Abstract
There is currently little information about the physical properties of coarse sand beach habitats for organisms. To elucidate the physical properties of the shoreline areas of sandy beaches, the saturation level using glass beads of an equivalent particle size was measured using suction. The sediment hardness was also measured using three different instruments to examine the basic physical properties in shoreline areas of sandy beaches, especially coarse sand. Suction values, increase as the particle size is decreases. Three different hardness indexes indicated that glass beads with a grain size of more than 1 mm have the same nature as a gravel. Where the grain size of the glass beads was less than 0.5 mm, penetration resistance was connected with a decline of the saturated water level and correspondingly increased. Where the grain size of the glass beads was less than 0.7 mm, deep vane shear was connected with a decline of the saturated water level and correspondingly increased. Where the grain size of the glass beads was less than 1mm, vane shear was connected with a decline of the saturated water level and correspondingly increased. These results indicate that there is a difference in processes corresponding with the shift of the physical nature from gravel to sand based on the grain size of sand equivalence.