Research on productive environment and effective use of lowland area near Ariake shallow sea

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To clarify the phenomena of resuspension and transport of the bottom sediment in shallow sea area, the velocity distribution and the bottom shear stress under combined wave and current condition were analyzed theoretically by a three-layer time invariant eddy viscosity model. Both the failure of bottom mud surface layer and the process of bottom mud resuspension were found to be dependent strongly on the bottom mud movement.The relative Importance and contribution of swelling and dispersion to the hydraulic conductivity of high swelling bentonite and low swelling Ariake clay under various Na-Ca mixed solutions were investigated. The average conductivity for the bentonite mixture was found to decrease drastically and finally become less than 1cm/day and that for the Ca-saturated Ariake clay mixture being also found to decrease during the distilled water leaching.The stabilized box foundation (SBF) method was found to decrease the settlement by 1/2 of that of the slab foundation from the in-situ model tests on the paddy field in Shiroishi town, Saga Prefecture. This effect was also made sure by the F.E.M analysis. Then the SBF was designed to construct for the structure of the JA Shiroishi Rice Seedling Center and confirmed the effectiveness to decrease the settlement.The travel resistance of the rubber crawler during driving was analytically simulated by using the deformation phenomenon of the rubber crawler due to the vertical load of the track rollers. This simulation method was found to be applicable to predict travel resistance by the rolling resistance of the track roller and to estimate the rolling resistance for each track roller arrangement