B NNG NGHIP V PHT TRIN NNG THN

TIU CHUN K THUT THIT K BIN

(Ban hnh theo Quyt nh s 1613/Q-BNN-KHCN ngy 09/ 7/2012

ca B trng B Nng nghip v Pht trin nng thn)

H NI - 2012

LI NI U

Tiu chun c bin son t 14TCN 130-2002 Hng dn thit k bin v Tiu chun k thut p dng cho chng trnh cng c, bo v v nng cp bin t Qung Ninh n Qung Nam (Ban hnh km theo Quyt nh s 57/Q-BNN-KHCN ngy 08 thng 01 nm 2010), c chnh sa, cp nht v b sung t mt s kt qu nghin cu ca cc ti khoa hc cng ngh giai on II thuc Chng trnh khoa hc cng ngh phc v xy dng bin v cng trnh thy li vng ca sng ven bin v cc tiu chun khc c lin quan.

Tiu chun do T son tho Hng dn thit k bin (km theo Quyt nh s 1522/Q-BNN-KHCN ngy 07 thng 6 nm 2010 ca B trng B Nng nghip v Pht trin nng thn) bin son c s h tr ca Trng i hc Thy li v Trng i hc Cng ngh Delft, H Lan; Cc Qun l iu v Phng chng lt bo, V Khoa hc Cng ngh v Mi trng ngh; B Nng nghip v Pht trin Nng thn ban hnh.

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1. Phm vi p dng

1.1 Tiu chun k thut ny quy nh v cc tiu ch, ch s k thut v cc yu cu khi thit k, thm nh, ph duyt cc d n u t xy dng thuc Chng trnh cng c, bo v v nng cp bin c Th tng Chnh ph ph duyt ti Quyt nh s 58/2006/Q-TTg ngy 14 thng 3 nm 2006 i vi cc tnh ven bin t Qung Ninh n Qung Nam v Quyt nh s 667/Q-TTg ngy 27 thng 5 nm 2009 i vi cc tnh ven bin t Qung Ngi n Kin Giang.

1.2 Khi p dng, ngoi cc quy nh trong tiu chun ny, cn phi tun th cc quy nh trong cc vn bn quy phm php lut khc c lin quan.

1.3 Tiu chun ny c th c s dng nh ti liu tham kho cho cng trnh khc c iu kin k thut tng t.

2. Ti liu vin dn

Cc ti liu vin dn sau l cn thit cho vic 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 bn mi nht, bao gm c cc sa i (nu c).

TCVN 8481- 2010, Quy nh thnh phn, khi lng kho st a hnh i vi cng trnh iu;

TCVN 8477: 2010, Quy nh thnh phn, khi lng kho st a cht trong cc giai on lp d n v thit k cng trnh thu li;

TCVN 8216:2009, Thit k p t m nn;

TCVN 4253:2012, Cng trnh thy li - Nn cc cng trnh thy cng - Yu cu thit k; TCVN 8166:2012, Cng trnh thy li Yu cu k thut thi cng bng bin php m nn nh;

TCVN 9165:2012, Cng trnh thy li - Yu cu k thut p ;

3. Ti liu c bn lm cn c thit k

3.1 Ti liu a hnh

- Thnh phn, khi lng kho st a hnh: p dng Tiu chun TCVN 8481- 2010 quy nh thnh phn, khi lng kho st a hnh i vi cng trnh iu.

- Ngoi ra cn p dng cc quy nh sau:

+ Ti liu thu thp c thi gian khng qu 05 nm i vi vng bi trc n nh v khng qu 01 nm i vi vng bi ang bi hoc xi;

+ Phm vi o c ti thiu 100m t tim tuyn d kin v pha ng v 100m t ng mp nc v pha bin. Trong trng hp trng rng ngp mn, cn kho st phm vi v pha bin ti thiu l 500m.

+ tnh ton truyn sng t vng nc su vo v tr chn cng trnh, i vi mi tuyn c chiu di nh hn hoc bng 10 km cn kho st 01 mt ct ngang i din (vung gc vi hng trung bnh ca tuyn ) t mp nc ti khu vc ngoi khi c su 10m.

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+ i vi vng b bin xi, cn thu thp thm ti liu lch s v din bin ca ng b t nht l 20 nm so vi thi im lp d n;

+ Trng hp vng t d kin tuyn i qua l vng t yu phn b rng (vng m ly) c th s dng phng php khng nh xem xt tng th a hnh, a mo.

3.2 Ti liu a cht

- Thnh phn, khi lng kho st a cht p dng theo Tiu chun ngnh TCVN 8477: 2010 quy nh thnh phn, khi lng kho st a cht trong cc giai on lp d n v thit k cng trnh thu li.

- i vi cng trnh t trn nn t yu thnh phn khi lng kho st a cht tham kho thm cc tiu chun nh: 22 TCN 262-2000 Quy trnh kho st thit k nn ng t p trn t yu; 22 TCN 260-2000 Quy trnh kho st a cht cc cng trnh ng thy (trong c cng trnh k b, k chn sng, k chng sa bi, tng chn.vv...).

- Ngoi ra, cn cn c iu kin thc t cng trnh xc nh thnh phn khi lng kho st a cht ph hp, trnh cp c thm quyn ph duyt.

3.3 Ti liu kh tng, thy vn, hi vn

Thu thp v phn tch ti liu v thy triu, bo, nc dng do bo, dng ven, vn chuyn bn ct, sng, dng chy l vng ca sng v cc thin tai khc trong khu vc d n. Thi gian thu thp ti liu ti thiu 20 nm so vi thi im lp d n. Trng hp cha c ti liu cn tin hnh o c, b sung s liu v s dng m hnh tnh ton ph hp m phng v nh gi xu th bin ng.

3.4. Ti liu dn sinh, kinh t v mi trng

- Thu thp, thng k ti liu v dn s, kinh t v mi trng hin trng;

- Quy hoch v k hoach pht trin kinh t - x hi trong tng lai.

4. Tiu chun an ton v phn cp

4.1. Tiu chun an ton

Tiu chun an ton (TCAT) c xc nh trn c s kt qu bi ton phn tch ti u xt ti mc thit hi v ngi, c s h tng, ti sn trong vng c bo v v tng mc u t. TCAT c th hin bng chu k lp li (nm), quy nh ti Bng 1.

4.2. Xc nh cp

- bin c phn lm 5 cp: cp I, cp II, cp III, cp IV v cp V.

- Cp c xc nh theo hng dn phn cp ban hnh km theo vn bn s 4116/BNN-TCTL ngy 13 thng 12 nm 2010 ca B Nng nghip v Pht trin nng thn.

- Trng hp khng ti liu xc nh cp theo hng dn ti vn bn s 4116/BNN-TCTL th c th xc nh cp theo tiu chun an ton ti Bng 1.

- Cp la chn cui cng l cp c gi tr bng hoc nh hn theo cc tiu ch nu trn v

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- Trong trng hp tuyn kt hp vi cc vai tr quan trng khc nh vn an ninh, quc phng hoc thuc vng c c th ring v cc mt kinh t, x hi th cn c nhng quy nh ring trong vic la chn cp i vi tng trng hp c th.

Bng 1. Tiu chun an ton v phn cp

Vng Tiu chun an ton (chu k lp li:nm) Cp

Vng th, cng nghip pht trin*:

- Din tch bo v > 100.000 ha

- Dn s > 200.000 ngi

150

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Vng nng thn c nng nghip pht trin, c quy hoch khu th, khu cng nghip:

- Din tch bo v: t 50.000 n 100.000 ha

- Dn s: t 100.000 n 200.000 ngi

100

II

Vng nng thn, nng nghip pht trin:

- Din tch bo v: t 10.000 n 50.000 ha

- Dn s: t 50.000 n 100.000 ngi

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III

Vng nng thn, nng nghip pht trin trung bnh:

- Din tch bo v: t 5.000 n 10.000 ha

- Dn s: t 10.000 n 50.000 ngi

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IV

Vng nng thn, nng nghip chm pht trin:

- Din tch bo v: < 5.000 ha

- Dn s : < 10.000 ngi

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V

GHI CH:

-(*): Khu cng nghip, nng nghip pht trin l da trn t l c cu kinh t trong vng c bo v. Nu t l

cng nghip ln hn th thuc vng cng nghip pht trin v ngc li.

- Khi s dng Bng 1, trc ht phi xp vng c bo v thuc loi vng thnh th hay nng thn, cng

nghip hay nng nghiptheo tiu ch vng sau xem xt hai tiu ch (din tch, dn s) xc nh TCAT.

Trng hp vng c bo v ch t 1 tiu ch th h xung 1 mc. Vic phn vng xt phi cp n

quy hoch v k hoch pht trin kinh t - x hi n 2020 v tm nhn n 2050.

- Cc tuyn b bao thit k vi chu k lp li nh hn 10 nm c xc nh l cc b bao tm hoc quy

phc v thi cng.

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5. Tuyn

5.1. Yu cu chung

- Ph hp vi quy hoch tng th;

- Cn c iu kin a hnh, a cht;

- nh gi din bin b bin, bi bin v ca sng;

- An ton, thun li trong xy dng, qun l v duy tr, pht trin cy chn sng trc ;

- Bo v cc di tch vn ho, lch s v a gii hnh chnh;

- Kt hp vi ng giao thng ven bin (nu ph hp);

- Ph hp vi cc gii php thch ng do nh hng ca bin i kh hu;

- m bo quy nh v nh gi tc ng mi trng.

5.2. Yu cu v v tr tuyn

- i qua vng c a th cao, a cht nn tng i tt;

- Ni tip thng thun v m bo n nh i vi cc cng trnh c;

- Thun li cho vic b tr cc cng trnh ph tr;

- Khng nh hng n thot l v cng trnh chnh tr ca sng (i vi ca sng);

- p ng yu cu i vi cc hot ng bn vng ca bn cng, bi tm, khu du lch, di tch lch s v danh lam thng cnh;

- i vi tuyn kt hp vi h thng giao thng v an ninh quc phng cn phi tun theo cc quy nh khc ca ngnh giao thng v quc phng;

- Tn dng ti a cc cn ct t nhin, i ni, cng trnh c khp kn tuyn , p ng yu cu kinh t - k thut ca tuyn ;

- So snh hiu qu ca 02 n 03 phng n tuyn la chn v tr t hiu qu tng hp tt nht;

- i vi tuyn quan trng cn tin hnh th nghim m hnh thu lc xc nh v tr tuyn thch hp.

5.3. Yu cu v hnh dng tuyn

5.3.1. i vi tuyn mi

- Hnh dng mt bng tuyn nn trnh gp khc, gim thiu ti a s tp trung nng lng sng cc b; ng thi nn trnh vung gc vi hng gi thnh hnh; thng qua so snh v khi lng cng trnh v tng mc u t quyt nh dng tuyn ph hp;

- Trong trng hp phi b tr tuyn cong, cn c cc bin php gim sng hoc tng cng sc chng ca khu vc cong;

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- Khng to ra im xung yu ni ni tip vi cc cng trnh ln cn v khng nh hng n cc vng t lin quan.

5.3.2 i vi tuyn hin c

Trng hp thit k nng cp tuyn hin c, cn phi xem xt cc yu cu nu mc (5.3.1) iu chnh cc b tuyn cho ph hp.

5.4. Thit k tuyn vng bi thay i

5.4.1.Tuyn vng bi bi

5.4.1.1. Yu cu chung

- Ph hp vi quy hoch h thng knh mng thu li, h thng ngn v cng thot nc trong khu vc c bo v, h thng giao thng phc v thi cng v khai thc

- c xc nh trn c s kt qu nghin cu v quy lut bi trong vng quai v cc yu t nh hng khc nh iu kin thu ng lc vng ni tip, sng, dng bn ct ven b, s mt cn bng ti ct vng ln cn, d bo xu th pht trin ca vng bi trong tng lai;

- Thun li trong thi cng, c bit l cng tc hp long , tiu thot ng, bi p t mi, ci to th nhng (thau chua, ra mn), c cu cy trng, quy trnh khai thc v bo v mi trng.

5.4.1.2. i vi trng hp quai ln bin

- Trn c s so snh v kinh t - k thut cc phng n la chn cao trnh bi ph hp, nu quai ln bin khi bi bi qu cao th vic khai thc bi sau khi quai gp kh khn, nht l vi mc ch m rng t nng nghip; nu quai khi bi bi cn qu thp th mc ri ro ln;

- Cao trnh thch hp nht tin hnh quai khi bi bi l ra cao trnh tng ng vi mc nc bin trung bnh;

- C th tin hnh quai vng bi c cao thp hn mc nc bin trung bnh, sau dng cc bin php k thut to nhanh qu trnh bi lng cho vng bi trong t mc tiu khai thc.

5.4.1.3. Cc tuyn ngn vng

Tuyn ngn vng c b tr trong tuyn chnh chia ton vng thnh cc v mi thnh nhiu mnh, thch hp vi iu kin t nhin v yu cu khai thc ca tng khu vc.

5.4.2. Tuyn vng bi bin xi

5.4.2.1. Yu cu chung

- i vi vng bi bin, b bin ang b xi, tuyn thng b ph hoi do tc ng trc tip ca sng vo thn, mi gy st st. Cn nghin cu k xu th din bin ca ng b, qu trnh h thp bi, c ch v nguyn nhn gy xi, cc yu t nh hng khc quyt nh phng n tuyn thch hp;

- Xem xt phng n tuyn cn gn lin vi vic nh gi kh nng tin hnh cc bin php chng xi, gy bi, n nh bi v b bin trc quyt nh;

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Khi cha c bin php khng ch c hin tng b, bi bin xi th tuyn phi c quy m v v tr thch hp; ngoi tuyn chnh, cn xem xt b tr thm tuyn d phng, kt hp vi cc bin php phi cng trnh gim tn tht trong trng hp tuyn chnh b ph hoi.

5.4.2.2. Tuyn chnh

Theo yu cu cc mc 5.1. v 5.2. cn xt n cc yu t c th ca hin tng bin ln la chn v tr tuyn chnh:

- Nm pha trong v tr sng v ln u (cch mt chiu di sng thit k).

- Song song vi ng mp nc khi triu kit (mc nc triu ng vi tn sut 95 %).

5.4.2.3. Tuyn d phng

- Khong cch gia tuyn d phng v chnh t nht bng 02 ln chiu di sng thit k.

- Gia hai tuyn chnh v d phng nn b tr cc ngn, khong cch gia cc tuyn ngn nn bng 03 n 04 ln khong cch gia hai .

- Kt hp giao thng v cu h .

6. Xc nh cc tham s hi vn

Cc yu t c trng iu kin bin hi vn chnh phc v cng tc thit k bin bao gm: mc nc thit k, cc tham s sng khu vc nc su v ti chn cng trnh tng ng vi tn sut thit k.

6.1. Mc nc thit k

Mc nc thit k (MNTK) l mc nc tng hp bao gm t hp mc nc triu thin vn v cc thnh phn nc dng do cc yu t khc to ra tng ng theo tn sut thit k.

6.1.1. trc din vi bin

Cc thnh phn chnh xc nh MNTK cho trc din bin gm: t hp mc nc triu thin vn v chiu cao nc dng do bo ng vi tn sut thit k v nh hng ca nc bin dng do bin i kh hu (nu c xt n). Cng thc tng qut xc nh MNTK nh sau:

Ztk,p = ZTB + (Atr+ Hnd)p (1)

Trong :

Ztk,p - Mc nc thit k bin ng vi tn sut thit k P% (m);

ZTB - Mc nc bin trung bnh ti khu vc d n quy v cao lc a (m);

Hnd - Chiu cao nc dng do bo (m);

Atr - Bin triu thin vn trn mc nc bin trung bnh;

(Atr+ Hnd)p- T hp mc nc triu thin vn v chiu cao nc dng do bo tng ng vi tn sut thit k P%.

T cng thc tng qut (1), MNTK c tnh sn cho cc v tr dc b bin theo cc tn sut thit

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k khc nhau v th hin bng cc ng tn sut mc nc tng hp tra cu ti Ph lc A. Khi s dng cc ng tn sut mc nc tng hp ti Ph lc A cn lu :

- Cn c TCAT quy nh ti Bng 1 xc nh chu k lp li mc nc thit k cho ton khu vc d n;

- Nu v tr cn xc nh mc nc thit k khng trng vi v tr tnh sn th c php ni suy gia hai v tr lin k;

- Khi xt n nh hng ca nc bin dng (NBD), MNTK thit k c xc nh bng tng gi tr ca mc nc thit k tra t ng tn sut tng hp cng thm gi tr d bo gia tng mc nc bin trung bnh do nh hng ca nc bin dng (ZNBD) v c xc nh theo cng thc:

Ztk,p = MNTKptra + ZNBD (2)

Trong :

MNTKptra - Mc nc bin tng ng vi tn sut P(%) tra theo ng tn sut mc nc tng hp ti Ph lc A.

ZNBD - Tr s gia tng mc nc bin trung bnh do nh hng ca nc bin dng, c xc nh nh sau:

ZNBD = Tct*RNBD (3)

Trong :

RNBD - Tc dng nc bin trung bnh (m/nm) theo kch bn NBD trung bnh quy nh bi B Ti Nguyn & Mi trng.

TCT - Tui th cng trnh d kin xy dng (nm); TCT c xc nh cn c vo tui th ca cng trnh v c quy nh bi cc c quan quyt nh u t v cc vn bn quy phm, php lut lin quan. Tui th ca c xc nh da vo cp v c quy nh ti Bng 2.

Bng 2. Quy nh v tui th ca cng trnh vnh cu

Cp Tui th (nm)

I-II 100

III-IV 50

V 20

V d: Tc dng nc bin trung bnh vng bin min Bc nc ta l 0,006 m/nm. H thng c thit k bo v vng th thuc loi cng trnh cp III c tui th l 50 nm. Gi tr gia tng mc nc bin trung bnh do nh hng ca nc bin dng trong trng hp ny l:

ZNBD = 50 (nm) x 0,006 (m/nm)= 0.3 m.

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6.1.2. bao quanh vng ca sng v m ph

Vic xc nh MNTK i vi bao quanh vng ca sng, m ph, cn phi k thm yu t nc dnh do nh hng kt hp ca nc l trong sng ra v nc pha bin truyn vo. Trong trng hp ny, cn phi s dng m hnh thy lc mt chiu xc nh mc nc kt hp ca hai yu t sng-bin ti v tr d kin xy dng cng trnh. iu kin bin cho m hnh thy lc mt chiu bao gm: Bin pha bin l mc nc pha bin tng ng vi tn sut thit k, xc nh theo Mc 6.1.1; bin pha sng l mc nc v lu lng l trong sng ng vi tn sut thit k.

6.2. Tham s sng thit k

6.2.1. Ti vng nc su (sng ngoi khi)

Tham s sng nc su bao gm: chiu cao sng c ngha v chu k sng (Hs, Tm) tng ng vi tn sut thit k v gc sng ti 0 ti khu vc nc su c nh hng trc tip n khu vc xy dng d n.

- Chiu cao sng v chu k sng thit k ti khu vc nc su c tnh ton sn cho tng vng dc theo ng b v c tra cu ti Ph lc B. Trong cn xc nh:

+ Vng bin ngoi khi nh hng trc tip n khu vc d n;

+ Chu k lp li hoc tn sut thit k;

+ Tra bng xc nh chiu cao v chu k sng thit k.

- Hng sng ti ti khu vc nc su l gc to bi gia phng php tuyn ng b v hng sng chnh ti khu vc d n. Trong thit k bin thng thng la chn trng hp bt li nht 0=00 (khng ), tng ng vi trng hp sng ti i vung gc (chnh din) vi on ng b.

6.2.2. Ti chn cng trnh

Chiu cao sng s dng trong cc tnh ton thit k mt ct ngang (nh sng leo, sng trn, n nh kt cu bo v mi, vv) l chiu cao sng ti c ngha Hs c xc nh ti v tr chn cng trnh do sng tng ng vi tn sut thit k ti khu vc nc su truyn vo (gi tt l sng thit k ti chn cng trnh).

Sng thit k ti chn cng trnh c xc nh bng cch truyn sng thit k t khu vc nc su vo n v tr xem xt.

- V tr chn cng trnh: c xc nh l v tr pha bin theo phng vung gc vi hng ng b, cch ng mp nc mt khong t L/2 n L0/4 theo phng vung gc vi ng b v pha bin.

Trong :

+ L: chiu di sng cc b ti chn cng trnh;

+ L0: chiu di sng vng nc su;

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+ ng mp nc: L giao tuyn gia mt nc bin ti mc nc bin trung bnh vi mt bi trc hoc mt mi ;

- Tnh ton truyn sng: Sng truyn t khu vc nc su vo v tr chn cng trnh tri qua cc qu trnh gim nng lng sng do hiu ng nc nng, ma st y, phn x, nhiu x v sng . Khuyn ngh thit k s dng m hnh truyn sng mt chiu SWAN - 1D do trng i hc Cng ngh Delft, H Lan cung cp phn tch truyn sng v xc nh cc tham s sng thit k ti v tr chn cng trnh. Hng dn s dng m hnh SWAN 1D ti Ph lc H.

Tham s sng nc su thit k tra t cc ng tn sut sng nc su ti cc v tr vng b dc b bin, tra Ph lc B nh quy nh ti mc 6.2.1.

Ngoi ra, trong Ph lc B tnh sn kt qu cc gi tr sng thit k ti chn cng trnh cho cc v tr dc b bin. C th s dng cc gi tr ny tham kho, so snh hoc tnh ton trong giai on thit k c s.

Chiu cao sng thit k la chn cui cng m bo ln hn hoc bng gi tr chiu cao sng gii hn su, c xc nh theo cng thc kinh nghim sau:

Hs = ahct (4)

Trong :

a - H s kinh nghim, bng 0,5;

hct - su nc ng vi MNTK ti v tr chn cng trnh.

6.2.3. Tnh ton sng khi c rng ngp mn

Rng ngp mn vi h thng r, tn cy s tiu tn mt phn nng lng khi sng i qua. Sau khi sng truyn qua rng ngp mn, chiu cao sng s b suy gim. Tuy nhin, khi xc nh gim sng trong thit k bin, rng ngp mn cn phi p ng y cc iu kin bt buc sau:

- Rng ngp mn tn ti;

- Trng thi v cht lng rng ngp mn lun m bo n nh;

Chiu cao sng k n s trit gim do c rng ngp mn xc nh theo cng thc:

Hs = Kt. (1+).Hs,k (5) Trong :

Hs (m): Chiu cao sng thit k ti v tr cng trnh c xt n nh hng ca rng ngp mn.

Hs,k: Chiu cao sng thit k ti v tr cng trnh khi khng c rng ngp mn.

Kt: H s trit gim sng (xc nh theo Hnh 1)

= (0,1 n 0,3): H s k n sai s v m hnh (rng tha 0,1; rng trung bnh 0,2; rng dy 0,3).

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H s gim sng Kt ph thuc vo chiu rng ca ai rng ngp mn (x) v trng thi ca rng ngp mn. Mt khc, mi trng thi rng ngp mn li c c trng bi mt gi tr ca tham s gim sng (r).

Mi tng quan gia Kt v r th hin qua cng thc:

( ) rxtK x e= (6)

T kt qu kho st thc t v phn tch, xc nh c gi tr tham s gim sng (r) i vi cc trng thi rng ngp mn ti Bng 3.

Bng 3. Tham s gim sng (r)

Trng thi RNM Tham s gim sng r

Dy

Trung bnh

Tha

0.010

0.007

0.004

Quan h v gi tr gia chiu rng ai rng ngp mn v h s gim sng c biu th ti Hnh 1.

Hnh 1. Quan h chiu rng ai rng ngp mn v h s gim sng

i vi rng dy, s dng ng s 1, rng trung bnh: ng s 2, rng tha: ng s 3.

Trng thi rng ph thuc mt , tn che ca mi loi rng (ph thuc vo chiu cao, ng knh tn, s cnh/cy...). Rng c chia thnh 3 trng thi: dy, trung bnh v tha ti Bng 4:

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Bng 4. Trng thi rng ngp mn ng vi mt v tn che

tn che rng (%) Mt

(cy/ha) 100 95 90 85 80 75

20.000 Dy Dy

16.000 Dy Dy Dy

12.000 Dy Dy Trung bnh Trung bnh

8.000 Trung bnh Trung bnh Trung bnh Trung bnh Trung bnh

4.000 Trung bnh Trung bnh Trung bnh Trung bnh Trung bnh Tha

3.000 Trung bnh Trung bnh Trung bnh Trung bnh Tha Tha

2.000 Trung bnh Trung bnh Trung bnh Trung bnh Tha Tha

1.500 Trung bnh Trung bnh Trung bnh Tha Tha Tha

1.000 Trung bnh Trung bnh Trung bnh Tha Tha Tha

GHI CH:

Mt (N): s cy trn mt hecta.

tn che (TC): t l (%) gia tng din tch hnh chiu cc tn cy trn b mt nm ngang v din tch mt

t.

7. Thit k mt ct

7.1. Yu cu thit k mt ct

- Thit k mt ct i vi tuyn mi, cng c, nng cp tuyn c v cc hng mc lin quan phi m bo cng trnh an ton, n nh vi iu kin bin thit k.

- Bo m yu cu v k thut - kinh t i vi mc tiu chnh v p ng yu cu ca cc mc tiu pht trin kinh t - x hi khc trong vng d n.

- Cc yu t chnh cn xem xt khi thit k mt ct gm: La chn mt ct, tnh ton xc nh cao trnh nh , thn v nn , dc mi , tnh ton n nh

7.2. Mt ct c trng

Mt ct c trng bin thng c 03 loi chnh:

- mi nghing;

- tng ng;

- hn hp (trn nghing di ng hoc trn ng di nghing).

Vic chn loi mt ct ph hp cn cn c vo iu kin a hnh, a cht, thu hi vn, vt liu xy

15

dng, iu kin thi cng v yu cu s dng phn tch v quyt nh.

Mt s v d minh ho mt ct ngang bin ti Hnh 2 (tham kho).

m=2~3

1

32

4

5

6

Ph a bin

ph a N G

s m t c t b in d n g t n g n g

N n

1. M t 2. N n c bc phong ha

4. Trng c m i

3. t dp thn 5.Tng6. Lng th chng xi7. Cy chn sng

7

s mt ct bin b tr c hai pha

Nn

132

m=2~3

m=2~3 m=3~5

m=3~54 5

6

78

Pha binpha NG

1. Mt 2. C pha ng3. C pha bin4. Rnh tiu

6. Lng th chng xi7. Mi pha ng8. Mi pha bin

9 10

5. Chn khay 9. Nn c bc phong ha10. t p thn 11. Cy chn sng

11

m=3~5

14

m=2~3

2 3

5

6

7

8

9

s mt ct bin dng mi nghingPha binpha NG

Nn

1. Mt 2. Nn c bc phong ha 6. Lp lt3. t dp thn 4. Trng c mi

7. Chn khay8. Lng th chng xi

5. Gia c mi pha bin 9. Mng tiu nc10. Cy chn sng

10

m=3~5

s mt ct bin bo v 3 mtPha binpha NG

14

m=2~3

2 3

5

6

7

8

9

10

Nn

1. Mt 2. Nn c bc phong ha 6. Lp lt3. t thn 4. Gia c mi pha ng

7. Chn khay8. Lng th chng xi

5. Gia c mi pha bin 9. Mng tiu nc10. Thit b thot nc11. Cy chn sng

11

16

m=3~5

m=2~3

1

2 31. M t 2. N n c bc phong ha

4

6. Lp lt

5

67

8

9

10

s m t ct bin d n g h n h pPha bin

ph a N G

3. t thn 4. Trng c m i

7. Tng8. K hi Tetrapod

5. G ia c m i pha bin 9. Lng th chng xi10. Cy chn sng

N n

Hnh 2. Mt s mt ct bin c trng

7.3. Xc nh cc tham s thit k mt ct

7.3.1. Cao trnh nh

7.3.1.1. Cng thc tng qut

Zp = Ztk,p + Hlk + a (7)

Trong :

Zp - Cao trnh nh thit k (m);

Ztk,p - Mc nc thit k (MNTK);

Hlk - cao lu khng;

a - Tr s gia tng cao.

Tnh ton xc nh cc thnh phn trong cng thc (7) nh sau:

7.3.1.2. Mc nc thit k (Ztk,p): MNTK xc nh theo mc 6.1.

7.3.1.3. cao lu khng (Hlk)

a) trc din vi bin, khng cho php sng trn

cao lu khng (Hlk) c xc nh l khong chiu cao t MNTK n v tr m sng thit k leo trn mi , quy nh l chiu cao sng leo 2% do sng thit k gy ra Rsl2%, p (c ngha l cho php 2% s con sng thit k c trn qua nh , tng ng vi lu lng sng trn rt nh v c coi nh sng khng trn qua nh ). cao lu khng c xc nh theo cng thc:

Hlk = Rsl 2%, p (8)

Trong :

Hlk - cao lu khng ca nh trn MNTK.

Rsl 2%, p - Chiu cao sng leo, c xc nh ti Ph lc C.

17

b) trc din vi bin, cho php sng trn

Trng hp ny, cc yu t tc ng tng t nh Mc a, tuy nhin cao lu khng (Hlk) c xc nh cao khng ch lu lng sng trn qua nh nh hn lu lng sng trn cho php thit k [q] (l/s/m) v c xc nh theo cng thc:

Hlk = Rc,q (9)

Rc,q - cao lu khng ca nh trn MNTK khng ch lu lng sng trn khng ln hn gi tr lu lng sng trn cho php [q] (l/s/m) trong iu kin thit k. cao lu khng theo tiu chun sng trn c xc nh ti Ph lc C.

[q] -Lu lng trn cho php thit k (l/s/m) tra theo Bng 5. Gi tr [q] ph thuc vo bn chng xi ca cc hnh thc bo v nh , mi pha ng v mc thit hi ca khu vc pha ng do nc trn vo.

Bng 5. Quan h lu lng trn cho php qua nh v gii php bo v pha ng

Hnh thc v cht lng lp bo v mi pha ng Lu lng trn cho php

[q] (l/s/m)

Khng c bo v 0,1

Trng c cht lng tt, ng nht 10

Bng lt khan, c tng lc 20

Bng cu kin b tng lp ghp c tng lc 30

LU :

- Trng hp s dng loi kt cu khc, n v t vn phi chng minh v bn v cp lu lng trn

cho php la chn hoc c tin hnh nghin cu thng qua m hnh th nghim khng nh c tin

cy trc khi p dng.

- Trong trng hp thit k chu sng trn, ty theo ln ca lu lng sng trn cho php, thit k

cn phi xem xt mc chp nhn thit hi ca khu vc pha ng do nh hng ca nc trn qua nh

v b tr cc gii php thu, tiu nc trn ph hp.

7.3.1.4 Xc nh cao trnh nh khi kt hp cho php thot l ni ng

i vi nhng d n c nhim v va phi p ng yu cu ngn mn, va phi p ng yu thot l chnh v t pha ni ng ra bin/ca sng, cao trnh nh c xc nh nh sau:

Z = Ztk + a (10)

Trong : Ztk v a gii thch mc 7.3.1.1

Trng hp bao quanh vng c yu cu thoat l ni ng (hay cho php thot l ni ng) th cn phi gia c 3 mt bo m bn chng xi do nc trn qua i vi chn , mi pha bin, mt v mi pha ng, tham kho Hnh 3.

18

Trong trng hp ny cn c bit lu rng khi c h thng s ngn cn kh nng thot l t nhin ca vung c nbo v. V vy, yu cu bt buc khi b tr thit k tuyn l phi tnh ton tng lng nc l ni ng cn tiu thot v b tr h thng thu, gom, tiu thot nc l ni ng tng ng vi quy m tuyn d kin xy dng.

Hnh 3. Mt ct bo v ba mt

Phn ln phi gia c 3 mt l cc tuyn ven m ph, ven ca sng min Trung (t Qung bnh n Bnh thun).

7.3.1.5 Xc nh tr s gia tng cao

Tr s gia tng cao c xc nh theo cp , tra Bng 6.

Bng 6. Tr s gia tng cao ca bin

Cp I II III IV V

Tr s gia tng cao a (m) 0,6 0,5 0,4 0,3 0,2

GHI CH:

Tr s gia tng cao trn cha bao gm cao ln ban u, ln c kt thn, nn v mc nc

bin dng phi ng ph do nh hng ca bin i kh hu.

7.3.2. Tnh ton kch thc, kt cu mt ct

7.3.2.1. Mt

a) Chiu rng: Chiu rng mt c quy nh theo cp , tra Bng 7.

Bng 7. Chiu rng mt theo cp cng trnh

Cp I II III IV V

Chiu rng mt B (m) 6 8 6 5 4 3

Trng hp mt kt hp lm ng giao thng, ng du lch hoc ng phc v cc ngnh kinh t khc th chiu rng mt c th m rng v phi ph hp v quy hoch, c c quan c thm quyn quyt nh.

b) Kt cu mt

19

- Trng hp khng c tng nh: Mt nh cn dc v mt pha hoc hai pha; b tr g an ton hai bn vi chiu cao t 0,2 0,3 m, phn on vi khong cch t 0,5 1,0 m m bo an ton cho cc hot ng trn mt v b tr h thng thot nc v mi pha ng.

- Trng hp c tng nh:

+ Ch la chn gii php tng nh trong trng hp tuyn vng d n b hn ch bi vic m rng mt ct ngang so vi cao trnh nh thit k.

+ Chiu cao tng tnh t mt tr ln khng cao qu 1,0 m v phi b tr khe ln, khong cch gia cc khe ln t 10 m n 20 m. Mng tng nh phi c lp vi kt cu bo v mi ; cao trnh y tng nh b tr cao hn mc nc thit k; tng nh cn c tnh ton n nh theo cc tiu chun hin hnh.

+ Cao y tng nh phi t cao hn mc nc thit k.

+ nh tng c th t mp pha trong hoc pha ngoi ca mt ty theo yu cu k thut v mc ch s dng mt . Trng hp b tr tng nh pha trong, mt c tc dng nh mt thm gim sng leo hoc sng trn. Trng hp mt kt hp ng du lch th tng nh phi b tr pha ngoi.

i vi mi, nu kt hp lm ng giao thng cao tc th nn b tr ng c pha ng hoc chn pha ng va tng n nh cho , va m bo giao thng khi c bo v va to iu kin nng cao thch ng vi nh hng ca bin i kh hu khi cn thit. Cp v kt cu ng tun theo cc tiu chun k thut v ng giao thng (tham kho TCVN 4054-2005).

7.3.2.2. Thn

a) Vt liu t p

- Tn dng ti a t ln cn cng trnh. i vi t ng cht, nn chn t st c hm lng st 15% n 30%, ch s do t 10% n 20%, khng cha tp cht. m t khi p khng nn vt qu 3% m ti u.

- Khng nn dng t bn bi tch, t st c hm lng nc t nhin cao v t l ht st qu ln, t trng n, t c tnh phn tn p . Trong trng hp phi s dng th cn c gii php k thut ph hp.

- Nu ngun t p ch c ct ht ri, thnh phn ht mn nh hn 25%, th phi c lp bc bo v (c th s dng lp t tht vi chiu dy khng nh hn 0,5m).

b) cht ca thn

i vi t c tnh dnh: ,

max

,

d

dscK

= (11) Trong :

Kc - cht thit k.

ds - Dung trng kh thit k ca t thn .

20

max - Dung trng kh cc i, c xc nh trong phng th nghim.

i vi t khng c tnh dnh: minmax

max

eeee

K dsds = (12)

Trong :

Kds - cht tng i thit k.

eds - H s rng cht thit k.

emax. - H s rng cc i tiu chun.

emin - H s rng cc tiu tiu chun.

cht thn bng t quy nh trong Bng 8.

Bng 8. Quy nh cht thn bng t

Cp I II v III IV v V

Kc 0,94 0,92 0,90

Kds 0,65 0,62 0,60

c) Nn v gii php k thut x l nn t yu

Nn phi bo m n nh (ng sut v bin dng, thm, ..) di tc dng ca cc loi ti trng tc ng v dng thm. Trng hp nn i qua vng t yu cn thit k gii php x l ph hp nh dng b phn p, thay nn t yu, s dng vi a k thut gia c nn hoc mt s gii php khc. Tnh ton thit k, gia s nn phi ph hp tiu chun, quy chun k thut quc gia hin hnh.

7.3.2.3. Mi

a) dc mi

dc mi m = cotg, vi l gc gia mi v ng nm ngang, c xc nh thng qua tnh ton n nh, c xt n bin php thi cng, kt cu gia c mi v yu cu s dng.

Thng thng ly m = 2,0 n 3,0 cho mi pha ng v m = 3,0 n 5,0 cho mi pha bin i vi c p bng t.

b) C gim sng pha bin

Yu cu k thut i vi c pha bin - thm gim sng, xem quy nh ti mc 7.3.5.3.

c) C pha ng

Khi c chiu cao ln hn 6m, dc mi m < 3,0 v yu cu giao thng c th b tr c v tr cch nh t 2m n 3m, chiu rng ca c ty thuc vo yu cu giao thng, nhng khng nh hn 5m. Thng mi pha di thoi hn mi pha trn c.

d) Chn pha ng

21

Thit k ng hnh lang chn phc v dn sinh, chng vi phm theo quy nh ca Lut iu, chiu rng hnh lang khng nh hn 5,0 m. Thng thng hnh lang chn pha ng c trng c chng xi. Trng hp cho php sng trn qua nh i vi sng trn thit k th gia c hnh lang chn pha ng kt hp vi thit k h thng thot nc trn qua nh .

H thng tiu thot nc trn qua nh bao gm cc rnh tiu nc dc, ngang; rnh dc thng c b tr mi, c, chn ; rnh ngang c b tr vung gc vi tim v cch nhau khong 50m. Kt cu bng b tng, gch xy hoc xy v.v kch thc v dc y ca rnh cn tnh ton trong trng hp lu lng sng trn ln hn 10 (l/s/m). Cc trng hp cn li b tr theo kinh nghim.

Knh thu nc sng trn, nc ma phi c b tr c lp, khng kt ni vi h thng knh tiu, ti trong ng, m bo khng xm nhp mn vo khu vc dn c, nng nghip, nui trng thy sn.

e) Chn pha bin

Chn pha bin cng l chn k bo v mi pha bin c th hin mc 7.3.5.4.

f) Cng trnh ct qua thn

Cng trnh ct qua thn phi thit k ring theo cc quy chun, tiu chun chuyn ngnh lin quan i vi tng loi cng trnh (cng, cu, trn, u thuyn). c bit ch x l ni tip gia thn v cng trnh, m bo an ton cho v cng trnh.

7.3.3. Tnh ton n nh

7.3.3.1. Ni dung tnh ton

- n nh chng trt mi ;

- n nh dng tng ng.

- Ln thn v nn .

7.3.3.2. Tnh ton n nh chng trt mi

- Chn mt ct tnh ton: ty theo c im ca tuyn , la chn mt s mt ct c tnh cht i din tnh ton n nh.

- Cc trng hp tnh ton

+ Trng hp c bn:

Tnh cho mi pha ng khi mc nc pha bin l MNTK, mc nc pha ng l mc nc thp nht (nu c);

Tnh cho mi pha bin: Mc nc pha bin rt nhanh t MNTK ti mc nc thp; b qua p lc sng ln mi pha bin.

+ Trng hp c bit: Mi pha ng v pha bin ang trong thi k thi cng, chu ti trng thit k.

22

- Phng php tnh ton: Theo tiu chun Thit k p t m nn TCVN 8216:2009 v cc quy chun, tiu chun k thut c lin quan.

- H s an ton chng trt K: c quy nh trong Bng 9.

Bng 9. H s an ton n nh chng trt cho mi

Cp T hp ti trng I II III IV V

C bn 1,30 1,25 1,20 1,15 1,10

c bit 1,20 1,15 1,10 1,05 1,05

- i vi p trn nn t yu s dng h s an ton chung cho cc cp cng trnh, tnh ton n nh theo trng thi cn bng gii hn vi ti trng tnh ton tiu chun v t nn dng sc khng ct tiu chun.

+ Tnh ton cho trng hp vn hnh lu di: K min = 1,4

+ Tnh ton cho trng hp thi cng: K min = 1,2

7.3.3.3 n nh dng tng ng

Cn tnh ton n nh chng trt phng; n nh chng lt; n nh ca t nn v n nh chng trt tng th.

a) n nh chng trt phng

+) Trng hp khng c lc dnh kt trn mt trt

H s n nh chng trt phng ca tng theo mt y lp tip xc:

Kat = (G+g).f + PE

p (13)

Trong :

G - Hp lc theo phng thng ng tc dng ln y tng (kN);

g - Trng lng vt liu ca lp m v khi phn p trong phm vi y tng (kN);

f - H s ma st: H s ma st theo mt tnh ton, ly theo Bng 10.

PE - p lc t b ng trn mt EE (kN);

P - Hp lc theo phng ngang tc dng ln y tng (kN);

23

Bng 10. H s ma st

Vt liu mt tip gip tng - nn H s ma st f

B tng v b tng 0,55

xy v xy 0,65

hc v hc 0,70

B tng v hc (b mt sa phng bng dm) 0,60

xy v hc (b mt sa phng bng dm) 0,65

v nn ct th, ct mn 0,50 0,60

v nn ct bt 0,40

v nn t ct 0,35 0,50

v nn st, st 0,30 0,45

+ Trng hp c lc dnh kt trn mt trt

H s n nh chng trt theo theo mt y lp m nh sau:

p

PEACtggGKs

+++= 00)( (14)

Trong :

o - Gc ma st gia y tng v nn; Co - Lc dnh kt n v trn mt trt;

A - Din tch y mt trt.

- H s an ton chng trt phng K:

+ i vi cc cng trnh b tng hoc xy c y tip xc vi nn phi nham thch: h s an ton chng trt phng quy nh trong Bng 11.

Bng 11. H s an ton n nh chng trut trn nn phi nham thch

Cp cng trnh

T hp ti trng I II III IV V

C bn 1,35 1,30 1,25 1,20 1,15

c bit 1,20 1,15 1,10 1,05 1,05

+ i vi cc cng trnh b tng hoc xy c y tip xc vi nn nham thch: h s an ton chng trt phng quy nh trong Bng 12.

24

Bng 12. H s an ton n nh chng trt trn nn nham thch

Cp cng trnh

T hp ti trng I II III IV V

C bn 1,15 1,10 1,10 1,05 1,05

c bit 1,10 1,05 1,05 1,00 1,00

b) n nh chng lt

Kim tra n nh lt ca tng v pha bin theo s tnh ton n nh dng tng ng (Hnh 4). Tnh ton n nh ca tng theo nguyn l ca tng chn t.

KHI T P

Tng ng

Hnh 4. S tnh ton n nh dng tng ng

H s n nh chng lt thn tng: G

Cat M

MK = (15)

Trong :

Kat - H s an ton n nh chng lt tnh ton ly bng h s an ton n nh cho php tra theo Bng 13.

MC - M men chng lt, tnh ton vi tm lt B trng hp mc nc pha bin thp v mc nc ngm pha ng cao; tm lt C trng hp ang thi cng, cha p t pha lng tng v mc nc pha bin l MNTK.

MG - M men gy lt.

Bng 13. H s an ton n nh chng lt

Cp cng trnh

T hp ti trng I II III IV V

C bn 1,6 1,5 1,5 1,3 1,3

c bit 1,4 1,3 1,3 1,2 1,2

25

GHI CH:

- T hp ti trng c bn l ti trng trong iu kin cng trnh lm vic bnh thng.

- T hp ti trng c bit l ti trng trong iu kin thi cng hoc khi c ng t.

- Cc gi tr h s an ton thit k khng c vt qu 20% i vi iu kin ti trng c bn v 10%

trong iu kin ti trng c bit.

7.3.4. Tnh ton ln

Phi xc nh ln tng cng ca thn v nn v tr ng tim dc v cc v tr cn thit khc cc mt ct i din cho cc on .

Ln nn bao gm 2 thnh phn chnh: ln ban u v ln c kt. Ln ban u l ln gy ra ngay sau khi gia ti. Ln c kt l ln gy ra do tc dng ca ti trng ngoi theo thi gian.

7.3.4.1. Tnh ton ln ban u

Tr s ln ban u Si c tnh ton theo cng thc (16)

E

BPSi)1( 2 = (16)

Trong :

P - p lc phn b u trn nn bin, (KN/m2).

B - Kch thc cnh ngn ca nn , (m).

- H s Poisson ca t (i vi t bo ho, = 0,5). E - Mun n hi ca t nn (KN/m2), xc nh thng qua th nghm ct khng thot nc 3 trc hoc th nghim nn n trc.

- H s nh hng, c th tham kho tr s trong Bng 14. Bng 14. H s nh hng

Tr s i vi nn c tnh do T l di rng

ca nn L/B im gia

im gc

Trung bnh ton nn

Tr s i vi nn cng trung bnh ton nn

2 1,53 0,77 1,30

3 1,78 0,89 1,52

5 2,11 1,05 1,83

10 2,58 1,29 2,25

100 4,0 2,0 3,70

Hi nh hn so vi tr s ca nn c tnh do

Khi khng c s liu v tr s E, ln ban u c th tnh theo cng thc (17)

26

oi SS

=31

41

(17)

So - Tng gi tr ln khi cc bn khng chuyn dch ra ngoi na, sau khi hon tt cht ti.

7.3.4.2. Tnh ton ln c kt

Gi tr ln c kt Sc tnh ton theo cng thc (18)

+== j

j

jjjc he

eeSS

1

21

1 (18)

Trong :

e 1j - h s rng khi nn n nh di tc dng ca trng lc ca lp t th j.

e 2j - h s rng khi nn n nh di tc dng ca ng lc t l ca lp t th j v ng lc ph gia.

hj - Chiu dy lp t th j, (m).

Sj - Lng nn p ca lp t th j (m).

i vi p trn nn t yu th tnh ht cc loi ln bao gm cc ln tc thi, c kt s cp v ln th cp, phng php tnh tham kho sch chuyn ngnh.

i vi p trn nn t yu thi gian tnh ln bng khong thi gian t khi thi cng xong n thi im nng cp nh k, khong thi gian ny do ch u t quyt nh (khng nn di 15 nm).

ln cho php theo thi gian i vi cng trnh trn nn t yu nh sau Bng 15: Bng 15. ln cho php

V tr on p trn t yu

Gn m cu Ch c cng di Cc on nn p thng thng

10cm 20cm 30cm

7.3.5. Thit k k bo v mi

K bo v mi bin thng c gi l k bin. Kt cu k bin bao gm ba phn: thn k, chn k v nh k.

7.3.5.1 Yu cu vt liu v hnh thc, iu kin p dng kt cu thn k

a) Yu cu vt liu:

Vt liu lm k bo v mi bin cn p ng cc iu kin sau:

+ m bo n nh di tc ng ca sng thit k;

+ m bo bn di tc dng xm nhp mn;

27

+ m bo thot nc qua lp bo v;

+ Thun tin trong thi cng, vn chuyn, lp t, sa cha v thay th;

b) Hnh thc kt cu v iu kin p dng: La chn hnh thc kt cu thn k (Kt cu bo v mi) ph thuc vo ti trng tc ng, cc yu cu v kinh t, k thut, iu kin thi cng, yu cu s dng quyt nh. Bng 16 nu tm tt mt s loi kt cu k ph bin v iu kin p dng. Trn thc t, thit k c th p dng a dng cc hnh loi kt cu bo v khc nhau (khc so vi Bng 16), nhng khi cn phi c nghin cu, kim nghim v tnh an ton, n nh ca kt cu trc khi p dng.

Bng 16. Dng kt cu bo v mi v iu kin s dng

TT Kt cu lp gia c mi iu kin p dng

1 Trng c

- Sng c Hs 0,5m, dng chy c V < 1m/s hoc c rng phng h trc

- Mi ph hp c pht trin

2 hc th ri - Ni c ngun phong ph

- Mi thoi, t yu cu m quan

3 hc lt khan - Ni c ngun phong ph, c loi tuyn chn p ng yu cu thit k

4 hc xy

- Mi m nn cht lng tt

- Sng nh, dng chy mnh, loi ri sn c c kch thc khng p ng c yu cu thit k

5 Thm r

- Kch thc khng p ng yu cu thit k

- Sng ln, c dng chy mnh

- C loi r thp chu mn

6 Cu kin b tng c sn, ghp ri

- Sng ln

- Nn mi cht lng t trung bnh n tt

- Yu cu m quan

7 Cu kin b tng c sn, lin kt mng.

- Sng trung bnh, dng chy mnh

- Yu cu m quan

- Nn mi n nh chng ln tt

- C iu kin thi cng v ch to mng

8 Cu kin cht lng cao (v d nh Basalton, Hydroblock);

- Sng ln

- Nn k (thn ) c cht lng t trung bnh

- Yu cu m quan

9 Hn hp nhiu loi - Mc nc dao ng ln, mi gia c di

- Yu cu s dng khc nhau

28

7.3.5.2 Xc nh kch thc kt cu bo v mi k

- Kch thc c bn ca kt cu thn k l chiu dy ti thiu vt liu lm k (vt liu bo v mi) theo phng vung gc vi mi v trng lng yu cu ca tng cu kin/ khi vt liu. Cn p ng cc iu kin sau:

+ m bo n nh di tc ng ca sng thit k;

+ m bo bn di tc dng ca ngoi lc v xm nhp mn;

+ Thun tin trong thi cng, vn chuyn, lp t, sa cha v thay th;

- Chiu dy ca vt liu bo v mi c xc nh theo cng thc Pilarczyk (1998):

.. . . os

bsp

u m

HDc

(19)

Trong :

- H s n nh biu th cho ngng chuyn ng/n nh ca vt liu. H s n nh cho cc h thng ct liu dng ri di tc dng ca sng, c xc nh

theo cng thc ca Van der Meer (1984):

0,120,186.2 . ( 3)bb

SPN

=

Cng thc ny c th p dng vi 3p (iu kin sng v). Trng hp 3p > vn c th s dng cc kch thc c tnh vi trng hp 3p = ;

Vi: - Gc nghing ca mi dc (mi k) (); Hs - Chiu cao sng thit k ti chn cng trnh (m); trng hp, s dng cc gii php gim sng trc , bi c rng cy chn sng th phi k n h s trit gim sng;

D - Kch thc (chiu dy) c trng ca cu kin bo v;

m - T trng tng i ca vt liu lm cu kin bo v mi, kiu cu trc bo v; D v m c xc nh theo cc h thng c trng nh sau:

* : 503nb

MD D = = (22)

1bmn

= =

Trong : M50: Khi lng trung bnh theo ng cp phi ti m

b: Khi lng ring ca * Khi bo v: D = chiu dy ca cu kin bo v m = ; * Thm bo v: D = d = chiu dy trung bnh ca lp thm bo v;

(1 ). (1 ).( 1) = = b

mn

n n (23)

Vi: n - rng th tch ca vt liu;

- T trng tng i ca vt liu. i vi vt liu hc (khai thc m) thng thng:

(24) (1 ). 1 = =m n b- H s m c lin quan n s tng tc gia sng v loi mi k ( nhm, rng/tnh thm v.v...) (0,5 b 1,0);

+ b = 0,5: vi mi k bng c nhm, thm nc;

+ b = 1: vi mi k bng cc khi xp nhn v t thm nc;

+ b 2/3: gi tr i din thng dng cho cc h thng khc (cu kin trung bnh) v d nh cc khi dng h v cc lp m khi, thm bo v c thit k c bit);

u- H s cht lng n nh mi k, xc nh theo loi kt cu bo v tra ti Bng 17;

30

Bng 17. H s cht lng n nh mi k ( u )

Loi kt cu bo v mi k H s cht lng n nh mi k

( ) u

K 2 lp (gi tr chun) 1,0

K t nhin cht lng km (kch thc khng ng u);

1,0

K t nhin cht lng tt (kch thc ng u); 1,5

Cu kin cht lng cao (Basalton, Hydroblock); 2,0

nha thm nhp; 2,0

Cu kin r ; 2,5

Lin kt mng 2,5

Khi s dng cc cu kin bo v mi dng khc so vi nu ti Bng 17, yu cu thit k phi chng minh c n nh yu cu v tnh tin cy ca cc cu kin thng qua nghin cu th nghim m hnh t l ln hoc th nghim thc t v c c quan qun l cng nhn.

7.3.5.3.C pha bin

C pha bin - thm gim sng nhm gim chiu cao sng leo, tng cng n nh cho thn , thng c b tr vng c sng ln.

Cao trnh c ngang cao trnh mc nc thit k s t hiu qu gim sng ln nht.

Chiu rng c ti thiu bng 3,0m; bng hoc ln hn 1,5 ln chiu cao sng nhng khng vt qu chiu di sng nc su (Bc 0,25L0).

B tr cc m gim sng v dc v pha bin t 1/15 n 1/20 gim chiu cao sng leo, tiu tn nng lng sng. gim sng leo do tc ng ca c c xc nh theo Ph lc C

i vi nhng tuyn bin quan trng, quy m ln, cao trnh v kch thc c gim sng c th xc nh thng qua th nghim m hnh.

7.3.5.4.Chn k pha bin

Vic tnh ton kch thc, la chn kt cu chn k phi cn c vo cc yu t gy xi chn cng trnh gm: sng v (gn chn cng trnh), sng leo v dng rt trn mi , sng phn x, tnh cht c l ca bi trc ; vt liu bo v mi, bi trc la chn kt cu ph hp. Thng thng c 02 loi kt cu chn k: chn k nng; chn k su.

a) Chn k nng

- iu kin p dng: Chn k nng c p dng cho vng bi, ch chng tc ng ca sng v dng chy do sng to ra.

- Hnh thc p dng:

31

+ Thm ph: c b tr ni hoc chm, chiu dy bng (12) ln chiu dy lp bo v mi pha trn i vi thm ph ni v (2 3) ln i vi thm ph chm;

+ M : L hnh thc kt hp gia kt cu thm ph ni v thm ph chm, ph hp vi khu vc c cao trnh bi thp;

+ Thm chn trong t: thng c ng dng cho khu vc c cao trnh bi cao, i vi bi thp nn s dng lng th hoc cu kin b tng c sn. su c xc nh theo iu kin a hnh bi, chiu cao sng, dng chy v.v

+ Thm hoc r xp: C tc dng y h xi ra xa chn k, lm gim nguy c xi l chn k cng nh mi pha bin. Chiu di thm phi bng (34) ln chiu cao sng c ngha trc chn cng trnh i vi kt cu thm ni v (23) ln i vi kt cu thm chm.

Mt s dng chn k nng ph bin c minh ha trong Hnh 5.

Dng b chm c dm kha

Ym.e

Hs

Dng cc c / bn c kt hp lng th gia c b

Bn BTCT

Cc BTCT hoc cc g

hc

MNTKLp bo v

ng trn BTCT

ng buy

Dng ng buy n kt hp lng thgia c bng hc gia c bng hc

MNTKLp bo v

ng trn BTCT

ng buy

Dng ng buy i kt hp lng th

Hnh 6. Mt s dng chn k su

c) su xi ti hn

su xi ti hn ca chn k pha bin ph thuc vo nng lng sng v a cht nn, c tnh ton theo cng thc kinh nghim sau:

Smax = 1,5Hs (25)

Trong :

Smax - Chiu su h xi cn bng (m);

Hs - Chiu cao sng thit k (m);

Ls - Chiu di sng thit k (m);

Cn c chiu su h xi quyt nh phm vi gia c chn k. Nu bo v chn k theo phng ng, su bo v ti thiu bng 1,25 ln chiu su h xi. Nu bo v theo phng ngang, b rng lp bo v ti thiu bng t 3 n 4 ln chiu cao sng thit k ti chn cng trnh. Nu kt hp cc hnh thc trn, ty theo tng trng hp c th quyt nh.

Ngoi vic tnh ton xi ti hn do nh hng ca sng nh cng thc nu trn, i vi khu vc d n cn b xi l do nh hng ca dng ven, mt cn bng bn ct nhng khu bin tin, cn iu tra qu trnh din bin xi bi ca bi v vng ln cn quyt nh la chn chiu su h xi ph hp, m bo n nh chn k lu di.

33

d) Kch thc vt liu

Vt liu bo v chn k thng thng bng hc, trng lng vin phi ln n nh trc tc ng ca cc ngoi lc, c bit i vi dng chy rt xung khi sng leo ln mi.

Trng lng n nh ca vin gia c chn k (G) ph thuc vo vn tc cc i ca dng chy do sng to ra chn k v c tra theo Bng 18.

Bng 18. Khi lng vin bo v chn k theo Vmax

Vmax (m/s) 2,0 3,0 4,0 5,0

G (kG) 40 80 140 200

Trong , Vmax l vn tc cc i ca dng chy do sng to ra chn k c xc nh theo cng thc sng ng ca Izbas:

s

s

s

Lh

gL

HV

..4sinh..

.max

= (26)

Vmax - Vn tc cc i ca dng chy (m/s).

Ls, Hs - Chiu di v chiu cao sng thit k ti chn cng trnh (m).

h - su nc ti v tr nh chn k (m).

g - Gia tc trng lc (m/s2).

Chiu di sng thit k (Ls) c th xc nh theo Bng tra cc tham s sng ca Wiegel (1964);

Lu :

- Trong khu vc nc nng (h/L < 0,05), chiu di sng thit k c th c tnh theo cng thc:

L T gh= (27) - Khi s dng Bng 18 trn c th ni suy hoc ngoi suy cc gi tr khi lng vin (G) t cc gi

tr vn tc Vmax tnh c cn c vo cc s liu cho trong bng.

7.3.5.5. Thit k kt cu nh k

a) i vi c tng nh: Phn tip gip gia thn k v tng nh l nh k (Hnh 7 )

34

Hnh 7. Cc dng kt cu nh k c tng nh

b) i vi khng c tng nh:

nh k l phn tip gip vi g an ton pha bin, thng c thit k cu to ph thuc kt cu mt .

7.3.5.6. Thit k tng lc

a) Tng lc bng ct liu ri

Thit k tng lc ht cn c thc hin theo trnh t v cc yu cu k thut tng t nh trong TCVN 8216:2009 - "Thit k p t m nn" v TCVN 8422:2010 - "Cng trnh thu li - Thit k tng lc ngc cng trnh thu cng". Thnh phn ht cc lp ca tng lc cn bo m cc iu kin sau:

+ Tnh n nh bn ngoi: 515

15 1m/s) th trc m hn t xui theo dng chy (

Loi c: Cc khi b tng hnh hp c cht trc tip trn m , hnh thnh thn cng trnh.

Loi d: Trn nh c t khi b tng dng tng gc.

Hnh 14. Cc dng mt ct ngang m hn mi nghing

8.2.2.2. H thng p (tng) gim sng

a) Cu to:

Cn c vo mc ch khai thc, s dng vng bi cn bo v, so snh hiu qu kinh t k thut cc phng n quyt nh. Khong cch gia b v tng gim sng thng ly trong khong 0,5 n 0,85 ln chiu rng vng sng v trong iu kin thit k. Thn tng gim sng c mt mt ct ngang gn nh ng u trn ton b chiu di v lm vic 2 pha: pha bin v pha b (Hnh 15).

41

1) Mt bng

2) Nhn chnh din t b;

3) Ct ngang

Hnh 15. S cu to tng gim sng

b) B tr tng gim sng

-Tng gim sng: b tr ngm, t cch b mt khong cch nht nh, trc tng song song vi b.

- Tng gim sng c th b tr thnh tng on ngt qung trong phm vi ht chiu di b cn bo v, on ngt qung nhm trao i bn ct gia pha ngoi v pha trong tng. Tng gim sng lm vic c hiu qu khi bin triu nh hn 1,0m.

- Chiu di on tng ly bng (1,52,5) ln khong cch gia tng v ng b, khong cch on tng ngt qung ly bng (0,40,6) chiu di mt on tng v bng hai ln chiu di sng.

- Cao trnh nh tng nh: c th ly bng HTp + 1/2 HS v tr + ln.

- Cao trnh nh tng ngm: c th ly bng HTp - 1/2 HS v tr + ln.

(nh tng ngm thng t thp hn cao trnh mc nc thit k 0,5m).

- Chiu rng nh tng gim sng: Xc nh qua tnh ton n nh cng trnh, thng ly ln hn su nc di Ztp v tr tng.

8.2.2.3. Xc nh kch thc kt cu bo v mi p: Kch thc v trng lng khi ph mi p c xc nh theo hng dn nu ti Ph lc F.

42

8.3. Nui bi nhn to

8.3.1. Khi nim, qu trnh hnh thnh v pht trin

Nui bi nhn to l loi cng trnh dng phng php vn chuyn bn ct t ni khc n b vo khu b, bi bin cn thit bo v duy tr, ci thin s n nh ca b bin hoc to ra mt bi bin theo mun, khi phc trng thi t nhin.

8.3.2. Trnh t thit k

- nh gi qu trnh din bin v hin trng ca bi bin.

- T chc quan trc, nghin cu xc nh bin ng ca bi.

- Xc nh tng lng bn ct thiu ht b sung theo nguyn tc khi lng b sung ln hn khi lng mt i vi thnh phn ht ln hn.

- Xc nh ngun, khi lng v cht lng ct b sung.

- Xc nh v tr nui bi ( ct) dc tuyn b b xi.

- Lp k hoch theo di, gim st sau khi thc hin nui bi.

- Thi gian b sung khi lng nui bi ph thuc vo mc din bin ca bi v iu kin thi cng.

- Kt hp trng cy gi bi.

- Lp k hoch theo di, gim st, duy tu, bo dng, ti nui bi sau khi cng trnh xy dng.

8.3.3. Cc thng s c bn ca cng trnh nui bi nhn to

Cng trnh nui bi nhn to gm cc thng s c bn cn xc nh nh di y (Hnh 16):

+ Hnh dng mt ct ngang: Trc khi nui bi (hin trng) v sau khi nui bi.

+ Phm vi nui bi.

+ Cao v mi dc thit k.

+ Cao , chiu rng, mi dc thm bi.

+ Thnh phn ht ca bi t nhin v ca vt liu b sung.

+ Khi lng nui bi ln u v khi lng tng cng theo nh k.

+ Chu k nui bi.

43

Bm

Cao n ct

Cao thm c

ng a hnh t nhinMt ct thit kMt ct thit k + nui bi tng cng

Mc nc

-6

-4

-2

0

2

4

0

100 200 300 500 6004000

Dc

W

Hnh 16. Cc thng s c bn ca mt cng trnh nui bi nhn to

8.3.4 Hnh thc nui bi

Cc d n nui bi nhn to c th phn thnh 3 loi chnh sau:

- Chuyn ct trc tip ti ni cn nui bi;

- D tr ct nui bi;

- Nui bi lin tc.

Hai hnh thc nui bi u tin thng c s dng trong cc d n nui bi. Hnh thc nui bi lin tc l dng c th hay c s dng trong h thng chuyn ct ti ca sng hoc ca vo ca mt cng bin trnh hin tng bi lp lung tu vo cng v hn ch s gin on dng vn chuyn bn ct dc b.

8.3.5 V tr nui bi

Ct nui bi c vo cc v tr c thit k ph thuc vo mc tiu v ngun ct c c. V nguyn tc, ct c nh sau

(1) trn bi kh;

(2) trn bi ngp nc;

Nu nui bi nhm hn ch hin tng xi l b thng xuyn, th ni p dng tt nht l ln bi kh v ct t khong gia mc nc thp n chn ca n ct hoc mc nc triu cao.

Nu khu vc d n nui bi khng c ngun ct, phi s dng ngun ct ngoi khi th phi dng bin php ct vo bi trc, trong phm vi ca vng sng . Tuy nhin, ct c th ti phn b hp l trn mt bi ti gii hn ng sng v th nn chn thi im ct c thi tit tt, gi nh, sng khng ln v ngay gn mp nc chng trn dn ln bi.

44

8.3.6 Khi lng ct s dng nui bi

Khi lng bn ct cn c cung cp nui bi c lin quan mt thit ti tc vn chuyn bn ct dc b. Tc vn chuyn bn ct dc b, thi gian nui bi v th tch ct cn thit hnh thnh nn mt hnh dng mt ct ngang bi bin n nh theo yu cu l cn c xc nh tng th tch ct cung cp cho mt bi bin c th.

8.3.7 Yu cu v kch thc ca vt liu s dng nui bi

Bn ct khi s dng nui bi phi c ng knh trung bnh bng hoc ln hn kch thc ca ht ct ti ni nui bi. Tuy nhin, s khc bit gia hai kch thc ht ct trc v sau khi nui bi khng nn qu ln, v n c th to thnh cc mi dc vt qu mc cho php hoc gy hin tng xi l h lu ca bi ct c nui dng do cc ht ct th b gim s di ng.

Mt im na cn quan tm l hm lng st v ht mn c trong ct s dng nui bi. m bo cc yu cu v qu trnh sinh hc, cht lng mi trng nc v cn bng sinh thi vng b th ct s dng nui bi phi c t ht mn. Nu ct s dng nui bi cha qu nhiu ht mn hoc st th phi ra sch trc khi s dng nui bi.

8.3.8 Ngun ct nui bi

Ngun ct s dng nui bi c th ly t vng nc su ngoi khi, hoc c th kt hp ly t d n khc trong cng khu vc, v d kt hp d n no vt m rng hay khi su lung tu phc v giao thng vn ti thy. Ngoi ra c th s dng ngun cung cp bn ct cc bi bin ang c bi tch ln cn.

9. Qun l v bo v cn ct ven bin

9.1.Vai tr ca cn ct ven bin

Cn ct c hnh thnh qua nhiu nm do gi thi mang ct n b gi li bi thm thc vt hoc cc vt cn khc trn vng bi bin

Cn ct min Trung Vit Nam gi vai tr nh cc tuyn bin t nhin bo v cc vng t pha trong t lin khi b thit hi do cc tc ng ca triu cng, gi, bo, sng v ngp lt.

Ty theo v tr a l, phm vi, kch thc, hnh dng, quy m ca cn ct v mi quan h ca chng i vi cc yu t hi vn v a hnh vng t pha trong t lin, vai tr bo v ca cn ct c phn thnh cc mc sau:

- Cn ct c vai tr bo v thp: trong trng hp ny cc khu vc h tng, dn c nm pha sau c cao mt t t nhin trung bnh ln hn cao nh cn ct v c ngn cch vi cn ct bng cc m, ph , lch sng - Hnh 17 (a)

- Cn ct c vai tr bo v trung bnh: vi trng hp ny, cc khu vc h tng, dn c nm pha sau cn ct c cao mt t t nhin trung bnh ln hn cao mc nc bin cao nht trung bnh v thp hn mc nc bin trong bo Hnh 17 (b)

45

- Cn ct c vai tr bo v cao: vi trng hp ny, cc khu vc h tng, dn c nm pha sau cn ct c cao mt t t nhin trung bnh bng hoc thp hn mc nc bin cao nht trung bnh v thp hn nhiu so vi mc nc bin trong bo Hnh 17 (c)

Hnh 17. M t vai tr bo v ca cn ct ven bin

9.2. Phm vi v cc yu t c trng ca cn ct ven bin

9.2.1 Phm vi cn ct

Phm vi cn ct ven bin c xc nh da theo c trng a hnh v cc yu t mc nc bin, c th l khu vc nm tip gip vi mc nc trung bnh cao nht, vng t lin pha trong v cc gii hn bn c nh du bng s thay i v dc t 1% n di 10% (Hnh 18)

Hnh 18. S ha v m t cc yu t ca cn ct ven bin

46

9.2.2 Tnh ton xi l cn ct

nh gi v d on mc xi l trong bo ca cn ct ven bin thng s dng cc phng php kho st quan trc theo di v cc m hnh tnh hin kh thng dng trn th gii, trong tiu chun ny gii thiu mt phng php v m hnh tnh ton ca H lan, m hnh DUROS-Plus ti Ph lc G.

Hnh 19. S m t xi l cn ct do sng trong bo trn mt ct ngang

9.3. Gii php qun l bo v cn ct ven bin

9.3.1. Gii php khng cng trnh

Nhm kim sot cc hot ng bo v i vi cn ct ng vai tr bin, cn tin hnh cc gii php sau:

- Xy dng, b sung cc vn bn php l qun l v bo v cn ct ven bin vi mc ch phng chng thin tai.

- Tuyn truyn v thng tin nng cao nhn thc cng ng

- Qun l thng nht cc hot ng pht trin kinh t x hi trn phm vi cn ct:

- T chc, thc hin vic o c, theo di cc bin ng ca cn ct

9.3.2. Gii php cng trnh

Trong tiu chun ny, trc mt ch gii thiu mt s gii php bo v tng cng n nh v chng xi l cn ct ph hp vi thc t cn ct ven bin min Trung Vit Nam, bao gm:

- Trng c, to thm ph trn cn ct

- Hng ro chn ct

- Phc hi v ti to li mt ct bi bin v cn ct

- Bo v cn ct bng ti ct

- To cc va ngm trc cn ct

47

- chn sng gn b

10. Yu cu k thut trong thi cng

10.1 Thi cng

10.1.1. Yu cu k thut thi cng

- Thi cng theo tiu chun ngnh TCVN 8216:2009 - "Quy trnh thi cng p t m nn".

- Cn c mt bng v thi gian thi cng ph hp, hn ch nh hng ca thy triu, sng v cc tc ng khc t bin.

- p theo tng lp, chiu dy mi lp khng c ln hn 50cm.

- T chc thi cng theo hnh thc cun chiu, hon thnh tng phn on bao gm c hng mc bo v mi .

10.1.2. Vt liu t p

- t p phi m bo ch tiu c l, tr lng theo quy nh ca thit k, c xc nh c th trong giai on thit k bn v thi cng;

- Nu ly t ti ch ngoi cc yu cu trn cn m bo khong cch t chn ti ni ly t theo quy nh ca Lut iu v khng lm nh hng n rng cy chn sng.

- Thit b m phi ph hp vi ch tiu c l ca t p do thit k quy nh m bo lin kt gia cc lp m thnh mt khi ng nht.

10.2. Thi cng cng trnh bo v mi

10.2.1.K

- m bo cc yu cu k thut, cht lng theo tiu chun hin hnh.

- Cn kim tra cng nn ca phng th nghim p ng yu cu thit k.

- Chiu dy k phi m bo khng sai lch vi thit k qu 5%.

10.2.2 Cng trnh k b tng

Yu cu vt liu ct, si, nc, xi mng dng ch to b tng theo tiu chun Vit Nam hin hnh; Yu cu k thut v Phng php th hn hp b tng thy cng theo TCVN 8218:2009, TCVN 8228:2009 v TCVN 8219:2009.

Tuyt i khng c x dng ct mn, nc mn v cc vt liu khc b nh hng bi nc mn a vo thi cng xy dng cng trnh.

10.3. Thi cng lp lc

i vi lp lc bng vi a k thut: Cht lng vi phi t yu cu thit v kim tra theo TCVN 8222:2009 v TCVN 8482:2010 - "Vi a k thut - Yu cu k thut v phng php th".

48

10.4. Thi cng m hn

- Cn c thit k, nng lc thi cng v mc nh hng ca triu, sng, dng chy i vi cc v tr trn thn xc nh trnh t thi cng phn on, phn lp.

- Phng php xp khi tetrapod trn mi nghing (Hnh 20 )

Hnh 20. Phng php lp t khi tetrapod trn mi nghing

a. Mt ct ngang; b. Mt bng

- i vi khi Tetrapod: s lng lp t thc t so vi thit k khng sai lch qu 5%.

10.5 Mi trng

Trong qu trnh thi cng phi hn ch nh hng n mi trng, trong cn tr trng khng lm tn hi n rng cy chn sng, cn ct t nhin; c gii php hn ch gy n, bi bn khi vn chuyn vt liu v thi cng; hon tr mt bng, ng giao thng do qu trnh thi cng lm nh hng.

11. Qun l, duy tu, bo dng bin

11.1 Qun l

11.1.1 Quy nh chung

- Tun th quy nh ca cc vn bn php lut hin hnh lin quan;

- Kim tra, nh gi cht lng theo nh k;

- xut bin php.

11.1.2. Hng mc qun l

11.1.2.1 ng hnh lang kt hp qun l v bo v

49

ng hnh lang kt hp qun l v bo v phi m bo rng b tr phng tin v thit b hot ng h khi cn thit. Trng hp kt hp lm ng gom dn sinh, ng du lch, khi thit k cn tun theo quy hoch, lu khng phc v nng cp .

11.1.2.2 Nh qun l

Nh qun l h thng bin c thit k ring theo cc tiu chun, quy chun ca ngnh xy dng, thng c b tr gn , khu vc bi n nh, xa khu dn c m bo thun li cho cng tc qun l, cu h, cu nn, khong cch gia cc nh qun l t 3,0km n 5,0km.

Nh qun l thng xuyn chu tc ng t bin, trong c bit l s nh hng ca gi bo v xm thc; vic chn vt liu, kt cu, hng nh,.. phi m bo n nh lu di, an ton trong gi bo. Bn cnh nh qun l thng b tr bi tp kt vt liu phc v cho cng tc h , duy tu, bo dng thng xuyn.

11.1.2.3 Trm quan trc hi vn

Ngoi cc trm hai vn Quc gia, nhng tuyn quan trng hoc nhng khu vc bi bin v b bin b xi, cn xy dng cc trm hi vn o c cc thng s c bn nh triu, nc dng, sng, vn chuyn bn ct phc v cho qun l, nghin cu v thit k.V tr xy dng trm quan trc phi m bo n nh lu di, thun li trong qu trnh qun l v vn hnh.

11.2. Cng trnh ph tr

Ngoi cc hng mc cng trnh chnh, khi thit k cn xem xt tng trng hp c th v yu cu thc t ca khu vc xy dng b tr cc hng mc cng trnh ph tr sau:

- ng vn chuyn thuyn qua (nu c yu cu)

- Bc,dc ln, xung , kt ni vi ng dn sinh, ng cu h ;

- Ca khu qua ;

- Bi vt liu d phng cu h ;

- Bin ghi cc s kin c bit ca tuyn :

Khi thit k nhng cng trnh trn, ti cc v tr ni tip, chuyn tip phi m bo n nh iu v thun li cho dn sinh trong khu vc.

Cng tc du tu, bo dng bin cn tin hnh nh k, nhm tng cng n nh, bn vng cho cng trnh. Trong , cn tp trung vo mt s cng vic chnh sau:

11.3. Kim tra, nh gi trng thi lm vic ca cng trnh

11.3.1 Kim tra nh k

Cng tc kim tra gim st nh k cn thc hin hng nm trc ma bo, vi cc ni dung sau:

- Chiu cao nh , ln ca thn .

- Cht lng bo v mi, thn (n nh mi, hang hc ng vt).

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- Kch thc hnh hc mi k (mt ct dc ngang, chiu dy).

- Cht lng ca cc cng trnh chuyn tip (chn k, tng lc )

- S pht trin ca h xi trc chn (nu c).

- Pht hin cc bt thng dc tuyn

11.3.2. Kim tra theo tnh hung

Theo tnh hung cn bo, trc khi bo n (d bo), nn kim tra tnh hnh k chun b i ph cc tnh hung c th xy ra. Sau cn bo, cn kim tra tnh hnh h hng ca , k c k hoch sa cha, khc phc kp thi.

11.4. Duy tu, bo dng

- Cc h hng trn mi k, khi c chuyn v ln cn phi xp t li c dy cn thit. Vt liu c th ti s dng nhiu ln nh: cn thay th nhng vin b v, b mi mn nu trn mi xut hin nhng ch trng vi din tch ln, gy ra s ra tri ca vt liu thn , cn phi sa cha kp thi.

- Chn k, m hn cn theo di v bo dng thng xuyn, c bit trong trng hp c h xi pht trin mnh trc chn cng trnh, phi tin hnh x l khi h xi cn quy m nh. Nu h xi hoc h hng pht trin rng va phi x l tn km va e da an ton cng trnh.

- Thng xuyn duy tu, chm sc rng ngp mn, m bo trng thi, cht lng rng theo iu kin thit k.

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Danh sch T son tho

(Theo Quyt nh s 3469/Q-BNN-KHCN ngy 04/11/2008 v Quyt nh s 1522/Q-BNN-KHCN ngy

07/6/2010 ca B trng B Nng nghip v Pht trin nng thn)

TT H v tnChc danh

trong t son tho

n v cng tc

1. Th.S Trn Quang Hoi T trng, ch bin Cc Qun l iu v PCLB - Tng cc Thy li

2. PGS.TS. V Thanh Te T trng Trng i hc thu li

3. PGS.TS inh V Thanh Ph t trng V Khoa hc, Cng ngh v Mi trng - B Nng nghip v PTNT

4. PGS.TS. Nguyn Bnh Thn Ph t trng V Khoa hc cng ngh v HTQT - Tng cc Thy li

5. PGS.TS. V Minh Ct Thnh vin Trng i hc thu li

6. Th.S L Thanh Chng Thnh vin Vin Khoa hc thy li min Nam - Vin KHTL VN

7. PGS.TS. Nguyn Quc Dng Thnh vin Vin Thy cng - Vin KHTL VN

8. PGS.TS L Mnh Hng Thnh vin Vin khoa hc thy li Vit Nam

9. PGS.TS. Trnh Vn Hnh Thnh vin Vin Phng tr mi v bo v cng trnh - Vin KHTL VN

10. TS. inh Vn Mnh Thnh vin TT kho st, nghin cu mi trng bin - Vin C hc

11. Th.S Nguyn S Nui Thnh vin Nguyn Ph cc trng Qun l iu v Phng chng lt bo

12. PGS.TS. Nguyn Khc Ngha Thnh vin Phng th nghim trng im quc gia v ng lc hc sng bin - Vin KHTL VN

13. TS. Nguyn Hu Phc Thnh vin Cc Qun l iu v Phng chng lt bo

14. GS.TS Phm Ngc Qu Thnh vin Trng i hc thy li

15. PGS.TS. Nguyn B Qu Thnh vin Trng i hc thu li

16. PGS.TS. Nguyn Ngc Qunh Thnh vin Phng th nghim trng im quc gia v ng lc hc sng bin - Vin KHTL VN

17. Th.S Nguyn Tun Anh Thnh vin th k V khoa hc, Cng ngh v Mi trng - B Nng nghip v PTNT

18. TS. Mai Vn Cng Thnh vin th k khoa hc Trng i hc thy li

19. PGS.TS L Xun Roanh Thnh vin th k Trng i hc thy li

20. Th.S Nguyn Vn Hi Thnh vin th k Cc Qun l iu v PCLB - Tng cc Thy li

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a) trc din vi bin, khng cho php sng trnb) trc din vi bin, cho php sng trnYu cu k thut i vi c pha bin - thm gim sng, xem quy nh ti mc 7.3.5.3. Chn pha bin cng l chn k bo v mi pha bin c th hin mc 7.3.5.4.f) Cng trnh ct qua thn a) n nh chng trt phng