【设计洪水的计算过程案例2400字】

设计洪水的计算过程案例首先进行设计暴雨的推求，设计暴雨的分析计算方法应分为直接计算和间接计算两种。天目站流域内雨量资料有缺失值，不能全面反应整个流域，难以得到全面的面雨量系列来直接计算设计面暴雨量。故设计面暴雨量采用间接法来推求，第一步求出流域中心处的设计点暴雨量，然后再通过暴雨的点面关系将设计点暴雨量转换成设计面暴雨量。天目站流域设计暴雨计算时，按照三日暴雨进行设计。（1）计算设计点雨量查最大24小时雨量的均值X和24小时雨量CvH24=110mm，以及Cv=0.59，由公式计算某一频率设计值H24式中：Kp——模比系数，由CV=0.59、CS=3.5CV查P-Ⅲ型K再推求三天设计点雨量，可按下列公式计算H3p式中：H3pT——历时天数；m——常间段暴雨指数取0.24。（2）设计面雨量由设计点雨量推求设计面雨量，计算公式为：H式中：HmFHamK——折算系数设计面雨量计算结果见所示。表1.20设计雨量计算结果表pKPH24(mm)H3p(mm)KHmF(mm)2%3.3110364.2455.40.99448.90.33%4.91110541.2676.20.99668.70.10%5.9110639.1797.90.98783.1表1.21设计暴雨分配表时段雨量(mm)比例（%）P=2%P=0.33%P=0.1%123452.510.6161962.510.6161972.510.6161982.510.6161992.510.61619102.510.61619112.510.61619122.510.61619132.510.61619142.510.61619152086.2128.4153.2162086.2128.4153.2171564.596.3113.4181564.596.3113.4192.510.61619202.510.61619产流计算主要是水量损失的计算，本文将计算流域最大蓄水量Im的确定与前期影响雨量P（1）净雨量前期影响雨量：Pα式中：α——前期影响系数，查最大一、三、七天暴雨前期影响系数α值，暴雨量在250mm以上时，选取三天暴雨对应的α=0.6；Im——最大初损值，选取山丘区Im=60mm。查太湖区旱地次降雨径流关系曲线图，由于天目灌区的日暴雨量超过100mm很多，所以采用公式计算：R=(P+P式中：R—最大三天净雨量大小，mm；P—最大三天设计面雨量大小，mm；Pα表1.22设计净雨成果表保证率pPR2%428.6374.60.33%641.4587.40.10%761.2707.2设计净雨分配计算采用初损后损法求净雨深。计算总损失量：I=P−R=P−(P+计算初损值：I0计算后损值：I后根据暴雨分配过程，先扣除初损值，然后在产生净雨的时段内均匀扣除后损值，即得到净雨深。计算结果如表示。表1.23初损后损分析时段P=2%P=0.33%P=0.1%HI0I后h（t）HI0I后h（t）HI0I后h（t）1000000200000030000004000000511.311.3016.7516.75019.719.70611.311.3016.757.461.258.2419.664.51.8213.64711.31.71.967.8816.751.1614.6919.661.1217.74811.31.269.1816.751.1614.6919.661.1217.74911.31.269.1816.751.1614.6919.661.1217.741011.31.269.1816.751.1614.6919.661.1217.741111.31.269.1816.751.1614.6919.661.1217.741211.31.269.1816.751.1614.6919.661.1217.741311.31.269.1816.751.1614.6919.661.1217.741411.31.269.1816.751.1614.6919.661.1217.741589.81.2687.88133.31.16131.2156.61.12154.661689.81.2687.88133.31.16131.2156.61.12154.661767.41.2665.499.971.1697.91117.51.12115.541867.41.2665.499.971.1697.91117.51.12115.541911.11.269.1816.751.1614.6919.61.1217.742011.11.269.1816.751.1614.6919.61.1217.7421000220002300024000合计449.624.331.34397.06667.5424.2131.49613.36784.0424.231.5731.44表1.24单位线推求表t(h)t/KS(t)S(t-Δt)u(Δt,t)I=10F/3.6Δtq(Δt,t)(m3/s)00.00.00.00.0137.60.030.90.10.00.1137.610.361.80.30.10.2137.629.792.60.50.30.2137.632.5123.50.70.50.2137.625.3154.40.90.70.1137.619.1185.30.90.90.1137.68.3216.21.00.90.0137.65.8247.01.01.00.0137.63.3277.91.01.00.0137.61.5308.81.01.00.0137.61.0339.71.01.00.0137.60.83610.61.01.00.0137.60.03911.41.01.00.0137.60.04211.31.01.00.0137.60.04513.21.01.00.0137.60.04814.11.01.00.0137.60.05115.01.01.00.0137.60.05415.81.01.00.0137.60.05716.71.01.00.0137.60.06017.61.01.00.0137.60.06318.51.01.00.0137.60.06619.41.01.00.0137.60.06920.21.01.00.0137.60.07221.11.01.00.0137.60.0表1.252%标准单位线推求表推求标准P=2%，n=2.86，K=3.4t(h)q(t)部分径流QQ面h1h2h3h4h5h6h7h8h9h10h11h12h13h14(m³/s)6888888887876464880000310.4606629.8188026932.6222680561225.416292680791519.2132129268097188.441721292680105215.9361721292680110243.42461721292680113271.6134617212926870194301.111346172129249870418330.9111346172127324964064036001113461721327318564076839001113461612132021858078642001113469161157202268633450011132069119157292642448001112920521192129273510011142936521721171540017142136761710257006792146556000669342963005613156600511769001127200117500∑138.787117117117117117117117112811288568561181185110表1.260.33%标准下瞬时单位线及径流成果推求表推求标准P=0.33%，n=2.86，K=3.4t(h)q(t)部分径流QQ面h1h2h3h4h5h6h7h8h9h10h11h12h13h14h1581313131313131313128128979713130000310.3808629.82213035932.52343130791225.61946431301211518.314374643130153189.1724374643130170215.951224374643130180243.5371224374613130155271.61471224374343130184301.1124712244646431280313330.81124712373746374128064936001124724243740837497097939011241212243214082819701163420112771223132130428113011804501144711523124130443139644801224721151722414643698510112427284172374645754111184254842437262570011218315412241526009121331712846309813474166078242169071210720112750117800∑13910419019019019019020319019017301730129212921901908061表3-30.1%标准下单位线推求表推求标准P=0.1%，n=2.86，K=3.t(h)q(t)部分径流QQ面h1h2h3h4h5h6h7h8h9h10h11h12h13h14h1512181818181818181815215511311316160000310.312012629.83618054932.541521801111225.63356521801591518.322445652180192189.11232445652180214215.961632445652180224243.53111632445652180232271.627111632445652180238301.11471116324456521520375330.913471116324456445152077136002347111632444864451130116339023471116323824863321120138742023471116273382363331180141045