带键槽透水底板脉动压力试验研究

消力塘防护结构是大坝安全的第一道防线，消力塘的安全是高坝泄洪安全的前提与保障。依托向家坝物理模型，以将“主动防护”与“被动防护”相结合的带键槽的透水底板为试验对象进行试验，主要针对带键槽透水底板的脉缝隙水流压力特性、下表面的脉动压力分布规律、时空相关性、空间相关性和压力频谱特性进行试验分析。结果表明，在水跃稳定区，增设透水孔后，带键槽底板下表面及垂直缝隙处各测点脉动压强最大值和脉动压强系数有所减小；带键槽底板下表面各测点间的相关性有所减小，同时涡漩的空间积分尺度与保持性减小；底板下表面及键槽处各测点的功率谱密度有所减小，并趋于低频。

Experimental studies of pulsating pressures on pervious base slab with keyway

The stilling basin protection structure plays as a first line of defense for dam safety, and the safety of the stilling basin and spillway becomes a safety premise of the dam. Based on the Xiangjiaba physical model, the model tests on the pervious base slab with keyway have been carried out in this study, in combination with "active protection" and "passive defense". And the characteristics of the pulsating water pressure from the groove, the distribution law of the pulsating pressure on the lower surface, the spatiotemporal correlation, the spatial correlation and the pressure spectrum characteristics of the pervious base slab with keyway are analyzed in this paper. The model tests results show that the the maximum values of the measured pulsation pressures on the lower surface and vertical groove of the pervious base slab with keyway have slightly decreased after addition of the permeable holes at the water jump stable region; the pulsation pressure coefficients measured at the measuring points located on the lower surface and the vertical groove of the pervious base slab with keyway have slightly decreased; the correlation between the measuring points located on the lower surface have also slightly decreased and at the same time the vortex space integral scale and maintenance have been reduced; and the power spectral density measured at the lower surface and the measuring points on the keyway has been reduced and it tends to have lower frequency.