超校核洪水对某重力坝泄洪水力特性的影响研究  

Study on Impact of Over-Checked Flood on Hydraulic Characteristics of a Gravity Dam Discharge

作　　者：李山茂 张法星[1] 钟杰[1] LI Shanmao;ZHANG Faxing;ZHONG Jie(State Key Laboratory of Hydraulics and Mountain River Development and Protection,Sichuan University,Chengdu 610065,China)

机构地区：[1]四川大学水力学与山区河流开发保护国家重点实验室,成都610065

出　　处：《西北水电》2023年第3期63-70,共8页Northwest Hydropower

基　　金：国家自然科学基金项目(52192673)。

摘　　要：跌坎底流消力池在保证较高消能率的前提下,能够有效降低临底流速,因此,在多个高坝工程中得到应用。梯级水库群中设防标准较低的挡水坝一旦遭遇巨型地震或超标准洪水,存在溃坝风险,而溃坝洪峰流量一般会超过下游重力坝的校核流量。为了预测超校核洪水对重力坝跌坎底流消力池泄洪消能的影响,通过物理模型试验研究了重力坝在设计、校核洪水及超校核洪水泄洪时典型水力学参数的变化情况。结果表明:随着洪水流量增大,溢流坝面掺气空腔长度呈现先减小后趋于稳定的规律,反弧段脉动压强值和消力池前段纵向压强梯度都明显增加,尾坎下游平均波高增大,总消能率有一定的减小。研究结果可为重力坝枢纽工程设计及预防超标洪水提供参考。The use of stilling basin with step-down floor is a promising approach to reduce the velocity near the bottom at the downstream of the dam while maintaining a relatively high energy dissipation rate.This technique has been successfully applied in numerous high dam projects.In cascaded reservoir systems,low fortification standards implemented in dams can result in the risk of catastrophic dam failure during extreme events such as massive seismic events or floods exceeding check flood.In such scenarios,the peak flood flow rate resulting from dam failure often surpasses the downstream gravity dam's check flood.To assess the impact of over-checked flood on the stilling basin with step-down floor in a gravity dam,this study conducted physical model experiments to examine the changes of typical hydraulic parameters during the discharge of design flood,check flood,and over-checked flood.The findings indicate that the length of aerated cavity on the spillway decreases initially and stabilizes as the flood flow rate increases.In addition,the fluctuating pressure at the reverse curve section and the longitudinal pressure gradient at the front section of stilling basin both increases significantly.The average wave height downstream of the tail water increases,and the total energy dissipation rate decreases to some extent.The findings of this study can serve as a valuable reference for the design and prevention of over-level flood in gravity dam projects.

关 键 词：超校核洪水 重力坝泄洪 消力池 压强 水力特性 

分 类 号：TV65[水利工程—水利水电工程]