2007 年 54 巻 p. 1166-1170
In an area of Buzen Sea intertidal flat, multi-bar-trough structure is developed in both cross-shore direction with a long interval and along-shore direction with a short interval. We carried out geophysical investigation and geotechnical soil tests along the multi-bar-trough structure, and clarified that the softness and the density are closely related to the ground surface profile and water/groundwater level during a period of exposure. Relatively denser and stiffer sedimentary structures at bar regions are consistent with our explanation on the formation mechanism; i. e. denser and stiffer structures are explained as a consequence of accumulated contraction caused by effective stress associated with suction corresponding to a low groundwater level at 0.2 to 0.3m deep from the ground surface during the period of exposure.