湿床涌波作用下漂砾运动过程试验研究  

Experimental study on the motion process of boulders under bores

作　　者：宁博雯 刘海江[1] NING Bowen;LIU Haijiang(College of Civil Engineering and Architecture,Zhejiang University,Hangzhou 310058,China)

机构地区：[1]浙江大学建筑工程学院,浙江杭州310058

出　　处：《海洋工程》2025年第1期166-175,共10页The Ocean Engineering

基　　金：国家自然科学基金资助项目(52071288,52271292)。

摘　　要：涌波冲击作用下的漂砾运动过程研究可用于估算相应极端海浪事件的水动力特征,为海岸带防灾减灾策略的制定提供参考。基于物理模型试验探究了湿床涌波冲击固定/运动漂砾过程中的冲击压强时空变化特征、水动力作用机理及漂砾的运动学特征。结果表明:固定情况下,涌波冲击压强在冲击瞬间即达到峰值,后呈现准静压状态逐渐下降;运动情况下,涌波冲击压强在漂砾发生运动后快速下降,而后保持准静压状态并缓慢降低。冲击作用过程中,冲击力几乎在涌波冲击漂砾瞬时即达到峰值。固定情况的冲击力在达到峰值后缓慢降低;运动情况的冲击力在漂砾运动后快速下降,后保持相对稳定,直至冲击过程结束。具体到不同的冲击力组分,惯性力仅在冲击的初始阶段起作用,在漂砾运动后可忽略不计;静水压力随漂砾处水位的抬升而增加,后保持相对稳定;拖曳力是涌波冲击作用过程中最重要的水动力组分,其变化趋势与总水动力最为接近。试验中漂砾的运动模式仅为滑动,同时伴随轻微的摆动。漂砾运动过程中,经历加速、相对匀速和减速3个阶段,漂砾相对匀速运动的时间恰好为涌波水动力保持相对稳定的时段。Research on the motion process of boulders impacted by bores can be used to estimate the hydrodynamic characteristics of corresponding extreme wave events,providing a reference for disaster prevention and mitigation strategies in coastal zones.Through physical model experiments,this study investigated the spatiotemporal variation of impact pressure,hydrodynamic mechanisms,and kinematic characteristics of boulders under the influence of bores,considering both fixed and moving conditions.The results show that in the fixed condition,the impact pressure from the bore reaches its peak immediately upon impact,then gradually decreases,approaching a quasi-hydrostatic state.In the moving condition,the impact pressure rapidly decreases after the boulder starts moving,and then slowly declines in a quasi-hydrostatic state.During the impact process,the impact force peaks almost instantly when the bore strikes the boulder.In the fixed condition,the impact force slowly decreases after peaking,while in the moving condition,the impact force declines rapidly after the boulder starts moving and remains relatively stable until the end of the impact process.In terms of the force components,inertial force is only significant at the initial impact stage and becomes negligible after the boulder begins to move.Hydrostatic pressure increases as the water level around the boulder rises and then stabilizes.Drag force is the most significant hydrodynamic component during the bore impact process,and its trend closely follows that of the total hydrodynamic force.The boulder's motion was characterized solely by sliding,with slight oscillation.The boulder experienced three stages during its motion:acceleration,relative uniform motion,and deceleration.The period of relative uniform motion coincided with the phase where the bore hydrodynamics remained relatively stable.

关 键 词：溃坝 湿床涌波 漂砾运动 冲击压强 受力分析 

分 类 号：TV139.2[水利工程—水力学及河流动力学]