A small seepage could cause significant changes to the hydrodynamic gradient and further enhance the sediment incipient motion and scour. However, most previous studies either ignored the influence of seepage or only considered the upward seepage in the prediction of sediment incipient motion. In this paper, a modified Shields number considering the two-dimensional seepage was derived. The analytical solution and numerical model were used to analyse the influence of wave-induced seepage on sediment incipient motion. The results indicated that two-dimensional seepage promoted the sediment incipient motion near wave troughs and restrained it near wave crests. The influence of seepage on sediment incipient motion would be underestimated if the horizontal seepage force was ignored. Meanwhile, it was found that the lower water depth and saturation, higher wave height, shear modulus and permeability in $z$-direction would remarkably increase the seepage force and then enhance the mobility of seabed particles.

小的渗流可能会引起流体动力梯度的显着变化，并进一步增强沉积物的初始运动和冲刷作用。但是，大多数先前的研究在预测沉积物初期运动时要么忽略了渗流的影响，要么仅考虑了向上渗流。本文推导了考虑二维渗流的修正希尔兹数。运用解析解和数值模型分析了波浪引起的渗流对泥沙运动的影响。结果表明，二维渗流促进了波谷附近沉积物的初始运动，并抑制了波峰附近的沉积物。如果忽略水平渗流力，渗流对泥沙初发运动的影响将被低估。同时，发现较低的水深和饱和度，$ž$方向将显着增加渗透力，然后增强海底颗粒的迁移率。