开敞式溢流堰水力计算

开敞式溢流堰水力计算开敞式溢流堰泄流能力计算公式：式子：Q—流量，m3/s；B—溢流堰净宽，m；Hw—堰顶以上作用水头，m；m—流量系数，见表C1（《混凝土重力坝设计规范》P71）；C—上游面坡度影响修正系数，上游面为铅直面时，C=1.0；ε—侧收缩系数，据闸墩厚度及墩头形状而定，ε=0.9~0.95；σs—淹没系数，视淹没程度而定，不淹没时σs=1.0。QCmεσsBHwHdHw/HdHmax0.0001.00.4260.931.0150.01.29601.629.3071.00.4260.931.0150.51.2960.38581.6212.2341.00.4260.931.0150.61.2960.4631.6215.4161.00.4260.931.0150.71.2960.54011.6218.8351.00.4260.931.0150.81.2960.61731.6222.4751.00.4260.931.0150.91.2960.69441.6226.3231.00.4260.931.0151.01.2960.77161.6229.5441.00.4260.931.0151.081.2960.83331.6229.4211.00.4260.931.0151.0771.2960.8311.6239.0171.00.4260.931.0151.31.2961.00311.6243.6041.00.4260.931.0151.41.2961.08021.6254.2761.00.4260.931.0151.621.2961.251.6263.2531.00.4960.931.0151.6211.2961.25081.62经水文计算：1、Q设=29.4m3/s；对应水位Δ=258.082、Q校=54.3m3/s对应水位Δ=258.623、堰顶高程：Δ=257.0。4、坝顶高程：Δ=260.0（反推计算得）2/32WsHgBCmQes=P（上游堰高）P/Hd64.629629664.629629664.629629664.629629664.629629664.629629664.629629664.629629664.629629664.629629664.629629664.629629664.6296296坝顶高程的确定坝顶计算公式：H=h静+ΔhΔh=hl+h0+hchl=0.0166V5/4D1/3L=10.4hl0.8基本数据设计洪水位校核洪水位258.08258.62多年平均最大风速V018.0012.00吹程假定DPi坝基高程hl波高0.5713409880.344176575L波长6.6458363794.430557586设计情况校核情况0.30.20ex7.66474E+124.56382E+19e-x1.30468E-134.71253E-20cth1.0001.001.025649890.63Hz波浪中心线高于静水位的高度0.1543089060.0839951290.1714023坝顶高程259.11259.25坝顶宽度12.00安全超高259.25工况3.141592654226.700.80260取两者较大值LHcthLhhzlpp22=一、基本数据尺寸数据其中：H1—设计洪水位与正常高水位，h1为相应下游水位。H2—较核洪水位，h2为相应下游水位。H3—泥砂淤积高程。H0—河床清基后高程。H—坝顶高程。YnnYmmb100.260.88地质数据其中：γ砂—泥砂干容重（KN/m3），空隙率ω，φ内摩擦角。L1—坝基帷幕灌浆距上游坝踵，L2—排水孔幕距坝锺，α—剩余水头系数。T—坝体计算断面沿上、下游方向的长度，m。地震设计烈度为6级。γ砂（KN/m3）γ砂（KN/m3）γ砼（KN/m3）γ水（KN/m3）ω砂6.51324100.35二、坝基面强度几抗滑稳定计算注：①a.重心位置于W1与W2之间。b.重心位置于W3与W1之间。②判断重心位置：T/2关系判断下游面b上游面17.25满足a21.8484.66③判断力矩的正（+）、负（-）④深水波、浅水波判断ΔH（坝高）λ（波长）设计33.36.65故，波浪压力按深水波计算W16393.60W27154.78W31302.94P1P2Q1376.53Q2542.89Q3510.76深、浅水波判断ΔH＞λ2/=3.352垂直力计算公式自重水压荷载浪压力Pk水重Pm1Pm235.13小计16316.63u13898.5u22143.54u3562.24u4120.48（1）抗滑稳定计算抗剪公式：Σ（W-U）ΣPfK［K］9591.87174389.860.40.871.05抗剪断公式：Σ（W-U）ΣPf＇C＇Ａ9591.8724389.8580.58590.0034.50（2）坝基面强度计算1.上、下游边界垂直正应力计算σyu—上游边缘垂直正应力（不计扬压力时）；σyd—下游边缘垂直正应力（不计扬压力时）；σyu＇—上游边缘垂直正应力（计扬压力时）；σyd＇—下游边缘正应力（计扬压力时）；a.考虑扬压力时（单位：KN，KN/m2）计算公式：Σ（W-U）=ΣVΣMTσyu＇σyd＇9591.8717-5232.2134.5251.65304.40b.不考虑扬压力时ΣWΣMTσyuσyd16316.631711868.8434.5532.78413.12可见，上游面为压应力，下游面计和不计扬压力均小于坝基允许压应力。考虑计与不计扬压力。因为，扬压力是一种可能存在而不一定存在的荷载，而且扬压力不是一个准确计算得值。泥砂压力扬压力6724.76合计16316.631、基本荷载组合（正常蓄水位）小计26TMTWySS=s（参阅《重力坝》潘家铮主编，P115）σ1u—上游边缘垂直正应力（计扬压力时）；σ1d—下游边缘垂直正应力（计扬压力时）；σ1u＇—上游边缘垂直正应力（不计扬压力时）；σ1d＇—下游边缘正应力（不计扬压力时）；a.计扬压力时，σ1u＇=σyu（1+n2）σ1u＇σ1d＇nσ1d＇=σyd（1+m2）261.72499.220.20b.不计扬压力时，σ1u=σyu（1+n2）-n2puσ1uσ1dσyuσ1d=σyd（1+m2）-m2pd541.54605.19532.78用重力法分析坝内应力步骤：（参阅《重力坝》潘家铮主编，P120）a.先计算上、下游边界垂直正应力σy，然后根据单元微分体的平衡条件依次计算剪应力τxy及水平正应力σx，最后计算主应力σ1，σ2；b.先计算上下游边界应力，然后计算内部各点的应力；c.先计算无扬压力情况，然后计算扬压力产生的应力，并予跌加。σy=a+bx（依据σy呈线性分布的假定）a=σyd=ΣV/T-6ΣM/T2b=12ΣM/T3a.（无扬压力情况）σyabΣVΣMσy=a+bx413.123.4716316.6311868.84X0.005.007.0010.00σy413.12430.46437.39447.80τxy3、坝体内部应力计算2.主应力计算HH0H1h1H2h2260226.7258.08238258.62238φff＇C＇L1L2180.40.585905.34逆时针+顺时针为-54921.0219246.3718427.864923.52251500.04012638.452404.835617.808521.567271.5267.2651978.0455.2091610.15（计算设计工况）8.59-2.6914.14水平力对坝底中心点力臂（m）力矩坝体剖面拟定10.463.7714.9215.7014.2429.4129.1692.72918005227.2483106588.845083.516483693.65892692092.0680223.22141006609.2483338574.161917.645083.52693.664389.86K［K］5.902.5~3.0σ抗压1850σ抗压1850考虑计与不计扬压力。因为，扬压力是一种可能存在而不一定存在的荷载，而且扬压力不是一个准确计算得值。3.0815.2515.922.4516.76092092.0697324.27mσyu＇σyd＇0.80251.65304.40σydpu＝P1pd=P2αγ（H1-H0）413.12313.80113.00219.66T34.5034.90534.16H3234.052αTT-L20.734.530.511868.84-5232.21开敞式溢流堰的堰面曲线计算一、堰顶下游段堰面曲线式中：Hd—定型设计水头，按堰顶最大作用水头Hmax的75%~95%计算K，n—与上游面倾斜坡度有关的参数，当上游面垂直，k=2.0，n=1.85X，Y—以溢流坝顶点为坐标原点的坐标，X以向下有为正，Y以向下为正。表一HmaxHdkn备注1.621.29621.85取Hmax的80%计1.621.21521.850.751.621.53921.850.95二、堰顶上游段堰面曲线上游坝面为铅直面，R1，R2，R3等参数见下表R1R2R30.76950.30780.061560.175Hd0.276Hd0.282Hd0.2690.4250.4341.539表二当下游面为铅直面时，堰顶下游堰面曲线为：x1.85=2.0Hd0.85yX00.20.40.60.8Y0.950.0000.0180.0640.1350.229Y＇0.95X0.0000.5001.0001.5001.300Y＇0.950.0000.3560.6410.9050.8019.557.16259.0725Hd7.5x0123456基本数据L（距原点水平距离）RiY＇0.95=0.5Hd-0.851.85x0.85=0.8(非溢流坝段下游坡斜率)Hd为1.539米，R1=0.5Hd，R2=0.2Hd，R3=0.04Hd堰面曲线ykHxndn)1(-=y0.000.090.330.691.171.772.48y'0.000.170.300.420.540.660.771/m1.282Hw0.51.01.52.02.53.03.5Hw/Hd0.0670.1330.2000.2670.3330.4000.467m0.4360.4360.4360.4360.4360.4360.446Hw/Hd0.40.50.60.70.80.91Hw/P0.4360.4510.4640.4760.4860.4940.501C1.000B24g9.8δs1ε0.936m0.4360.4360.4360.4360.4360.4360.446H0.511.522.533.5Q15.33143.36179.660122.644171.400225.312290.4370.1750.2760.282x1.31252.072.1150.50.20.04R3.751.50.3hpHyiqcosαhp1.02697.543.71432.30.61503181.19847640.1715764331.02681.18248970.1556896761.02671.16649820.1397982471.02661.15050210.1239021451.02651.13450140.1080013681.02641.11849590.0920959131.02631.10248580.076185781.02621.0864710.0602709671.02611.07045150.0443514711.0261.05442730.028427291.02591.03839840.0124984241.02581.0223649-0.0034351311.02571.0063266-0.019373375式中：Hd—定型设计水头，按堰顶最大作用水头Hmax的75%~95%计算K，n—与上游面倾斜坡度有关的参数，当上游面垂直，k=2.0，n=1.85X，Y—以溢流坝顶点