K - H~ s6 xet d6n rnue d<)tang cua song dQe thea chi~u dili truy~n song.
-Q4E.
E: dQ d6c cua song (E = h /1..).
Ba gio D ph\! thuQc vao hinh d"mg va chieu dai vung mi;itnuac t<.10song . (mi;it h6 chua, mi;it song ...) xac dinh theo th\lc t~, nhung khong dugc 100
hem tri s6 da gio tai h<.lll(DK) tinh theo cong thuc sau:
DK =30EV2
2
2
a - H6 fQng b - H6 dili c - H6 congHinh 3.3. Sa d6 cae d(U1gh6 chua Hinh 3.3. Sa d6 cae d(U1gh6 chua 1. Bo chtln song (B?p, de ... ) 2. H6 (3-14) (3-13) 1 9 + 1geY E=---l-' 0.2 o 0.2 0.4 0.6 0.8 1.0 H/ilo
Hinh 3.4. Quan h~H/,-o vtJi a, Il
(3-15)~I--- ~I--- ./ Il I?' OJ 1/ 1/ i'a 0.8 0.6 0.4
Trang h6 chua co th€ xac dinh D nhu sau: G9i chieu dai va chieu rQng trung binh cua vUng mi;itnuac t<.10song la Do va B'b' Khi vling mi;itnuac t<.10song rQng Do<5B'b (Hinh 3.3a) I&y D=Do' Khi vling mi;itnuac t<.10song hyp va dai Do:;' 5B'b (Hinh 3.3b) I&y D=5B'b' Khi vling mi;itnuac
a;1l
t<.10song cong (Hinh 3.3c) I&y D b~ng khoang cach th~g goc ti! biYch~n song tinh 1.0 toan d~n biYd6i di,;\n. .
a, ~ - Cac h,;\ s6 xet d~n dQ nong cua
nuac, ph\! thuQc vao tY s6 HlI..Q, tra theo
bi€u d6 hinh (3.4).
ho,1..0: chieu cao va chieu dai song khi gia thi~t dQ siiunuac trang h6 H la vo h"m.
b. Xac a;nh at? cao tir mvc nuac tfnh ainauimg trung tam song -ho (m) auimg trung tam song -ho (m)
h = nh' .cth 2nH
o I.. I..
H - Chieu siiu trung binh cua nuac tmac biYch~n song (m).Khi vung t<.10song nho co th€ bo qua ho. Khi vung t<.10song nho co th€ bo qua ho.
c. Xac a;nh chi~u cao song leo tren biT chiin song nghieng
BQ leo cao cua song len biYch~n nghieng, co d(\ xoiii m g6m chieu cao nuac
denh do gio i\h va chieu cao song leo hsl (Hinh 3.5). Tri s6i\h va hsl co th€ tinh theo cac cong thuc sau:
J<I(3-16) (3-16) M\lC nuoc dSnh do gio M\lc nuoc tInh (3-17) Dv' M1 =6.10-3.-' -coso. 3g.H h =2-AKh ,I m
a - Goc nghieng giua huanggio v61 mij.t ph~ng th~ng dfrng gio v61 mij.t ph~ng th~ng dfrng vuong goc vai mai ba chdn, d(\.
A - H~ 56 ph\! thu(\c VilO tY 56 Hinh 3.5. Sadb song leo tren b" ch~n
giua A.: Khi A. s10: A = 3,2 Khi A. > 10: A =3,8
h h h
K - H~ s6 ph\! thu(\c VilO d(\ nMm cua mai bachdn:
Mai him bkg be tong: K = 1,0; lam b~ng da x~p, da d6: K =0,77
3. Tinh toan ap b!csong (Truang h(lpbachcinsong thcingd(mg)
G. Ovitngnu&csiiu (H>1,5h)
Trung tam song M\lc nuoc tI Po ~ yH+p, Kh. A a- IH <- 2 j YA/2 b-KhiH>~ 2 B
Hinh 3.6. BiSu db ap l\lc song tac dVng lenMch~n th~ng dUng 0 vimg nuoc sau
6vimg nuac sau, khi dinh song (y sat v61ba chdn song, bi~u db ap h;c song lenbiY chk thimg dfrng co dr;mg nhu hinh (3.6a) khi H < ~ va nhu hinh (3.6b) khi biY chk thimg dfrng co dr;mg nhu hinh (3.6a) khi H < ~ va nhu hinh (3.6b) khi
H> ~ . Tri 56 cuang d(\ ap h;c song (y day ba chdn Pc (y hinh (3.6a) tinh thea cong thuc sau:
h
p, =y. 21tHch-- ch--
Ie
(3-18)
y - IrQng lugng rieng cua nuac
Ngoai ra.khi dinh song sat biJ"chfuJ song va H < ~ ' tri s6 t6ng ap h,rc th<1mdiiy n6i duai day cong trinh se tang them mQt gia tri nhu sau:
w = P,.B
sdd 2 (3-19)
B: chi~u rQng (theo phuang truy~n song) day biJ"ch~n (m)
D~ xac dinh tri s6 va di~m d(it cua ap h,rc ta nen dung phuang phap phiin bi~u d6: Phful bi~u d6 thanh cac bi~u d6 dan gian (chii nh(lt, tam giac) d~ tinh.
b. 6vitng nu:o-c sau nhung bi cqn a{;l ng{;l
dvimg nuac co H >Hpg nhung tmac biJ"ch~n, day biJ"cao len tuang d6i dQt ngQtva co H <Hpg (Vi d\l cua van ph~ng cua d(lp tran) thi bi~u d6 ap l\l'c song co d:;mg va co H <Hpg (Vi d\l cua van ph~ng cua d(lp tran) thi bi~u d6 ap l\l'c song co d:;mg nhu hinh (3.7a). Iri s6 cQtnuac phan gi6'i Hpg sabQI<1y: Hpg =(1,5 -7 2)h
,~ ~L 11: ~ ~L 11: ~ ::r: :r: v 1\ :r: " :r: / p, a - b-
Hinh 3.7. Sa db lip IlfCsong len mill! ch~n song th~ng dUng
a - Khi avimg nuac sau nhung co dja hinh cao dQt ngQt b -0vimg song db
DQ vuQt cao cua song Z tren m\l'cnuac tinh tinh nhu sau:
Z =(0,8 ~ - 0,2 }h (3-20)
Irj s6 wang dQ ap l\I'c cua bi~u d6 &ngang m\l'cnuac tinh Po va t'ili day biJ"ch~n song Pc xac dinh nhu sau:
P =Ah 1,5o H o H --01 h ' (3-21) (3-22) H p, = 0,6P'h c. (; vimg song ab (H <HpgJ
Bi~u db ap l\Ic song co d(lng nhu hinh (3. 7b).
Tri s6 cuang dQ ap l\Ic cua bi~u db co gia tri lem nh~t t(li dQ sau hl3 so vai m\IC
nuac tInh vii duQ'c tinh theo cong thuc sau:
= 17(0,75C+ vJ'
PO' 2g
Vs - V~ t6c cua song t(li vi tri Z =0 (m) xac dinh theo cong thuc sau:
V = 7th cth 27tH
'2 A