带键槽透水底板上举力特性模型试验研究

为保护高坝下游河床和岸坡不受泄洪高速水流的严重冲刷,危及大坝安全,需修建各类消力塘防护结构以构建大坝安全第一道防线。各类消力塘防护结构的安全是高坝泄洪安全的前提保障。随着对高坝下游防护工程的研究不断深入,相继提出了带键槽消力塘底板、透水底板等不同结构形式的底板,增加消力塘的稳定性,消力塘形式也从"被动防护"模式向"主动防护"模式转变。对"主动防护"与"被动防护"相结合的带键槽的透水底板进行研究,通过模型试验从最大值、概率密度分布、幅值和功率谱等角度分析上举力的特性。结果表明,与带键槽的底板相比,增加透水孔可以降低上举力;上举力概率密度分布基本符合正态分布;上举力幅值降低;功率谱密度更加的趋近于低频。

Model Test on Uplift Force of Pervious Floor with a Keyway

To protect the downstream river bed and bank slope of the high dam from the serious erosion by high-speed flood flow, which will endanger dam safety, it is necessary to build all kinds of stilling pond protective structures as the first line of defense for dam safety. The security of all types of stilling pond protective structures is the premise for the safety of high dam flood discharge. As the studies on downstream protective works of the high dam dig deeper, floors of different structural forms have been proposed, such as the stilling pond floor with a keyway and the pervious floor, to increase the stability of the stilling pond. The form of the stilling pond also transformed from the "passive protection" model to the "active protection" model. This paper studied the pervious floor with a keyway that combines "active protection" with "passive protection". A model test was conducted to analyze the uplift force in terms of the maximum value, probability density distribution, amplitude, and power spectrum. The results showed: In comparison with the floor with a keyway, increasing permeable holes can reduce the uplift force. The probability density distribution of the uplift force basically conforms to the normal distribution. The magnitude of the uplift force is reduced. The power spectral density is even closer to a low frequency.