Numerical Analysis on Liquefaction Countermeasure of Seabed under Submerged Breakwater using Concrete Mat Cover (for Regular Waves)

摘要

When the seabed around and under gravity structures such as submerged breakwater is exposed to a large wave action long period,the excess pore pressure is generated significantly due to pore volume change associated with rearrangement soil grains.This effect leads a seabed liquefaction around and under structures as a result from decrease in the effective stress,and the possibility of structure failure is increased eventually.These facts shown above have been investigated in the previous studies related to regular and irregular waves.This study suggested a concrete mat for preventing the seabed liquefaction near the submerged breakwater.The concrete mat was mainly used as a countermeasure for scouring protection in riverbed.According to installation of the concrete mattress,the time and spatial series of the deformation of submerged breakwater,the pore water pressure,and the pore water pressure ratio in the seabed were investigated.Their results were also compared with those of the seabed unprotected with the concrete mat.The results presented were confirmed that the liquefaction potential of seabed under the concrete mattress is significantly reduced under regular wave field.