Measurements and modeling of swash-induced pressure gradients in the surface layers of a sand beach
Measurements and modeling of swash-induced pressure gradients in the surface layers of a sand beach
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沙滩表层冲刷引起的压力梯度的测量和建模
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
T. Mason
中科院分区：
文献类型：
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作者：
T. Baldock;A. Baird;D. Horn;T. Mason
提出了沙滩表层中冲刷引起的水力（压力）梯度的现场测量，并与一维扩散模型进行了比较。该模型描述了穿过多孔、准饱和沉积物的流动，并由海滩表面随时间变化的冲刷深度驱动。现场测量大致显示了四种不同类型的压力传播行为，这些行为似乎取决于斜流区的跨岸位置。通常发现海滩表层内的水力梯度比潮汐引起的地下水流可能产生的水力梯度大得多。在这些情况下，扩散模型通常可以很好地描述数据。然而，在海滩表面下方经常观察到非常大的水力梯度，并且这些不能通过扩散模型充分描述。提出了一种可以产生这些大水力梯度的机制。
Field measurements of swash-induced hydraulic (pressure) gradients in the surface layers of a sand beach are presented and compared to a one-dimensional diffusion model. The model provides a description of flow through a porous, quasi-saturated sediment and is driven by the time-varying swash depth on the beach surface. The field measurements broadly show four different types of pressure propagation behavior, which appear dependent on cross-shore position in the swash zone. The hydraulic gradients within the surface layers of the beach are typically found to be much greater than those likely to be generated by tidally-induced groundwater flow. In these instances the diffusion model generally provides a good description of the data. However, very large hydraulic gradients are frequently observed just below the beach surface, and these cannot be adequately described by the diffusion model. A mechanism is proposed through which these large hydraulic gradients could be generated.