沙质岸坡上波浪传播变形及动力响应特性研究

Characteristics of wave propagation deformation and dynamic response on sandy shore slopes

波浪作用对水库岸坡稳定性有重要影响。为了解波浪在岸坡地形中的传播演变机制和孔隙水压力响应特性,在波浪水槽末端铺设长6 m、坡度1∶16的斜坡沙床进行试验。通过改变入射波浪参数,测量斜坡段各处波面形态,采集斜坡段不同位置处孔隙水压力,分析了波浪在沙质岸坡上浅水变形区域内波面变化特征、波能演变规律以及岸坡土体孔压特征。结果表明:随着入射波浪厄塞尔数的增大,波浪浅水变形更加明显,波形不对称性加剧,各阶谐波之间互相作用更加强烈;水深较大区域,岸坡渗透作用大于浅水变形作用,波高呈现减小趋势;浅水变形剧烈区,浅水变形作用大于岸坡渗透作用,波高呈现增大趋势,最终破碎;孔压随入射波高与波周期的增大而增大,岸坡不同位置处孔压沿深度衰减速率和随波高增长速率均不同;岸坡孔压沿深度衰减速率与入射波周期呈现出正相关关系,与波高并无太大关系。

wave action has an important effect on the stability of reservoir bank slope.In order to understand the evolvement mechanism of waves propagation in bank slope topography and pore water pressure response characteristics,a slope sand bed with a length of 6 m and a slope of 1∶16 was laid at the end of the wave flume for experimental test.By changing the incident wave parameters,the wave surface morphology was measured and the pore water pressure was collected at different positions in the slope section.The waves characteristics in the shallow water wave deformation area on the sand slope were analyzed,and the wave evolution law and bank slope soil pore water pressure response law were obtained.The experimental results show that with the increase of the incident wave Ursell number,the wave shallow water deformation becomes more obvious,the waveform asymmetry becomes more serious,and the interaction between harmonics becomes more intense.In the region with a large water depth,the slope permeability is greater than the shallow water deformation,and the wave height decreases.In the area of severe shallow water deformation,the effect of shallow water deformation is greater than that of slope infiltration,and the wave height increases,and finally breaks.The pore pressure increases with the increase of wave height and wave period.The attenuation rate of pore pressure along depth and the high growth rate of wave are different at different positions of bank slope.The attenuation rate of pore water pressure along the bank slope is positively correlated with the incident wave period,but not with the wave height.