PAGEPAGEXX鄉(xiāng)供水工程設(shè)計中洪峰流量的計算過程案例目錄TOC\o"1-3"\h\u26410XX鄉(xiāng)供水工程設(shè)計中洪峰流量的計算過程案例 132651.1鐵一院法計算洪水 173631.2水利科學(xué)研究院水文研究所公式計算洪水 2106501.3適線法計算洪峰流量 6202051.4設(shè)計洪峰流量計算成果分析 121.1鐵一院法計算洪水1.1.1適用范圍暴雨公式為西北各省還有流域面積小于100平方公里的小流域。1.2基本假定所有計算參數(shù)都與頻率沒關(guān)系，均取平均值。除了暴雨和跟暴雨有關(guān)的參數(shù)。最大同時期匯流面積不是線性分配。流域的部分面積同時匯流造峰是洪峰流量形成的主要途徑，全面積同時匯流造峰是本方法的一個特例。公式推導(dǎo)采用變動的徑流系數(shù)。1.3設(shè)計洪峰流量1.3.1已知的參數(shù)1.3.2設(shè)計洪峰流量計算（本計算所參考圖表都在《給排水設(shè)計手冊》）公式：計算過程：(P=2%)（1）查表2-9得η=1.0S=ηS=1.0×53.8=53.8(2)假設(shè)t＜1h，用n1計算流量(3)計算產(chǎn)流因子k1=0.278×53.8×1.59=23.78(4)計算損失因子k2=R·Sr1-1=1.1×53.80.76-1=0.42(5)計算主河槽匯流因子(6)計算山坡匯流因子(7)x=K1+0.95K2=0.62+0.95×2.34=2.843查2-14得y=0.432(8)當(dāng)k2=0.42，r1=0.76,查表2-15得Cn=1.18n’=Cn·n=1.18×0.7=0.826(9)K1+K2=0.62+2.34=2.96查表2-16得r=1.978(10)由r=1.978，n’=0.826查表2-17得：P1=0.294查表2-18得P=0.498(11)代入公式(2-50)得：=(12)按公式2-51進行驗算T=P1·Q-y=0.294×2.843×25.19-0.432=0.207小時＜1小時∴與假設(shè)相符，無需重新計算其他頻率的洪水計算同理，詳細(xì)結(jié)果見表3-41.2水利科學(xué)研究院水文研究所公式計算洪水1.2.1適用范圍流域面積小于500平方公里。全面匯流和部分匯流都可用。式子中的參數(shù)地區(qū)性明顯，使用時注意用本地區(qū)實測資料驗證。不適用于溶洞、泥石流及各種人為措施影響嚴(yán)重的地區(qū)。1.2.2基本假定匯流面積曲線概化為矩形。流域產(chǎn)流過程是降雨過程與損失過程的差值，而且匯流時間內(nèi)產(chǎn)生的徑流概化為強度不變的過程。1.2.3設(shè)計洪峰流量計算公式1.2.4計算步驟（1）根據(jù)流域資料確定以下參數(shù):1)流域參數(shù):流域面積F(公里2);主河槽長度L(米);主河槽坡降J02)暴雨參數(shù):雨力S;暴雨遞減指數(shù)n3)經(jīng)驗參數(shù):損失參數(shù)μ;匯流參數(shù)m0(2)計算和SpF值,然后由SF、τ0計算圖中查出τ0值，見附錄9。(3)計算值,查Ψ、τ計算圖確定ψ和值，見附錄10。(4)將已知ψ和τ代人公式中，即可算得設(shè)計洪峰流量Q值。1.2.5設(shè)計洪峰流量計算(p=2%)計算和SF：SF=53.8×1.59=85.542查附錄9,在縱坐標(biāo)上取SF,沿橫軸方向交直線,.再沿縱軸方向交到已知n值的線上,然后在右邊縱軸上讀出τ0值τ0=0.4小時。計算：查附錄10,由橫坐標(biāo)與n值查ψ值，再利用ψ-n-曲線簇，由ψ、n查得ψ=0.98=1.02將ψ、τ帶入公式得洪峰流量：=43.64（m2/s)其他頻率的洪水計算同理，詳細(xì)結(jié)果見表3-5。表3-4鐵一院法設(shè)計洪水成果表PF(k㎡)nSk1k2K1K2xyCnn′γP1PQ(㎡/S)2%1.590.753.823.780.420.622.342.8430.4321.180.8261.9780.2940.49825.195%1.590.743.219.10.450.622.342.8431.4321.1960.8371.9780.2830.48216.8710%1.590.735.115.510.470.622.342.8432.4321.2130.8491.9780.2640.45511.8020%1.590.727.011.930.500.622.342.8433.4321.240.8681.9780.2130.3777.3450%1.590.616.47.250.560.622.342.8434.4321.3050.7831.9780.3580.5842.51表3-5推理公式法設(shè)計洪水成果表PF(k㎡)L(m)JJ1/3nSμmSFΨQ(㎡/S)2%1.592.65117%0.490.753.81.110.18585.5421.180.8260.980.4080.5341.0243.645%1.592.65117%0.490.743.21.110.18568.6881.1960.8370.960.6240.7191.0425.5010%1.592.65117%0.490.735.11.110.18555.8091.2130.8490.960.7280.8011.0418.5920%1.592.65117%0.490.727.001.110.18542.9301.240.8680.970.8240.8731.0313.2650%1.592.65117%0.490.616.41.110.18526.0761.3050.7830.940.8480.9061.067.52 1.3適線法計算洪峰流量實測資料年n=2013-1965+1=49歷史考證期N=2013-1936+1=78計算經(jīng)驗頻率如表3-5。表3-5洪水經(jīng)驗頻率表序號洪峰流量（m3/s）17030.01325700.02513420.0200.0000.02523070.0400.0200.04532780.0600.0400.06542730.0800.0600.08552650.1000.0800.10562450.1200.0990.12471750.1400.1190.14481530.1600.1390.16491500.1800.1590.184101450.2000.1790.204111400.2200.1990.224121380.2400.2190.244131370.2600.2390.264141360.2800.2590.284151350.3000.2790.304161260.3200.2980.323171250.3400.3180.343181240.3600.3380.363191200.3800.3580.383201100.4000.3780.403211080.4200.3980.423221050.4400.4180.443231000.4600.4380.46324990.4800.4580.48325970.5000.4780.50326940.5200.4970.52227920.5400.5170.54228900.5600.5370.56229890.5800.5570.58230880.6000.5770.60231870.6200.5970.62232770.6400.6170.64233750.6600.6370.66234740.6800.6570.68235700.7000.6770.70236690.7200.6960.72137670.7400.7160.74138660.7600.7360.76139650.7800.7560.78140600.8000.7760.80141530.8200.7960.82142520.8400.8160.84143500.8600.8360.861用矩法計算統(tǒng)計參數(shù)。用式`X=。計算年最大洪峰流量的均值，式中N=78，n=49，a=2，l=1。得`X=126.80得：用式計算年最大洪峰流量的變差系數(shù)，得=0.84變差系數(shù)計算表X703332006.44570196426.2434246311.0430732472.0427822861.4427321374.4426519099.2424513971.241752323.24153686.44150538.24145331.24140174.24138125.44137104.0413684.6413567.241260.641253.241247.8412046.24110282.24108353.44105475.24100718.2499772.8497888.04941075.84921211.04901354.24891428.84881505.44871584.04772480.04752683.24742787.84703226.24693340.84673576.04663696.64653819.24604462.24535446.44525595.04505898.24528432.68219243.72選則理論的洪水頻率曲線。根據(jù)計算出的統(tǒng)計參數(shù)的結(jié)果，取，查表得出不同頻率P得值，列入表3-6。表3-6適線表頻率（％）第一次適線法`KpQp1230.018.8621123.700.16.528827.750.25.832739.500.335.338676.860.54.922624.1114.24537.6323.564451.9252.69341.09102.046259.43201.43181.32500.69688.25750.44456.30800.40851.73900.35645.14950.3443.11990.3341.84圖3-2洪峰流量頻率曲線圖將表中數(shù)據(jù)點繪成曲線，如圖3-2，此時的曲線和經(jīng)驗點距配合的相對較好，，所以可以作為采用的洪水頻率曲線，可得出本設(shè)計不同設(shè)計頻率P（2%、5%、10%、20%、50%）下的洪峰流量，表3-7洪峰流量表P=2%P=5%P=10%P=20%P=50%洪峰