溢洪道設(shè)計(jì)實(shí)例

1、溢洪道設(shè)計(jì)實(shí)例黑龍江農(nóng)墾林業(yè)職業(yè)技術(shù)學(xué)院1、進(jìn)水渠進(jìn)水渠是將水流平順引至溢流堰前。采用梯形斷面，底坡為平坡，邊坡采用1：1.5。為提高泄洪能力，渠內(nèi)流速<3.0m/s，渠底寬度大于堰寬，渠底高程是360.52m。進(jìn)水渠斷面擬定尺寸，具體計(jì)算見(jiàn)表1。表1水位（mm）泄量（m3/s）H(m)B(m)計(jì)算公式（假設(shè)=2m/s）設(shè)計(jì)校核363.62364.815408003.14.2982.486.7Q=A, A=(B+mh)hA過(guò)水?dāng)嗝娣e；B渠底寬度由計(jì)算可以擬定引渠底寬B=90米（為了安全）進(jìn)水渠與控制堰之間設(shè)20米漸變段，采用圓弧連接，半徑R=20m，引渠長(zhǎng)L=150米。2、控制段其作用是

2、控制泄流能力。本工程是以灌溉為主的小型工程，采用無(wú)閘控制，溢洪道軸線(xiàn)處地形較好，巖石堅(jiān)硬，堰型選用無(wú)坎寬頂堰，斷面為矩形。頂部高程與正常蓄水位齊平，為360.52m。堰厚擬為30米（2.5H<<10H）?？矊捰闪髁糠匠糖蟮茫唧w計(jì)算見(jiàn)表2。表2(忽略行近水頭2/2g)水 位(m)泄 量（m3/s）H0(m)計(jì)算公式及符號(hào)意義b(m)設(shè)計(jì)洪水位363.625403.1 式中m流量系數(shù)，等于0.364；H0堰上水頭，不包括行進(jìn)水頭；Q泄量；b控制堰寬。61.56校核洪水位364.818004.2956.02由計(jì)算知，控制堰寬取b=65m為宜。3、泄槽泄槽是渲泄過(guò)堰洪水的，槽底布置在基巖

3、上，斷面必須為挖方，且要工程量最小，坡度不宜太陡。為適應(yīng)地形、地質(zhì)條件，泄槽分收縮段、泄槽一段和泄槽二段布置。據(jù)已建工程擬收縮段收縮角=12°，首端底寬與控制堰同寬，b1=65m,末端底寬b2擬為40m，斷面取為矩形，則漸變段長(zhǎng)，取整則L1為60m，底坡。泄槽一段上接收縮段，下接泄槽二段，擬斷面為矩形，寬b=40m，長(zhǎng)L2為540m，底坡。泄槽二段斷面為寬40m的矩形，長(zhǎng)L3為80m，底坡。4、出口消能溢洪道出口段為沖溝，巖石比較堅(jiān)硬，離大壩較遠(yuǎn)，采用挑流消能，水流沖刷不會(huì)危及大壩安全。5、尾水渠其作用是將消能后的水流，較平穩(wěn)地泄入原河道。為了防止小流量產(chǎn)生貼流，淘刷鼻坎，鼻坎下游設(shè)

4、置長(zhǎng)L=10m護(hù)坦。1、溢流堰泄流能力校核：當(dāng)引渠很長(zhǎng)時(shí)，水頭損失不容忽視。（1）基本公式如下：； ； ； 。式中，hj局部水頭損失，米； hf沿程水頭損失，米； 局部水頭損失系數(shù)； 引渠流速，m/s；g重力加速度（m/s2）; L引渠長(zhǎng)度，米；動(dòng)能系數(shù)，一般為1.0； C謝才系數(shù)；R水力半徑，米； A過(guò)水?dāng)嗝婷娣e，米2；x濕周，米； n引渠糙率；式中，淹沒(méi)系數(shù)，取1.0； 無(wú)坎寬頂坎的流量系數(shù)；b 堰寬，m； H0包括行近流速水頭的坎上水頭，m；Q流量，m3/s。求堰前水深和堰前引水渠流速采用試算法，聯(lián)立公式可求得，具體計(jì)算見(jiàn)表1。表1計(jì)算情況泄量QH0h假設(shè)試算設(shè)計(jì)水位校核水位363.62

5、364.815408002.993.892.783.622.02.32.062.32由計(jì)算表中流速可知，均小于3m/s，滿(mǎn)足要求。求引渠總水頭損失。， ， ；式中）。具體計(jì)算成果見(jiàn)表2。表2計(jì)算情況hhjAxRnLhf設(shè)計(jì)校核2.783.622.02.30.200.270.020.027261.79345.46100.02103.052.623.353.615.010.0160.0161501500.0370.0350.0570.062作出庫(kù)水位流量關(guān)系。 庫(kù)水位=堰頂高程+堰上水頭+水頭損失，具體計(jì)算見(jiàn)表3。表3Q(m3/s)H0(m)(m)堰頂高程（m）庫(kù)水位(m)5406508002.9

6、93.143.890.0570.0620.062360.52360.52360.52363.567363.722364.4722、溢洪道水面曲線(xiàn)計(jì)算（1）基本公式如下：；式中 hk臨界水深，m； b泄槽首端寬度，m；Q槽內(nèi)泄量，m3/s； g重力加速度，m/s2;q單寬流量，m3/s.m; ik臨界坡降； BK相應(yīng)臨界水深的水面寬，m；AK,XK,RK,CK臨界水深時(shí)對(duì)應(yīng)的過(guò)水?dāng)嗝娣e（m2）、濕周（m）、水力半徑（m2）、謝才系數(shù)。E1+iL=E2+hf; ；式中 E11-1斷面的比能，m；E22-2斷面的比能，m；h1，h21-1及2-2斷面水深，m；1-1及2-2斷面平均流速，m/s；hf

7、沿程水頭損失，m；iL1-1及2-2斷面的底部高程差，m；L斷面間長(zhǎng)度，m；n泄槽糙率；兩斷面間平均流速，m/s；兩斷面間平均水力半徑，m。（2）漸變段水面線(xiàn)計(jì)算臨界水深hk及臨界底坡ik漸變段首端寬b1=65米，尾端寬b=40米，斷面為矩形。具體計(jì)算見(jiàn)表4表4計(jì)算情況QBKqKhKAkxkRKCK設(shè)計(jì)水位校核水位54080065658.3113.311.922.49124.8161.8568.8469.981.812.3169.0071.860.002180.00204漸變段，故屬陡坡急流， 槽內(nèi)形成b型降水曲線(xiàn)。屬明渠非均勻流計(jì)算。漸變段水面線(xiàn)計(jì)算首端斷面水深為臨界水深hk，具體計(jì)算見(jiàn)表5

8、。表5計(jì)算情況Qh1q1A1x1R1V1E1i1設(shè)h2q2A2設(shè)計(jì)水位校核水位5408001.922.498.3113.31124.8161.8568.8469.981.812.314.334.942.883.740.020.022.753.513.520110140X2R2V2E2I2LnhfE1+ilE2+hf45.5472.422.994.915.713.985.160.020.022.050.584.605.3060600.0160.0160.120.124.084.944.105.28由計(jì)算得漸變段末端水深分別為h設(shè)=2.75米，h校=3.5米(3) 泄槽一段水面線(xiàn)計(jì)算匯槽一段斷面為

9、矩形，寬40m，長(zhǎng)540m，臨界水深hk和臨界坡降ik具體計(jì)算見(jiàn)表6。表6計(jì)算情況QBKqKhKAkxkRKCK設(shè)計(jì)水位校核水位540800404013.5202.653.44106137.645.346.882.342.9472.0174.810.002140.00205，故泄槽一段屬急流，按陡槽計(jì)算。泄槽一段末端水深（正常水深h0）采用試算法。具體計(jì)算見(jiàn)表7表7計(jì)算情況Qbi設(shè)hoA0X0R0C0設(shè)計(jì)水位校核水位54080040402.032.681.210444.0645.21.842.369.4971.817619.8311326.15539800.88經(jīng)試算，設(shè)計(jì)水位時(shí)，h0=2.0

10、3米 ; 校核水位時(shí)，h0=2.6米。泄槽一段水面線(xiàn)計(jì)算采用分段求和法，按水深進(jìn)行分段，具體計(jì)算見(jiàn)表8。(4)泄槽二段水面線(xiàn)計(jì)算泄槽二段斷面為矩形，寬40m，長(zhǎng)80m，底坡。表8計(jì)算情況斷面h0(m)A(m2)V(m/s)V2/2g(m)Es(m)Es(m)X(m)R(m)L(m)設(shè)計(jì)水位1-12.651065.091.323.970.0145.32.3472.010.0022030.0027973.583.582-22.601045.191.373.9845.22.371.810.020.00250.0025811.583-32.45985.511.554.0044.92.1871.170.

11、060.0030440.00145630.6742.254-42.30925.871.764.0644.62.0670.50.010.0037500.0012580122.255-52.15866.282.014.1644.31.9469.80.130.0045670.000433300.23422.286-62.0381.26.652.264.2944.061.8469.19校核水位1-13.51405.711.675.1660.003472.9874.970.0020880.0029121.031.032-23.351345.971.825.16946.72.8774.500.0240.0

12、024050.0025959.2510.283-33.201286.251.995.19346.42.7674.020.0750.0028630.00213735.1045.384-43.001206.672.275.268462.6173.330.1350.0035320.00146891.96137.345-52.81127.142.605.40345.62.4672.600.2160.0044310.000569379.61516.956-62.61047.693.025.61945.22.3071.81求臨界底坡ik，控制斷面水深ho(正常水深)。因泄槽二段同泄槽一段流量、形狀、斷面尺

13、寸相同，故臨界底坡和臨界水深不變。設(shè)計(jì)水位時(shí)，ik=0.00214；校核水位時(shí)，ik=0.00205。，屬陡坡急流，按陡槽非均勻流計(jì)算?？刂茢嗝嫠頷0用試算法，具體計(jì)算列于表9。表9計(jì)算情況Qbi設(shè)hoA0X0R0C0設(shè)計(jì)水位校核水位54080040400.760.9630.438.441.5241.920.730.9259.3461.591541.172268.59545802經(jīng)試算，設(shè)計(jì)水位時(shí)，h0=0.76米 ; 校核水位時(shí)，h0=0.96米。泄槽二段水面線(xiàn)計(jì)算泄槽二段首端控制水深，設(shè)計(jì)水位時(shí)h=2.03米；校核水位時(shí)，h=2.6米。采用分段求和法計(jì)算水面曲線(xiàn)，具體計(jì)算見(jiàn)表10。 表中

14、僅推到泄槽二段末端，若推到正常水深時(shí)，陡槽長(zhǎng)已超過(guò)設(shè)計(jì)長(zhǎng)度，這是不切實(shí)際的。故泄槽二段內(nèi)不產(chǎn)生正常水深。由計(jì)算知末端水深在設(shè)計(jì)水位時(shí)為h=0.93米 ;在校核水位時(shí)為h=1.29米。表10計(jì)算情況斷面h(m)A(m2)V(m/s)Es(m)Es(m)X(m)R(m)L(m)設(shè)計(jì)水位1-12.0381.26.654.2860.28144.061.8469.200.0058380.1191622.362.362-21.85747.304.56743.71.6968.230.360.0077500.117252.995.353-31.70687.944.91743.41.5767.360.760.0

15、108540.1141466.2711.624-41.50609.05.63343.01.4066.071.1690.0167890.10821110.8022.425-51.305210.386.80242.61.2264.611.9830.0279060.09709420.4242.846-61.104412.278.78542.21.0462.942.8960.481990.07680137.7180.557-70.9337.214.5211.68141.860.8961.28校核水位1-12.61047.695.6190.32445.22.3071.810.0056720.119328

16、2.722.722-22.4968.335.94344.82.1470.960.4740.0074080.1175924.036.753-32.2889.096.41744.41.9870.050.6850.0099130.1150875.9512.704-42.08010.07.10244.01.8269.050.9970.0136850.1113158.9621.665-51.87211.118.09943.61.6567.951.4730.0196370.10536313.9835.646-61.66412.509.57243.21.4866.732.2400.0294870.09551

17、323.4559.097-71.45614.2911.81242.81.3165.361.7420.0417460.08325420.9280.018-81.2951.615.5013.55442.581.2164.53（5）溢洪道水面曲線(xiàn)成果及護(hù)砌高度計(jì)算溢洪道水面線(xiàn)是為確定邊墻高度、邊墻及襯砌底板的結(jié)構(gòu)設(shè)計(jì)和下游消能計(jì)算提供依據(jù)。溢洪道邊墻高度計(jì)算公式為：式中 h不摻氣時(shí)水深，m；hb當(dāng)流速大于78m/s時(shí)摻氣增加水深，m；安全超高，設(shè)計(jì)時(shí)取1.0，校核時(shí)取0.7, m；H邊墻高度，m。邊墻高度計(jì)算引水渠邊墻高見(jiàn)表11表11(v<78m/s) 參 數(shù)情 況h(m)(m)H=h+(m)

18、設(shè)計(jì)水位校核水位2.783.621.00.73.784.12控制堰邊墻高度與引渠等高。設(shè)計(jì)水位時(shí)，邊墻高度H=3.78米；校核水位時(shí)，邊墻高度H=4.12米。收縮段邊墻高度具體計(jì)算見(jiàn)表12。收縮段最大流速v=5.71米/秒<78米/秒，不考慮摻氣所增加水深，故H=h+。泄槽一段邊墻高度具體計(jì)算見(jiàn)表13。泄槽二段邊墻高度具體計(jì)算見(jiàn)表14。表12計(jì)算情況斷面斷面距漸變斷首端距離（m）計(jì)算水深h(m)超全超高（m）邊墻高度H（m）設(shè)計(jì)水位首端尾端0601.922.751.01.02.923.75校核水位首端尾端0602.493.50.70.73.194.20表13計(jì)算情況斷面斷面距離槽首端距離

19、（m）計(jì)算水深h(m)流速v(m/s)(m)(m)H(m)設(shè)計(jì)水位1-12-23-34-45-56-603.5811.5842.25122.25422.282.752.602.452.302.152.031.01.01.01.01.01.03.753.63.453.33.153.03校核水位1-12-23-34-45-56-601.0310.2845.38137.34516.953.53.353.203.02.82.66.677.147.690.200.200.70.70.70.70.70.74.24.053.93.73.73.5表14計(jì)算情況斷面斷面距離槽首端距離（m）計(jì)算水深h（m）流速v

20、(m/s)(m)(m)H(m)設(shè)計(jì)水位1-12-23-34-45-56-67-702.365.3511.6222.4242.8480.552.031.851.701.501.301.100.936.657.307.949.010.3812.2714.520.1350.1350.1350.1350.1350.1351.01.01.01.01.01.01.03.032.992.842.642.442.242.07校核水位1-12-23-34-45-56-67-78-802.726.7512.7021.6635.6459.0980.012.62.42.22.01.81.61.41.297.698.339.091011.1112.514.2915.500.200.200.200.200.200.200.200.200.70.70.70.70.70.70.70.73.53.33.12.92.72.52.32.19(6)出口消能計(jì)算溢洪道出口消能計(jì)算的任務(wù)是：估算下泄水流的挑射距離；選擇挑