生物洞穴对黄河口土样扰动试验研究

A Laboratory Study of the Simulated Burrows Disturbance of the Sediments of Yellow River Estuary

生物洞穴对潮滩沉积物扰动的影响研究越来越受到海洋沉积学、海洋生物学、海洋地质学等学科交叉的重视,并影响潮滩沉积物侵蚀的细观机理。室内土柱试验制备了有生物洞穴和无生物洞穴扰动土样,模拟了波浪作用下土样的孔隙水压力的变化,并对这2种土样进行了基本的物理力学性质测定和冲刷试验。结果表明:生物洞穴形成的优势通道,使其孔隙水压力累积值小于无生物洞穴扰动土样,其表层的含水量和黏粒含量比无生物洞穴扰动土样大。当冲刷流速大于土样泥沙起动流速时,有生物洞穴扰动的土样比无生物洞穴扰动土样更容易被冲刷。但当冲刷流速增大到一定值时,有生物洞穴扰动土样与无生物洞穴扰动土样的抗冲刷性能又趋于一致,因此生物洞穴的存在将影响海岸侵蚀过程。

The effects on the stability of intertidal sediments disturbed by zoobenthos have been concerned by marine sedimentology, marine biology and marine geology in interdisciplinary field. The bioturbation impacts micro mechanism of the sediment erosion. The soils with burrows and without burrows were made on the soil column tests in a laboratory. The pore water pressure under simulated wave was recorded in the experiment procedure. The basic physical and mechanical properties of soil samples and anti-erosion coefficient of soil samples were measured. The results showed that burrows formed preferential flow channel. The preferential flow channel caused that its pore-water pressure was smaller than that of the soil samples without burrows. The water content and the clay content of soil samples with burrows were bigger on the surface layer than that of the soil samples without burrows. When the erodible velocity was greater than the velocity that sediment started to move, the soil samples with burrows were easier erosion than the soil Samples without burrows. However, when the velocity increased to a certain value, the two soil samples had the similar anti-erosion characteristics. Therefore, the burrows would impact the coastal erosion process.