大中桥水文计算范本(修改后)1

烟蓬公路平畅河大桥水文计算书一、基本情况 1.平畅河位于蓬莱市境内，根据调查资料，桥位以上全部流域面积F总=251.7KM，汇水面积区域内水库控制汇水面积F库=83KM2，该河主流长度L0=24.5KM，桥位附近河床比降3.5‰，落差198米，河床质为中砂。斜交角度α=10.000度二、流量计算1.按汇水面积比例法考虑水库折减F=FK=水库控制面积1-0.3*(FK/F)=折减系数δ=1)流量模数公式Q100=1195.941854n*c*F2/3=考虑水库折减Q100=1077.6305622）山东省水文手册流量计算公式查图Ⅱ-1，n=c=m3/s3m/s2251.70830.901130Km22Km与径流系数、河长、集流流速有关的系数K=B=查图Ⅱ-2，暴雨参数A=20100logN=百年一遇，N=则雨力系数Sp=A+BlogN=120Q100=K*Sp*F2/3=考虑水库折减Q100=3）平均流量公式： Q100=2009.1823151810.419345m3/sm3/sF总==KP=251.70.4250.002.00（山区K=0.42丘陵区（中下游）0.42KM2L0=m3/s24.5KM10.27346939I=8.082Qcp=2.27*F2/3*B1/3*I1/4KP*QCP1376.516811m3/sm3/sm3/s331.69079774.15B=F总/L0=考虑水库折减Q100=1240.3417274）取均值，Q100=1376.1305452.按分段叠加法考虑水库折减水库外流域面积计算F-FK=水库溢洪Q100=1761)流量模数公式Q100=2/3251.7-83=168.7m3/s查图Ⅱ-1，n=c=3m/s〉m3/sKm21301077.630562则F外=168.70915.9349755n*c*F=叠加流量Q100=1091.93497533.采用设计流量Q=1078m/s三、设计水位及设计流速计算形态断面法设计水位：4.732桩号河床标高水深0+5.609000+4.084.7320.00+6.8943.4551.30+9.8483.4871.20+19.6963.2811.50+23.6351.8472.90+29.5442.0602.70+34.6482.8231.90+39.3922.1702.60+44.3162.2602.50+47.2711.0893.60+51.2102.3812.40+59.0882.6052.10+78.7852.4452.30+91.5872.2352.50+93.5571.5793.20+102.4201.4593.30+104.3902.2602.50+108.3292.3192.40+111.2832.2202.50+120.1473.7421.00+128.0253.4641.30+132.8894.7320.0合计m水力半径R=2.109m/s流速V=3.892mR2/3i1/2=流量Q=ωV=1070.7m3/s四、孔径计算取设计流量Qs=1078m3/s一）利用经验公式计算查表，稳定河段，K=1.河槽宽度公式Lj'=K(Qs/QC)nBc=108.831932孔径斜长Lj=Lj'/cosα=110.510842.单宽流量公式m3/sm 河床糙率m=1/n=平均水深水面宽度40过水面积河床比降I=△h0.0035湿周0.6391.2611.3482.1682.7792.2912.2362.5173.0582.9972.2392.2072.3922.8253.2132.8732.4432.4631.7511.1290.6342.8142.9549.8483.9395.9095.1044.7444.9242.9553.9397.87819.69712.8021.9708.8631.9703.9392.9548.8647.8784.864128.8091.7973.72513.2758.54016.41811.69110.60512.3949.03511.80517.63943.47130.6225.56528.4775.6599.6217.27415.5218.8943.084275.112平均水深hcp=平均单宽流量Qc=1.28-0.030.211.43-0.21-0.760.65-0.091.17-1.29-0.220.160.210.660.12-0.80-0.060.10-1.520.28-1.272.148.31128.813.603.0902.9549.8504.1925.9135.1614.7894.9253.1794.1457.88119.69812.8042.0768.8642.1273.9392.9568.9947.8835.027130.445mm3/smmOK!河槽宽度Bc=最大水深Hmc=0.840n=0.90mm稳定河段，水流压缩系数β=（Bc/hcp)0.06=1.27885991Lj'=Qs/(βQc)=101.376032孔径斜长Lj=Lj'/cosα=102.93992mmm，可以3.892Lj=m/s18.4961551墩宽b=mm1.20V桥=V槽=1.07059509拟建7-20米预制板桥，则桥下实有过水断面宽Lp=Bc-墩宽=m >132.8110.51084二）用过水面积（冲刷系数法）计算设计流速采用天然河槽平均流速，即Vs=挤束系数λ=b/l=0.06092563.892m3/sQm=140*3.892*2.14=压缩系数μ=1-0.375(Vs/Lj)=桥下毛过水面积ωq=11640.92109616m3/s冲刷系数P=Q/（Qmμ（1-λ））*V桥/V槽=Qs/(μ（1-λ）VsP)=其孔径B=140.00mωq/hcp=ωj=(1-λ）ωq=280.80m2Vq=0.5X(Qs/ωj+Vc)=3.86m/s五、桥面标高计算1、雍水高度2、波浪高度风速取W=η=0.0522桥前最大雍水高度ΔZ=η（Vq-Vch)=(0.010)浪程取L=m299.01m2m0.200Km20m/s0.410.27波浪高度H0=0.0166W5/4L1/3=取桥下浪高H浪=2/3*H0=3、桥面标高桥面横坡为I=m桥面宽B=桥下净空取桥面铺装厚度取横坡差Δh=I*B/2=板厚取Hmin=六、冲刷计算（一）一般冲刷1、 64-1修正式：平滩水位时河槽宽度B=20.4650.9m%mm46.50.50.177.282mmmm7.030桥面中心线标高：130.67m1.295/31/63/5单宽流量集中系数A=(B1/2/H)0.15=含沙量E取2、64-2简化式：天然状态下河槽流量Qc=0.860河槽平均水深H=河槽最大水深Hmc==2.136m3.60m河床泥沙平均粒径d=)/(Ed))8.0006.494hp=(((AQs/(μBc))X(Hmc/H)m1077.6建桥后桥下河槽宽度B2=m/s3河槽通过的设计流量Q2=Qs=m5.119m1077.63m/s3130.67hp=1.04(AQs/QC)0.9(Bc/((1-λ)μB2))0.66hmc=m3、取hp=5.806（二）桥墩局部冲刷按 65-1修正式：V=VZ=Ed1/6hp2/3 =4.233桥墩宽度B1=1.2mV0=0.0246(hp/d)0.14(332d+(10+hp)/d0.72)0.5=1.23215944V>V0V0'=0.462(d/B)0.06V0=0.63788650.63251523n=(V0/V)(0.25d^0.19)=Kη=0.8(1/d0.45+1/d0.15)=0.89946792Kζ=11.862m hb=KξKη1B10.6(V0-V0')((V-V0')/(V0-V0'))n=（三）总冲刷深度hs=mhp+hb=7.7m则一般冲刷线标高：-1.074最低冲刷线标高：-2.9m3.2-0.988mm（四）桥台冲刷计算： ht=P*【（hmc-h）*h/hmc+h】= 冲止标高H止=Hs-hs-2.5=h=2.140m