溃坝波冲击下的斜坡-平板结构压强时空分布

Temporal and spatial distributions of impact pressure on slope-deck structure under dam-break waves

水电站溃坝事故时有发生,因此研究溃坝波对下游结构物的冲击作用具有重要意义。本文开展物理模型试验,利用溃坝波生成器生成溃坝波,并记录水槽末端结构物受溃坝波冲击的力学表征。试验结果揭示了溃坝波冲击斜坡-平板结构时的荷载历时曲线及平板上托压强分布特性。在时间分布上,溃坝波冲击压强先后表现为5个压强阶段,本文主要研究其中的波前沿冲击压强及准恒定压强两阶段;在空间分布上,顺流方向的波前沿冲击压强和准恒定压强均从板坡结合处到板前沿递减,而在横流方向两压强变化均不大。基于试验数据拟合出溃坝波作用于平台的上托压强分布公式,得出顺流方向的最大波前沿冲击压强和最大准恒定压强分布情况。

Dam-break accidents occur at times at hydropower stations;dam-break waves often impose a significant impact on the downstream structures.In this work,physical model tests are carried out on a flume to record the mechanical characterization of a slope-deck structure,located at the end of the flume that is impacted by the dam-break waves created by a dam-break wave generating system(DWGS).We focus on analysis of the load history and distribution characteristics of uplift pressure on the structure during wave impacting.In time variation,the impact pressure shows five successive stages;the two stages of wave front impact pressure and quasi-constant pressure are examined in this paper.In spatial distribution,these two pressures decrease along the stream from the head to tail of the deck section,while they change little in the cross-flow direction.Based on the test data,a formula for calculating the platform uplift pressure distribution is fitted,and streamwise variations in the peak values of wavefront impact pressure and quasi-constant pressure are obtained.