高坎下游泄洪常常采用水垫塘消能 ,挑跌水流可能对塘底产生巨大的冲击。如果底板止水破坏 ,冲击压力在缝隙中形成强烈的脉动压力是底板失稳破坏的重要因素。利用瞬变流理论 ,揭示了底板缝隙中脉动压力形成条件和传播特性 ,为进一步研究底板失稳破坏打下了基础 High ridge flood discharge downstream often use plunge pool energy dissipation, plunge the flow may have a huge impact on the bottom of the pond. If the floor water stop damage, the impact of pressure in the gap to form a strong pulsating pressure is an important factor in the instability of the floor. Using the theory of transient flow, the forming conditions and propagation characteristics of the pulsating pressure in the crack of the floor were revealed, which laid the foundation for further study on the failure of the floor.