液化土在波浪作用下的运动轨迹特征试验研究

ExperimentalStudy on the Trajectory Characteristics of Liquefied Soil Under Wave Action

海底液化后的土体会随着波浪波动,在对液化土波动进行理论描述或对结构物作用力进行计算时,需要液化土质点的波动速度或运动轨迹。本文利用波浪水槽试验,在Stokes波的作用下,观察获得了液化土体质点在波浪作用下的运动轨迹。观测结果表明,在液化深度不变时,液化土质点椭圆运动的水平向长轴和垂向纵轴均沿床面深度向下逐渐减小;随着液化深度向下发展,观测的液化土的固定层位处土体椭圆运动轨迹将增大。本文尝试利用Stokes波动理论分别计算上层水体质点和下层液化土质点的运动轨迹,将计算结果与试验观测结果比较发现,此简化的理论计算液化土波动轨迹的误差较大,所以应探讨更加适合的理论来描述液化土的波动。

The liquefied soil on the seafloor fluctuates with waves,when calculating the theoretical description of liquefied soil fluctuations or calculating the forces acting on structures,the velocity or trajectory of the fluctuation of liquefied soil mass point is required.This article uses the wave tank test,under the action of Stokes waves,the trajectory characteristics of liquefied soil mass point under wave action are obtained through observation of the side wall of the sink.Observation suggests that at the same liquefaction depth,the horizontal and vertical axes of the elliptical trajectory of the liquefied soil mass point gradually decrease along the depth of the bed.The same layer,with the increase of the depth liquefaction,the horizontal and vertical axes of the elliptical trajectory of the liquefied soil mass point gradually increase.This paper attempts to use the Stokes wave theory to calculate the trajectories of the upper water body mass point and the underlying liquefied soil mass point,respectively.Compared with experimental observations,it is found that this simplified theoretical calculation has a larger calculation error for the fluctuating trajectory of liquefied soil.