N CP THOT NC BN TRONG CNG TRNH
N CTN BN TRONG CNG TRNH GVHD: PGS.TS NGUYN VN TN
GII THIU CNG TRNH1. c im cng trnh- Cng trnh cn thit k h thng cp
thot nc y l mt bnh vin. Mt s thng s thit k c bn c cho nh bng
sau:
Bng 1.Cc c im ca cng trnh cn thit kc im thit k cng trnh
S tng nh6 (tng)
Chiu cao mi tng3.5 (m)
Chiu cao hm mi2 (m)
Chiu dy mi nh0,4 (m)
Chiu cao tng hm2.5 (m)
Ct nn nh tng 1+8.8 (m)
Ct sn nh+7.2 (m)
su chn cng cp nc bn ngoi0.5 (m)
p lc ng ng cp nc bn ngoi
6(m)
5 (m)
KHI LNG THIT K2. Khi lng thit k- Bao gm cc cng tc sau y:
1. Mt bng cp thot nc khu vc nh.
2. Mt bng cp thot nc cc tng nh.
3. S khng gian h thng cp nc lnh, cp nc nng, thot nc bn.
4. Mt bng v s h thng thot nc ma trn mi.
5. Mt ct dc ng ng thot nc ngoi nh.
6. Thit k k thut mt vi cng trnh trong h thng.
7. Thuyt minh tnh ton v khi ton kinh t.
PHN 1. CP NC LNHI.LA CHN S H THNG CP NC LNH T cc s liu trn theo
s b ta thy p lc ng ng cp nc bn ngoi khng cp cho nh, v vy ta phn 6
tng nh thnh 1 vng, s dng h thng b cha, trm bm v kt nc cung cp nc
cho ton b ta nh.II. VCH TUYN V B TR NG NG CP NC BN TRONG NH Mng li
cp nc bn trong bao gm: ng ng chnh, ng ng ng v cc ng nhnh dn nc ti
cc thit b v sinh.-Cc yu cu phi m bo khi vch tuyn:
+ ng ng phi i ti mi thit b v sinh trong nh.
+ Tng chiu di ng ng l ngn nht.
+ ng ng d thi cng v qun l sa cha bo dng.
Trn c s ta tin hnh vch tuyn nh sau:
+ B cha v bm c t trong tng hm.
+ Kt nc c t trn tng mi.
+ ng ng chnh c t sn hm mi.III.XC NH LU LNG TNH TON3.1. Xc nh lu
lng nc tnh ton cho tng on ng v cho ton ngi nh- Lu lng nc tnh ton c
xc nh theo cng thc sau:
qtt = 0,2((( (l/s)
Trong :
+ qtt: Lu lng nc tnh ton.
+ (: H s ph thuc vo chc nng ca ngi nh, i vi bnh vin a khoa th
theo TCVN 4573-88 (Bng 14.8-CTN) ly, ( = 1.4.
+ N: Tng s ng lng ca cc thit b v sinh trong on ng tnh ton. Ly
theo bng 18.1- CTNBng 2. Thng k cc thit b v sinh trong nhSTTTn thit
bS lng
(ci)Tr s ng lng mt thit b (N)Tng s ng lng tnh ton
1Vi nc thng ra h x360,518
2u tiu600.1710,2
3Vi nc chu ra mt420,33 13,86
Tng cng42,06
(N = 42,06Vy lu lng nc tnh ton ca ton bnh vin l:qtt = 0.2(1.4(
=1,816 (l/s)Theo PL1 th tiu chun dng nc tnh cho mi dng bnh l 200
l/ging. ngChn ng h:
- Theo tnh ton trn lu lng cho ton khu nh l:
qtt = 1,816 (l/s)
Theo bng 17.1 (trang206 -CTN) th ta chn ng h loi tuc bin BB c
50mm vi lu lng c trng l Qtr =6,54 (m3/h), v c sc khng l:
s=2.65(10-2. v:qmin = 0.9 (l/s) , qmax = 6 (l/s)
hh = s(q2 = 0.0265(1.8162 = 0.087m < 1( 1.5 m
- Vy chn loi dng h tuc bin BB 50 l hon ton hp l.3.2. Tnh ton thy
lc - Da trn c s vn tc kinh t v = 0.5 ( 1.5 (m/s), xc nh ng knh thch
hp ca tng on ng, tn tht p lc ca tng on ng v ton mng. T xc nh Hyc,
xc nh th tch b cha v kt nc.
- Tn tht p lc theo chiu di cho tng on ng c xc nh theo cng
thc:
h = i(l (m)
Trong :
+ i: Tn tht n v (mm).
+ l: Chiu di on ng tnh ton.
- Khi tnh ton ta tnh cho tuyn bt li nht v cng chnh l tn tht p lc
ca ton cng trnh. Cc nhnh khc khng cn tnh ton m chn theo kinh nghim
da vo tng s ng lng ca on tnh ton.Bng 3. Tnh ton thy lc t im bt li
ti kt nc
on ngS thit b v sinhNq (l/s)D (mm)V (m/s)1000iL (m)h = iL
Chu raTr s lu tiuTr s lX btTr s l
A1-A220.3360.1720.52.680.46202.28471.093.51.65
A2-A320.3360.1720.55.360.65251.98272.933.50.96
A3-A420.3360.1720.58.040.79251.48120.003.50.42
A4-A520.3360.1720.510.720.92321.7152.863.50.54
A5-A620.3360.1720.513.41.02321.85178.203.50.62
A6-A720.3360.1720.516.081.12401.3577.2320.61.59
A7-A8120.330020.041.25500.9632.111.350.04
A8-K120.33240.17240.540.441.78501.3659.865.50.33
Tng456.15
Iv. Xc nh dung tch v chiu cao t kt nc
4.1. Xc nh dung tch t kt nc - Kt nc c chc nng iu ho nc, tc l d
tr nc khi tha v cung cp nc khi thiu, ng thi to p lc a nc ti cc ni
tiu dng. Ngoi ra kt nc cn phi d tr mt lng nc dng cho cha chy trong
ngi nh.
- Ta s dng 1 kt nc cho ton to nh:
- Dung tch ton phn ca kt nc c xc nh theo cng thc sau:
- Dung tch ton phn ca kt nc c xc nh theo cng thc sau:
Wk =K ( (Wh + Wcc(10)) (m3)
Trong :
+ Wh: L dung tch iu ho kt nc (m3).
+ K: H s d tr k n chiu cao xy dng v phn cn lng y kt nc, gi tr ca
K ly trong khong (1.2 ( 1.3), chn K= 1.3.
- Theo tiu chun lng nc cho mt vi phun cha chy v s vi phun hot ng
ng thi ta thy v y l bnh vin c khi tch khong 11858 m3 > 25000 m3
nn c 2 vi phun hot ng ng thi, lu lng ca mi vi l 3 l/s. Vi lu lng
cha chy trong 10 pht l:
Wcc(10)= 2 ( 2,5(10( 60 = 3000 (l) = 3 (m3)
- Do cng trnh c lp t trm bm v kt nc (trm bm t ng)
Wh = (m3)
Trong :
+ Qb: L cng sut my bm
Qb = qtt 3,6 = 1,816 3,6 = 6,54 (m3).
+ n: S ln m my bm trong 1 gi, chn n = 2( Wh = = = 1,64 (m3)
- Th tch xy dng ca kt nc:
Wk = 1,3( (1,64 + 3) = 6 (m3)
- Xy dng kt nc c kch thc: 2(2(1,5 (m).
4.2. Xc nh cao t kt ncCao t nc c tnh theo cng thc:
Hk = hA6td+hA6-K+HA6+hcb
Trong : h6td: p lc t do ti im A6, ly hA6td= 3 (m)
h6-K: Tng tn tht t im 6 n y kt nc. Theo bng tnh ton thu lc (bng
III) ta c hA6-K= 1,96 (m) HA6 : Cao ca im A6 trn s cp nc HA = 8,8 +
5 x 3,5+0,6 = 26,9 m. hcb = 25% = 0,256,15 = 1,5 m .Do :
Hk = 3 + 1,96 + 26,9 + 1,5 = 33,36 (m)
Kt nc nc cao hn mi nh 33,36 (8,8+3,56+2,5) = 1m
V vy t kt nc ln hm mi l ph hpV. Tnh ton p lc cn thit cho ngi nh
p lc cn thit ca bm l p lc c th a nc t b cha ln kt nc trn lng cu
thang xc nh theo cng thc sau :
Trong :
+) hhh - chnh cao hnh hc gia mc nc cao nht trong kt nc v mc nc
thp nht trong b cha Cao ca b cha bng ct nn tng hm hbc = 6,3m =>
ct ca mc nc thp nht trong b l 6,6 (Gi s mc nc thp nht trong b l 0,3
m).Cao cua kt nc la 33,36 ( chiu cao cng tac cua b la 2 m, gia s lp
cn ay b la 0,3m)=> ct mc nc cao nht trong ket nc la
35,3+0,3+2=35,66m =>hhh = 35,66 6,6 = 29,1(m).
+) hdh: tn tht p lc qua ng h: hdh = 0,087 (m).
+): tng tn tht p lc trn ng t bm n kt, ta c qtt = 1,82 (l/s) chn
ng cp nc t bm ln kt D63, tnh ton thy lc ta c: v = 0,878 (m/s),
1000i = 20,62 ( m).Chiu di on ng l: 33,36 -6,3 = 27,06 m
( vi 35,3m la cao t ket, 6,3 l ct nn tng hm )
= (27,06 x 20,62)/1000= 0,56 (m). +) hcb: tn tht cc b, ly bng
20%
hcb = 20% x 0,56 = 0,11 (m).
+) htd: p lc t do ra khi ming vi, ly htd = 2 (m).
Ta chn 2 my bm: 1 cng tc, 1 d tr c lu lng v ct p nh sau:
= 32 (m), QBom = 2 (l/s).vi. Tnh ton h thng cp nc cha chy - H
thng cp nc cha chy tch ring khi h thng cp nc lnh. Cc vi cha chy c t
trong cc hp cha chy v c t pha ngoi hnh lang i li. - Theo s liu cho
th p lc bn ngoi ln nht l 6 (m) rt nh so vi p lc yu cu cho vic cp nc
cha chy cho ngi nh 6 (tng). V vy ta khng th dng nc cp trc tip t mng
li cp cho cha chy m ta phi dng bm cha chy.
- Chn h thng cp nc cha chy trc tip mi tng hai vi v nc c a ln bng
hai ng ng. Dng vi cha chy bng vi trng cao su c chiu di l 20 (m). -
Theo quy phm vi bnh vin c khi tch ln hn 2500 m3 th ta c s vi hot ng
ng thi l 2 vi v lu lng ca mi vi l 2.5 (l/s).
* Tnh ton- Theo s khng gian ta chn tuyn bt li nht l tuyn tnh ton
v chia tuyn nay thnh 2 on: on 1 lu lng l 2.5 l/s, on 2 lu lng l
5m/s
a. on 1 - Cn c vo lu lng ca vi l 2.5 (l/s) ta chn ng ng c:D = 50
(mm), i = 0.085, v = 1.274 (m/s).- Theo quy phm hp cha chy t cao
1.2( m) so vi sn nh.
+) Chiu cao ng ng ca h thng ng ng cp nc cha chy tnh t mc nc
trong b cha n vi cha chy bt li nht (cao nht) s l:
H = 3,5 x 6 + 1,2 + 6,3 = 28,5(m)
Tn tht ca 1 ng ng t trn mi xung s l:
h = 28,50,085 = 2,42 (m)+) Do trn h thng c ng ng dn ngang trn mt
t do vy s c thm tn tht trn on ng nm ngang. Tn tht trn on ng nm
ngang n 2 ng ng cha chy:
h1 = 200,085 = 1,7 m
(vi 2 m l chiu di on ng nm ngang n 2 ng ng cha chy)
-Tnh ton i vi on ng c 2 vi hot ng ng thi:
V s vi hot ng ng thi l 2 vi nn lu lng l 5 l/s. Tra bng tnh ton
thy lc chn D = 75 (mm), v = 1,3 (m/s) v i = 0,057 Tn tht trn on ng
c s vi hot ng ng thi l:
h2 = 9,50,057 = 0,54 m(vi 9,5 l chiu di ng tnh t my bm n on r
nhnh ca h thng cp nc cha chy)
Tng tn tht trn ton b h thng cp nc cha chy l:
Hl = h + h1 + h2 = 2,42 + 1,7 + 0,54 = 4,66 m
Tng tn tht p lc cc b h thng cp nc cha chy.
hcb = 10%Hl = 0,14,66 = 0,466 m
p lc cn thit u vo van cha chy:
hccct = hv + ho (m)
Trong :
hv: p lc cn thit u vi phun ta ra mt ct nc ln hn 7m p lc ny thay
i ty theo ng knh ming vi phun
ho: tng tht p lc theo chiu di ng vi gai c tnh theo cng thc
sau
Tnh h0
ho = Al(qcc)2 (m)
Trong :
A: sc khng n v ca ng vi gai c trng cao su ly nh sau
d = 50mm => A = 0,0075
l: chiu di lp vi gai (m), theo tiu chun ta ly l = 20m
qcc: lu lng ca vi phun cha chy 2,5 (l/s)
ho = 0,0075 x 20 x 2,52 =0,94 m
Tnh hv
hv : c th tnh theo cng thc sau:
hv =
Trong :
Cd : phn ct nc c tra ta ly Cd = 6
: h s ph thuc Cd v c ly theo bng Cd = 6 => = 1,19
: H s ph thuc vo ng knh ming vi phun
= khi tnh ton vi d = 13mm => = 0,0165
=> hv = = 6,8 m
hccct = 6,8 + 0,94 = 7,74m
Tng p lc cn tht ca ngi nh khi c chy xy ra l:
Hcc = H + Hl + hcb + hccct= 28,5 + 4,66 + 0,466 + 7,74 =41,4
m
Chn bm cha chy cho bnh vin vi q = 2,5 l/s v Hcc = 41,4 mVii. tnh
ton b cha - Dung tch b cha c xc nh theo cng thc:
Wbc=Wh+Wcc3h (m3)
Trong :
+ Wh: Dung tch phn iu ho ca b c tnh theo cu to, Wh = (1 (
2)(Qng. Chn Wh = Qng- y b cha ch phc v nc cho khu vc:Qng =
(m3/ng)
Trong :
+ N: L s ging bnh trong bnh vin, mi tng c 30 ngi bnh + ngi phc
vN = 6(30= 180 (ngi)
+ qo: Tiu chun dng nc hng ngy (ly theo ph lc) ca mt ging l
(l/ngy), q0 = 200 (l/ng.ng).
=> Qng = = 36 (m3/ng)
+ Wcc3h: L lu lng nc d tr cha chy trong 3 (h) cho mt m chy ca
ngi nh.
Wcc3h = 5(3(3000 = 45.000 (l/s) = 45 (m3)
=> Wbc = 45 + 36 = 81 (m3)
- Xy dng b hnh ch nht bng b tng ct thp, gch vi cc kch thc
sau:
L(B(H = 6,5x6,5x2phn ii: tnh ton mng li thot nc trong cng
trnh
I. Chn s thot nc trong nh- V h thng thot nc bn ngoi l h thng
thot nc chung nn tt c lu lng nc thi sinh hot t cc thit b v sinh u
thi chung ra ng thot nc sn nh ri ra ng thot nc thnh ph.
- V nh ln v yu cu cn x l cc b nc thi ln ta cho nc thi ca nh vo
ht b t hoi. Phn nc sau khi lng ht cn s ra ngoi cn phn cn s c gi li
nh vi khun ym kh phn hy.
- Nc thi c tp trung vo h thng thot nc sn nh c gn vo tng trong
tng hm sau a ra b t hoi.
- Cn nc ma c dn bng mt h thng ng ring. on ng thot cui cng ni vi
ng thot ca b t hoi. Sau i ra mng li thot nc thnh ph.
II. Vch tuyn mng li thot nc2.1.Tnh ton h thng ng ng v ng nhnh
cho cng trnh2.1.1. Vi mng li thot nc trong nh
- Da vo bng ng lng thot nc ta tnh tng ng lng cho tng ng nhnh, ng
ng cn c vo bng chn ng knh cho tng ng
- ng nhnh t cc thit b v sinh ly theo quy phm (bng 23.2 Cp thot
nc trang 295).Bng 4.Lu lng nc thi tnh ton ca cc thit b v sinh, ng
knh ng dn v dc tng ngTn thit bLu lng tnh ton (qtt), (l/s)ng knh ng
dn (d), mm dc ng dn, ( i )
Chu ra mt0,07500.02
Chu ra bp0,37500.025
X bt1,41000.02
Tiu0,5500,02
- ng nhnh dn nc thi t cc thit b v sinh u nh nhau trong tt c cc
tng do vy ta tnh 1 ng nhnh ri ly cc ng nhnh khc tng t.
- Cc ng nhnh t ngm trong sn nh vi dc tnh ton c th v gc ni vi cc
ng ng l 60o.
- ng nhnh t chu ra v x bt c chn su di nn vi su 10 (cm).*Tinh cho
ng ng T1(12 chu ra mt, 36 u tiu, 12 thng ra h x)Lu lng tnh ton: qtt
= qc + qdcmaxTrong :
+ qc: Lu lng nc cp tnh cho ca 6 tng
qc = 0,2.(. (l/s).Vi bnh vin ( = 1,4 N = 0,33 cho 1 chu ra mt N
= 0,17 cho 1 u tiu
N = 0,5 cho 1 x bt
=> N = 12x0,33+36x0,17+12x0,5=16,08 => qc = 0,2.1,4. =
1,12 (l/s).
+ qdcmax : Lu lng nc thi t thit b v sinh ln nht. y ta ly theo x:
qdcmax = 1,5 (l/s).
=> qtt = 1,5 + 1,12 = 2,62 (l/s).
Chn ng c ng knh D = 100 mm vi i = 0,03 , h/d = 0,62; v = 0,73
(m/s)
*Tinh cho ng ng T2(12 chu ra mt)Lu lng tnh ton:qtt = qc +
qdcmaxTrong :
+ qc: Lu lng nc cp tnh cho ca 6 tng
qc = 0,2.(. (l/s).Vi bnh vin ( = 1,4 N = 12 x 0.33 = 3,96 =>
qc = 0,2.1,4. = 0,56 (l/s).
+ qdcmax : Lu lng nc thi t thit b v sinh ln nht. qdcmax = 0,33
(l/s).
=> qtt = 0,56 + 0,33 = 0,89 (l/s).
Chn ng c ng knh D = 50 mm vi i = 0,02 , h/d = 0,62; v = 0,59
(m/s)*Tinh cho ng ng T3
(12 chu ra mt, 24 u tiu, 24 thng ra h x)Lu lng tnh ton: qtt = qc
+ qdcmaxTrong :
+ qc: Lu lng nc cp tnh cho ca 6 tng
qc = 0,2.(. (l/s).Vi bnh vin ( = 1,4 N = 0,33 cho 1 chu ra mt N
= 0,17 cho 1 u tiu
N = 0,5 cho 1 x bt
=> N = 12x0,33+24x0,17+24x0,5=20,04 => qc = 0,2.1,4. =
1,25 (l/s).
+ qdcmax : Lu lng nc thi t thit b v sinh ln nht. y ta ly theo x:
qdcmax = 1,5 (l/s).
=> qtt = 1,5 + 1,25 = 2,75 (l/s).
Chn ng c ng knh D = 100 mm vi i = 0,03 , h/d = 0,62; v = 0,73
(m/s)*Tinh cho ng ng T4
(6 chu ra bp) N = 1Lu lng tnh ton:qtt = qc + qdcmaxTrong :
+ qc: Lu lng nc cp tnh cho ca 6 tng
qc = 0,2.(. (l/s).Vi bnh vin ( = 1,4 N = 6 x 1 = 6 => qc =
0,2.1,4. = 0,69 (l/s).
+ qdcmax : Lu lng nc thi t thit b v sinh ln nht. y ta ly theo
chu ra bp 1 ngn: qdcmax = 0,37 (l/s).
=> qtt = 0,37 + 0,69 = 1,06 (l/s)Chn ng c ng knh D = 50 mm vi
i = 0,03 , h/d = 0,54; v = 0,7 (m/s) Bng 5: Bang tng hp tinh toan
thuy lc ng ng thot ncTTng ngS thit bNqc (l/s)qdcmax (l/s)qth (l/s)D
mmV (m/s)ih/d
Chu raChu ra bpTiuX
1T1120361216.081.121.52.621000.730.030.62
2T2120003.960.560.330.89500.730.030.62
3T3120242420.041.251.52.751000.730.030.62
4T4060060.690.371.06500.590.020.59
2.1.2.Vi mng li thot nc sn nh- Lu lng nc tnh ton cho tng on ng c
thc hin nh sau:
qth = qc + qdcmax (l/s)
Trong :
+ qth: Lu lng thot nc, (l/s).
+ qc: Lu lng nc cp, (l/s).
+ qdcmax: Lu lng nc thi ca thit b WC thi ra nhiu nc nht trong on
cng tnh ton (l/s)Bng 7. Bng tnh ton thu lc mng li thot nc sn nh
TN CNGCHIU DILU LNG NG KNH DCVN TC ViL Yh
L,ml/sD,mmim/smh/dm
G1-G222,63.511250.00720.70.160.430.05
G4-GT9,67.322000.00720.840.070.3220.06
CT T.CT T.CCT NH CNG.CT NH CNG.CCT Y CNG.CT Y CNG.C SU CHN CNG.
SU CHN CNG.C
7.27.26.656.496.66.440.60.76
7.27.26.496.426.436.360.770.84
2.2.Tnh ton cc cng trnh x l nc thi cc b - thot nc ra cng thot nc
thnh ph vi nc thi ra t thit b v sinh. Ta x l cc b bng b t hoi ri mi
thi ra mng li thot nc chung.
- Dung tch b t hoi xc nh theo cng thc sau:
Wb = Wn + WC (m3)
Trong :
+ Wn: Th tch nc ca b ly bng (1 ( 3) ln qthi ngy m.
+ Wb: Th tch ca b, (m3).
+ Wc: Th tch cn ca b, (m3).
2.2.1. Xc nh th tch nc ca b
Wn = k(Qng
Trong :
+ K theo quy phm ly t 1 ( 3. m bo hiu qu lng ta ly k = 2.
+ Qng: Lng nc thi ngy m.
Qng = q0(N (m3/ng)
Vi:
+ q0: Tiu chun thi nc, q0 = 150 (l/ng.ng) = 0.15(m3/ng.ng).
+ N: S ngi dng nc trong ngi nh, N = 180 (ngi).
=> Qng = 0.15(180 = 27 (m3/ng)
Vy: Wn = 2(27 = 54 (m3)
2.2.2. Xc nh th tch cn ca b
Wc = (N (m3)
Trong :
+ a: Tiu chun thi cn, Ly a = 0.7 (l/ng.ng).
+ T: Thi gian gia hai ln ly cn, T = 365 (ngy).
+ W1, W2: m ca cn ti vo b v ca cn khi ln men c gi tr tng ng
l:
W1 = 95%;W2 = 90%.
+ b: H s k n gim th tch cn khi ln men, gim 30% v ly b = 0.7.
+ c: H s k n vic li phn cn ln men khi ht cn gi li vi sinh vt gip
cho qu trnh ln men cn c nhanh chng, ly c = 1.2+ N: S ngi s dng.
Wc = (365 = 19,32 (m3)
- Vy dung tch b t hoi l:
Wb = Wn + Wc = 54 + 19,32 = 73,3 (m3)
- Chn 2 b kch thc ca mt b l : a ( b ( h = 5x4x2(m).
- Theo quy phm thit k b t hoi loi 3 ngn, dung tch ngn 1 bng 50%
v dung tch ngn 2 cn li mi ngn 25%. vch ngn ca b c b tr cc ca nh
sau:
+ Ca nc vo v ra khi b c ng knh: D = 100 (mm).
+ Ca thng cn c kch thc: 300(300 (mm).
+ Ca thng nc c kch thc: 150(150 (mm).
+ Ca thng kh c kch thc: 100(100 (mm).
+ Chiu cao ca thng nc: (0,4 ( 0,6)(H, Chn bng 0,5H.
2.3.Tnh ton thot nc ma trn mi nh2.3.1. Din tch phc v gii hn ln
nht ca mt ng ng
Fghmax = 20(d2( (m2)
Trong :
+ d: ng knh ng ng, chn D = 50 (mm) = 5 (cm).
+ vp: Vn tc ph hoi ca ng chn ng tn, vp = 2.5 (m/s).
+ (: H s dng chy, ( = 1.
+ h: Lp nc ma trong 5 pht ln nht khi theo di trong nhiu nm, theo
ti liu kh tng ca H Ni h = 15.9 (cm).
( Fghmax = 20(52( = 78.62 (m2)
- Din tch mi cn thot nc:
Fmi = 26x14+24x12-4,7x1,8 = 643,54(m2)
- S lng ng ng cn thit:
N = = = 8 (ng)
- Vy ta b tr 8 ng ng mi bn 4 ng v nh c chiu rng ln hn 12m2- Vy
din tch thc t phc v ca 1 ng l:
Fthc = = 80,44 (m2)
- Nc ma s c chy n ng ng vo h thng ng ng thot nc v vo h thng thot
nc ma sn nh v chy ra h thng thot nc ng ph
2.3.2. Tnh mng dn nc xn
- Kch thc mng dn xc nh da trn c s lng nc ma thc t chy trn mng dn
n phu thu v phi xc nh da trn c s tnh ton thc t.
- Lng nc ma ln nht chy n phu thu c xc nh theo cng thc:
q = (l/s)
Trong :
+ F: Din tch mi thc t trn mt bng m mt phu phc v, (m2)
q = (l/s)
- Chn mng dn ch nht bng b tng trt va, tra biu tnh ton thu lc Hnh
24.10 (Gio trnh Cp thot nc) c cc thng s k thut sau:
+ dc lng mng: i = 0.0044.
+ Chiu rng mng: B =20 (cm).
+ Chiu cao lp nc: H = 5 (cm).
2.4.Tnh ton thot nc ngoi sn nh- Nc ma bn ngoi sn nh c thot bng
rnh ch nht xy bng gch v c cc thng s k thut sau:
+ dc lng mng: i = 0.005.
+ Chiu rng mng: B = 30 (cm).
+ Chiu cao lp nc: H = 10 (cm).
~~~HT~~~ EMBED Equation.3
EMBED Equation.3
Nguyn Thu Hng _ 7153.5514
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