溢流壩段設(shè)計(jì)學(xué)習(xí)資料

1、溢流壩段設(shè)計(jì)一、孔口設(shè)計(jì)1、孔口形式本設(shè)計(jì)溢流壩段采用開(kāi)敞式溢流壩，孔口形式采用壩頂溢流式，堰頂不設(shè)閘門，所以溢流堰堰頂高程即為正常蓄水位605mo2、孔口尺寸本設(shè)計(jì)溢流堰凈寬51m,每孔凈寬17m二、溢流壩剖面設(shè)計(jì)溢流壩曲線由頂部曲線段、中間直線段和下部反弧段三部分組成，溢流面曲線采用WES曲線。1、設(shè)計(jì)依據(jù)溢洪道設(shè)計(jì)規(guī)范(SL253-2002)2、基本資料調(diào)洪演算成果匯總表工況上游水位(m下泄流量(m3/s)下游水位(m)正常605.00179.30572.83:設(shè)計(jì)609.451248.39576.29校核610.971831.76577.54有上述資料可得出Hmax=5.97m。3、溢

2、流曲線設(shè)計(jì)溢流曲線具體尺寸要求如下圖一所示，其中Hd為堰面曲線定型設(shè)計(jì)水頭設(shè)計(jì)水頭，規(guī)范要求按最大作用水頭Hmax的75%到95%計(jì)算，本設(shè)計(jì)采用80%倍的Hmax,所以Hd=4.78m。上游堰高P=42m>1.33Hd=6.35m,所以本設(shè)計(jì)為高堰流量系數(shù)md=0.502。1)、曲線上游圓弧段參數(shù)計(jì)算如下表所示:0.282Hd=1.348mR1=0.50Hd=2.39m0.276Hd=1.319mR2=0.20Hd=0.956m0.175Hd=0.837mR3=0.04Hd=0.191m曲線參數(shù)計(jì)算表0175HdF2=30.282Hd0.276HdR3=0.04Hd2)、下游曲線段下游

3、曲線段計(jì)算公式為：kHd式中：Hd為堰面曲線定型設(shè)計(jì)水頭；x,y為原點(diǎn)下游堰面曲線橫縱坐標(biāo)；n與上游堰坡有關(guān)；k當(dāng)Pi/Hd>1.0時(shí)，k值由規(guī)范查取，當(dāng)Pi/Hd三1.0時(shí)，k取2.0至U2.2上游堰坡垂直，所以由規(guī)范查的n=1.85;Pi/Hd=8.8>1.0，所以由規(guī)范查的k=2.0o綜上所述，本設(shè)計(jì)溢流堰堰面曲線段公式為：1.85Hd0.5經(jīng)excel計(jì)算可得堰面曲線計(jì)算表如下表所示x0.501.001.502.002.503.003.504.004.50ry0.0370.1320.2800.4770.7211.0101.3431.7192.137x4.004.505.00

4、5.506.006.507.007.508.00y1.7192.1372.5973.0983.6394.2204.8405.4996.1973)、中間直線段直線段與曲線段的切點(diǎn)計(jì)算如下所示：dy1.85x0.8510.85dx2Hd0.7代入數(shù)據(jù)計(jì)算可得：xt7.97myt6.154m4)、下游反弧段本設(shè)計(jì)采用挑流消能，由規(guī)范查的反弧段半徑R=(410)h。，式中h0為校核水位閘門全開(kāi)時(shí)挑流鼻坎反弧段最低點(diǎn)處的水深。挑流鼻坎高程取579.00m(下游最高水位577.54m)。反弧段最低點(diǎn)流速：v2gH式中：？為堰面流速系數(shù)，由長(zhǎng)江流域規(guī)劃辦公室提供的公式初步確定為：(10.055/ke0.5)

5、1/3(10.055/0.2778)1/30.93則v,.2gH00.93.29.81(610.97579)23.29m/s水深h1836.761.55mvB23.2951反弧段半徑R=(41O)ho,本設(shè)計(jì)反弧段流速為23.29m/s>16m/s,但流速也不是很大，同時(shí)考慮反弧段要與中間直線段相切，所以取R=6.42h0=9.95m綜上所述，溢流面初步擬定的剖面如下圖所示：堰頂高程605m鼻坎高程579m地基高程563m4、消能防沖設(shè)計(jì)本設(shè)計(jì)米用挑流消能，挑流鼻坎米用連續(xù)式鼻坎；挑射角規(guī)范要求在35?之間，本設(shè)計(jì)取挑射角B=30?反弧段半徑R規(guī)范要求取(410)為校核水位閘門全開(kāi)時(shí)挑流

6、鼻坎反弧段最低點(diǎn)處的水深；鼻坎高程規(guī)范下游最高水位12m,本設(shè)計(jì)下游最高水位577.54m,鼻坎高程取為579.00m。20?至Uh。，h0要求高于1）、挑射距離計(jì)算由于沖坑最深點(diǎn)大致落在水舌外緣的延長(zhǎng)線上，故跳射距離可按下式算:LvisincosgI22V1-3mn"Injcos式中:L為水舌挑射距離；V1為坎頂水面流速，按鼻坎處平均流速v的1.1倍計(jì)，即:1.1.2gH式中:H0為庫(kù)水位至坎頂?shù)穆洳?，？為堰面流速系?shù)；h1為坎頂平均水深在鉛直方向的投影，即h1=hcosB;h2為坎頂至河床面高差。由上面計(jì)算可得v=23.29m/s,所以Vi=1.1>23.29=25.62m

7、/s;hi=1.55cos9=1.34m;h2=579-563=16m;把這些數(shù)值代入挑射距離的計(jì)公式有：L=68.79m2）、沖坑深度計(jì)算最大沖坑深度的數(shù)值與很多因素有關(guān)，特別是河床的地質(zhì)條件，目前估算公式很多，設(shè)計(jì)規(guī)范推存按下式計(jì)算：tkq0.5H0.25式中:tk為沖坑深度；q為單寬流量；H為上下游水位差；a為沖刷系數(shù)根據(jù)規(guī)范本設(shè)計(jì)取為0.8。代入數(shù)值計(jì)算得：tk=11.54mL/tk=5.96>5,不會(huì)對(duì)壩體安全造成威脅所以滿足挑流設(shè)計(jì)要求。5、底孔設(shè)計(jì)底孔主要作為排沙孔，也有宣泄洪水、防空水庫(kù)的功能。底孔設(shè)在非溢流壩段，進(jìn)口中心線高程580.00m,空口尺寸3X3m。本設(shè)計(jì)底孔

8、為有泄進(jìn)水孔，包含進(jìn)口段、空身段和出口段。工作閘門布置在出口，閘門采用平板閘門。事故檢修閘門設(shè)在進(jìn)口段之后，檢修閘門也采用平板閘門。1）、進(jìn)口段進(jìn)口段曲線應(yīng)滿足下列要求：減小局部水頭損失，提高泄流能力；控制負(fù)壓防止空蝕。進(jìn)口曲線常采用1/4橢圓，其方程為：22xy_1A2（A）2橢圓長(zhǎng)軸（x軸）多與孔軸平行。對(duì)于矩形斷面的泄水孔的頂面曲線，A為孔高，a采用1/31/4；空口兩側(cè)壁曲線也用橢圓曲線，A為孔寬，a采用1/4;進(jìn)口段底部邊界線采用圓弧。進(jìn)口段的中心線，一般布置成水平。根據(jù)上述要求，進(jìn)口段頂面a取1/3，其曲線方程為：兩邊側(cè)壁的曲線方程為：22口90.56252）、空身段空身段采用圓形

9、斷面，直徑為3m。3）、漸變段本設(shè)計(jì)有壓泄水孔斷面為圓形，所以在進(jìn)口閘門后需設(shè)漸變段，以便水流平順過(guò)渡，防止負(fù)壓和空時(shí)產(chǎn)生。漸變段可采用在矩形的四個(gè)角上加圓弧的辦法過(guò)渡，本設(shè)計(jì)工作閘門不知在出口，所以在出口段也需要設(shè)置漸變段。漸變段工作復(fù)雜，不宜太長(zhǎng)，一般采用洞身直徑的1.52倍，邊壁收縮率在1:51:8之間。在壩身有壓泄水孔末端，水流從壓力流突然變成無(wú)壓流，引起出口附近壓力降低，容易產(chǎn)生頂部負(fù)壓，所以在出口常設(shè)1:101:5的斜坡，面積收縮率為0.850.90b根據(jù)上述要求，漸變段長(zhǎng)度取洞身長(zhǎng)度直徑的1.5倍，L=4.5m;邊壁收縮率1:8;出口段頂部設(shè)1:10的斜坡，面積收縮率為0.85。

10、6、水面線計(jì)算1）、堰頂部分壩頂頭部水面線坐標(biāo)X/Hd和Y/Hd可查水工設(shè)計(jì)手冊(cè)第六卷.泄水與過(guò)壩建筑物P6-181表27-2-5進(jìn)行插值計(jì)算。Hd=4.78m,H/Hd=1.25，具體計(jì)算過(guò)程如下表所示：Ls,isinX/HdY/HdXYH/Hd=1.00H/Hd=1.33-1-1.166-4.780-5.573-0.950-1.235:-0.8-1.153-3.824-5.511-0.940-1.221-0.6-1.141-2.868:-5.455-0.929-1.209-0.4-1.148-1.912-5.488-0.930-1.218-0.2-1.167-0.956:-5.577-0.

11、925-1.2440-1.0240.000-4.897-0.779-1.1030.2-0.8780.956:-4.195-0.651-0.9500.4-0.7541.912-3.605-0.545-0.8210.6-0.6252.868-2.988-0.425-0.6890.8-0.4853.824-2.318-0.285-0.5491-0.3244.780-1.549-0.121-0.3891.2-0.1475.736-0.7010.067-0.2151.40.0616.6920.2920.286-0.0111.60.2847.6481.3570.5210.20818029386041402

12、07790138壩頭部水面線計(jì)算表2）、直線部分的不摻氣水面線求解切點(diǎn)坐標(biāo)（Xt,Yt）已經(jīng)確定為（7.97,-6.154）。求曲線長(zhǎng)度Lc,t,查水工設(shè)計(jì)手冊(cè)第六卷泄水與過(guò)壩建筑物圖27-2-5,得Lc,t/Hd=2.08,所以Lc,t=9.94m。求直線段長(zhǎng)度Ls,從切點(diǎn)到直線上任意一點(diǎn)（Xi,yi）的距離計(jì)算公式為：式中:sin=0.82。從堰頂曲線起點(diǎn)到點(diǎn)（Xi,yi）的距離L=Lc,t+Ls,i。列表計(jì)算如下所示：計(jì)算邊界層厚度。公式為：YiYtsinaLs,iLc,tL6.156.150.820.00;9.94r9.9410.157.006.150.821.039.9410.970

13、.168.006.150.822.25:9.94M2.190.189.006.150.823.479.9413.41'0.1910.006.150.824.69:9.94:14.630.2111.006.150.825.919.9415.850.2212.006.150.827.139.9417.070.2413.006.150.828.3519.9418.290.2514.006.150.829.579.9419.510.2715.006.150.8210.79:9.9420.730.2816.006.150.8212.019.9421.950.3017.006.150.8213.2

14、3:9.9423.17:0.3118.006.150.8214.459.9424.390.3319.006.150.8215.67p.9425.6110.3420.006.150.8216.899.9426.830.3621.0016.1510.8218.109.9428.0410.3722.006.150.8219.329.9429.260.3922.836.150.8220.349.9430.280.400.02（一）0.1,式中K取0.45mmLK邊界層厚度計(jì)算表勢(shì)流水深hp試算，試算公式為：HYhpcos失算過(guò)程如下：對(duì)于每一個(gè)Yi,假定一個(gè)hp,通過(guò)計(jì)算得到另一個(gè)hp值，再將得到的數(shù)

15、值代入，依次進(jìn)行下去，直到獲得兩個(gè)相等的數(shù)值為止?，F(xiàn)以Yi=6.154為例，試算如下表所示：YihPhpA2*cosd(H+Yi)qA2/2ghp(H+Yi)hp差值6.1543.0000.4261.8082.2340.7666.1542.2340.2362.4282.664-0.4306.1542.6640.3362.0362.3720.2926.1542.37210.2662.2872.5531-0.1816.1542.5530.3092.1252.4330.1206.1542.4330.2802.2292.5101-0.0766.1542.5100.2982.1612.4600.0506

16、.1542.4600.2862.2052.492-0.0326.1542.492:0.2942.1772.471:0.0216.1542.4710.2892.1952.484-0.0146.1542.484:0.2922.1832.476:0.0096.1542.4760.2902.1912.481-0.0066.1542.4810.2912.1862.4780.0046.1542.478:0.2912.1892.480:-0.0026.1542.4800.2912.1872.4780.0026.1542.478:0.2912.1892.4791-0.0016.1542.4790.2912.1

17、882.4790.0016.1542.4790.2912.1882.4790.000勢(shì)流損失hp試算表由上表可以看出，Yi=6.154時(shí)，hp的試算結(jié)果為2.479。按照這樣的方法,最終的試算結(jié)果如下表所示：YihphpA2*cosc/(H+Yi)qA2/2ghp(H+Yi)hp6.152.4790.2912.1882.4797.002.3810.2512.1302.3808.002.2790.2132.0662.2799.002.1900.1842.0062.19010.002.1110.1601.9512.11111.002.0400.1411.9002.04012.001.9760.12

18、51.8521.97713.001.9180.111”1.807M.91914.001.8660.1001.7651.86515.001.8170.0901.7261.816116.001.7710.0821.6901.77217.001.7300.0751.6551.73018.001.6910.0681.6221.69119.001.6550.0631.591r1.654:20.001.6210.0581.5621.62021.001.5890.0541.5351.5882200155800501509155922.831.5350.0471.4881.535正交于壩面的壩面水深h=hp+

19、0.18S所以將上述計(jì)算綜合得出正交于壩面的壩面水深h如下表所示：Yihp0.18Sh6.1542.479r0.1460.0262.5057.0002.3800.1590.0292.4098.0002.279:0.1750.0322.3119.0002.1900.1910.0342.22410.0002.111:r0.2070.0372.14811.0002.040:0.2220.040r2.08012.0001.9770.2370.0432.01913.0001.919:0.2530.045r1.964"114.0001.865:0.2680.04811.91315.0001.81670.2830.0511.867”16.0001.7720.2980.054r1.825117.0001.