Abstract
There are both essentially saturated zone (the degree of saturation Sr ≅ 100%) and unsaturated zone in all of the exposed sandy beaches. This geo-environmental characteristics change drastically with a certain value known as the air-entry suction. In natural tidal flats, there are the essentially saturated zones in most of the exposed sediment deposits at the time of low tide, whereas in artificial tidal flats, they may contain unsaturated zones. From the viewpoint of the stability of coastal geo-environments and the conservation of rich ecosystems, it is important to identify the essentially saturated zone in sandy beaches and tidal flats. However, in order to accurately evaluate the zone, it takes time and labor, such as a careful sampling of sediments and laboratory tests of the sampled soils. In this study, focusing on a soil moisture sampler applying vacuum blood sampling, we proposed a new simplified method that can easily evaluate and verify the essentially saturated zone through laboratory performance tests and field surveys, and demonstrated the practicability and effectiveness of the new simplified method. From now on, it is expected that this new simplified method will be effectively utilized at the site.
