特殊工况下平原感潮河网地区防洪(潮)排涝水闸的消能防冲设计—以上海市嘉宝北片区为例

Energy dissipation and anti-scour design for flood control ( tide) drainage sluice in plain tidal rivernetwork area under special conditions — taking Jiabao north area in Shanghai as an example

以上海嘉宝北片区排涝水闸的设计为例,分析该类水闸可能出现的各种运行工况及相应消能防冲设计。认为正常工况下过闸水流均处于高淹没度的堰流状态,闸下一般不会发生水跃现象,为非控制工况。研究分析了两类特殊工况下水闸消能防冲设计,认为第一类特殊工况发生的概率很低且历时较短,一般可不考虑此类工况。第二类闸室内外水头差较大时闸门长时间保持某一局部开度特殊工况下,一般认为:(1)应有临时应急措施控制过闸流量;(2)闸下消力池设计应注意消力池深度和长度(水跃长度)计算值与闸门相对开度、闸室上下游水头差、下游水深等主要计算参数并非线性相关,实际设计时应尽量对所有可能组合均进行计算;(3)闸下海漫长度和河床冲刷深度计算主要与过闸流量相关时,且过闸流量较大导致下游河道平均流速超出允许不冲流速时,建议过闸流量按下游河道允许不冲流速与相应过水面积的乘积选用,合理控制海漫和防冲槽设计尺寸。

Taking the design of the waterlogging sluice in the northern part of Shanghai Jiabao as an example,the various operating conditions and corresponding energy dissipation and anti-shock design that may occur in this type of sluice are analyzed.It is considered that the water flowing through the sluice under normal conditions is in a state of high flooding weir,and the water jump phenomenon generally does not occur under the sluice,which is an uncontrolled condition.The research analyzes the sluice energy dissipation and anti-shock design under the special conditions of the second category.It is considered that the probability of occurrence of the special conditions of the first category is very low and the duration is short.Generally,such conditions may not be considered.In the second type of gate,when there is a large head difference between indoor and outdoor water,the gate maintains a certain degree of local opening for a long period of time.Under special operating conditions,there should be temporary emergency measures to control the flow of the sluice.In the design of stilling basin under sluice,it should be noted that the calculated value of depth and length(hydraulic jump length)of stilling basin is non-linear related to the main calculation parameters such as relative opening of gate,head difference between upstream and downstream of sluice chamber,and water depth at downstream.In the actual design,all possible combinations should be calculated as much as possible.When the calculation of overburden length and bed scour depth under the sluice is mainly related to the discharge of the sluice,and the average velocity of the downstream channel exceeds the allowable non scour velocity due to the large discharge of the sluice,it is suggested that the discharge of the sluice should be selected according to the product of the allowable non scour velocity of the downstream channel and the corresponding overflow area,and the design size of the overflow and anti-scour channel should be reasonably controlled.