- TUUng ngll'c
3. Cae b9 pMn acua VtlO, cua ra
cdumang .
. Cach chQri cac bQ ph~ 6 cua vao, ctiara du mang tuong t¥ nhu c6ng
, 1 d
luon. De am bao dong chay vao, ra mang dUQc em thu~ va giam t6n thAt CQtnuac qua mang, tuimg cAnh Clla cAu mang ciing thuimg chQn d(lIlg xo~ vo
. _ Khi chQn dang m~t c~t cira vao nen chy y hi~n tugng nucrc dang, nucrc d6 tru&c b~c, d6c nucrc (xem phAn tinh toan khAu di~n)
- PhAn cira ra: chQn cAu tl;lOnhu c6ng h6'.
2. Than Me n1IUe ,
B~ nu&c 6' cong trinh tren kenh thuemg sir d\lllg dflllg b~c nucrc m(\t cap nhu hinh ( 3-32)
•• ..
. ... /r .
.•.•.•...•.-•..•.•...•..••..•.•...•....•.•.
I.CSu c()ng llic; 2. Khe phai dieu til!!;
Hinh 3-32. CAu ~o b~ nu<1Cm(l!clip
J-
- D(\ d6c day b~c thuemg chQn i=35.;- 50%
- PhAn day cua b~c co the lam dflllg lOp pM ho~c lam dflllg tuemg trQng h,rc bkg be tong, da xay. DfIllg tuemg trQng h,rc t6n kh6i lugng vii kho xay d1,Illg,thuemg chi dUng khi nenyeu.
- Tuemg ben cua b~c chQn nhu tuemg ch~ ddt.
3. Than dt5e nuue
- D6c nucrc chi khac b~c nucrc Iii d(\ d6c cua d6c xolii hon cua b~c nucrc, nen cm€u dili than d6c dili hon.
- D(\ d6c day d6c thuemg chQn i <10%.;- 20% vii nen chQn i xdp xi d(\ d6c dja hinh
de giam kh6i,lugng dilo d~J?' ., ", , ,
- Chieu r(\ng cua doc co the lam bang ho~c thu hlllPdan ve phia cuoi doc de giam kh6i lugng xay d1,Illg(neu d6c r(\ng).
- Day d6c Iii m(\t lOp pM bkg be tong c6t thep, be tong, da xay. DfIllg be tong c6t the!? chi sir d\lllg khi luulugng ,cua. d6c l&n, ho~c n€n yeu; DQc d6c nucrc co the b6 tri nhieu lo~i v~t li~u, lo~i v~t li~u tot bo tri 6' phiin doc co v~ toc dong chay l&n.
- Tuemg ben eua d6c nucrc ding chQn nhu tuemg ch~ ddt.
3.5.6.LljlI chQn cdnt\lo tran ra, tran bang
1. Trim biing
a.Cdu tgo phtin eua vao, ra tran ra
Hinh (3-33) mo tli m(\t dflllg triln bang thuemg g~p.
- Cira vilo triln bang thuemg, liIJ;1trUnf v6i mai ngoili Clla kenh. De t~p trung nucrc mua trucrc khi chay vilo triln co the bO tri ho t~p trung nucrc 6' chan mai ngoili kenh, V~t li~u thuemg dUng Iii be tong, be tong c6t thep, da xay ...
- Bcr kenh phia cira vilo, neu khong du d(\ cao cAn lam them bcr bao de nucrc khong triln vilo kenh.