水文频率适线法案例（目估）

主讲：马雪琴杨凌职业技术学院副教授

工程水文及水利计算年径流水文频率计算——水文频率适线法案例【例】某河某断面的流量资料见下表（单位m3/s)。试用适线法推求该站年径流量的频率曲线，并确定相应于频率为P=10%设计丰水年、P=50%设计枯水年、P=90%设计枯水年的设计年径流量。年份1956195719581959196019611962196319641965年径流量766.9346.4459.0627.9646.5516.5345.1581.3936.5289.6年份1966196719681969197019711972197319741975年径流量621.5581.8387.7660.3502.9497.1450.1682.3497.5365.1年份197619771978197919801981198219831984

年径流量582.0822.0500.6670.2466.1429.8406.8374.7413.2年份(m3/s)序号

①②③④⑤⑥⑦⑧1956766.91936.53.31.7600.7600.57761957346.428226.71.5450.5450.29701958459.03766.910.01.4420.4420.19541959627.94682.313.31.2830.2830.08011960646.55670.216.71.2600.2600.06761961516.56660.320.01.2410.2410.05811962345.17646.523.31.2150.2150.04621963581.38627.926.71.1800.1800.03241964936.59621.530.01.1680.1680.02821965289.61058233.31.0940.0940.00881966621.511581.836.71.0940.0940.00881967581.812581.340.01.0930.0930.00861968387.713516.543.30.971-0.0290.00081969660.314502.946.70.945-0.0550.00301970502.915500.650.00.941-0.0590.00351971497.116497.553.30.935-0.0650.00421972450.117497.156.70.934-0.0660.00441973682.318466.160.00.876-0.1240.01541974497.51945963.30.863-0.1370.01881975365.120450.166.70.846-0.1540.02371976582.021429.870.00.808-0.1920.03691977822.022413.273.30.777-0.2230.04971978500.623406.876.70.765-0.2350.05521979670.224387.780.00.729-0.2710.07341980466.125374.783.30.704-0.2960.08761981429.826365.186.70.686-0.3140.09861982406.827346.490.00.651-0.3490.12181983374.728345.193.30.649-0.3510.12321984413.229289.696.70.544-0.4560.2079合计15427.4

28.999-0.0012.3369解：①计算、点绘经验点②算绘理论频率曲线

由统计参数初值，均值=532m3/s，变差系数Cv=0.30，设偏态系数Cs=2Cv=0.60，作为初试值，查模比系数表，计算不同频率P相应的xP值并列表，绘制理论频率曲线，并与经验点进行拟合。m3/s③适线适线过程频率p(%)(1)12510205075909599第一次适线Cv=0.30,Cs=2Cvkp(2)1.831.711.541.401.240.970.780.640.560.44xp(3)973.6909.7819.3744.8659.7516.0415.0340.5297.9234.1Cv=0.30Cs=2Cv曲线中部偏于点上方曲线上下部偏于点下方③适线适线过程频率p(%)(1)12510205075909599第二次适线Cv=0.32,Cs=3Cv(采用)kp(4)1.961.811.601.431.240.950.770.640.580.48xp(5)1042.7962.9851.2760.8659.7505.4409.6340.5308.6255.4Cv=0.32Cs=3Cv适线结果

由曲线可以得出，频率10%、50%、90%对应