截排水沟计算

四、截排水沟设计计算书采用公式为：当F＜3km2时Qp=φSpF式中：Qp——设计频率地表水汇流量（m3/s）φ——径流系数0.139Sp——设计降雨强度（mm/h）F——汇水面积（km2）排水沟过流量计算公式为：C=R1/6/n式中：Q——过流量（m3/s）R——水力半径i——水力坡降W——过流断面面积（m2）C——流速系数（m/s）n——糙率(浆砌块石)取0.017截水沟流量表编号渗流系数R20年暴雨强度Hn(mm/h)50年校核暴雨强度Hn(mm/h)汇水面积F(km2)废水流量(m3/s)设计流量Qb(m3/s)校核流量Q(m3/s)DE0.565.579.40.20.001.8212.207CD0.565.579.40.140.001.2751.545BC0.565.579.40.180.001.6391.987AB0.565.579.40.560.005.0996.180EF0.565.579.40.320.002.9133.532截水沟尺寸设计排水沟编号排水沟流量（m3/s）Q粗糙系数n(m)沟底坡度i沟壁边坡系数m设计沟底宽b(m)选定流量的正常水深h(m)水力半径R水流流速V设计排水沟流量Qo(m3/s)超高水深设计沟深H(m)设计结果校核设计结果DE1.8210.0170.310.50.40.40.1910.652.5560.300.70满足满足CD1.2750.0170.040.50.50.50.234.441.660.300.80满足满足BC1.6390.0170.330.50.40.40.1910.992.640.300.70满足满足AB5.0990.0170.230.50.60.60.2812.026.490.300.90满足满足EF2.9130.0170.110.50.60.60.288.314.490.300.90满足满足