln bp cch thy v chng cho n khi cn kh. Nu cn c mu vng hay en tc l t c ln hu c ha tan, lc nh vi git dung dch H2O2 10% cho t u ri li em chng cn. Khi no cn c mu trng th ngng vic x l (ngng nh) bng H2O2.

    D.3.2 Cho cc mu v t sy v sy nhit 1000C 1050C trong 1 h n 2 h ri lm ngui n nhit bnh thng trong bnh ht m v em cn khi lng mu.

    Sau tip tc sy nhit 1000C 1050C trong vng 0,5 h ngui v cn cho n khi khi lng cc mu khng thay i na l c.

    D.4 Tnh ton tng lng mui d ha tan trong t A c tnh theo biu thc (2)

    KVV

    GGGA ..

    1

    01 g/100g t kh (2)

    Trong :

    G0 khi lng cc khng (g);

    G1 khi lng cc v cn sau khi sy kh (g);

    G khi lng ton b mu t dng pha dung dch lc (g);

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    V th tch ton b dung dch lc (ml);

    V1 th tch dung dch lc em th nghim (ml);

    K h s kh bit ca t xc nh theo (3).

    WK

    100100

    (3)

    Trong :

    W (%) l m ca mu t ngui trong khng kh ( m t kh trong khng kh). m ny xc nh t mu t ly trc khi cho vo chai thy tinh im 1 mc D.1.2

    __________________________________________