Stability of caisson-type breakwater foundation under tsunami-induced seepage

Numerical Analysis on Stability of Caisson-Type Breakwaters under Tsunami-Induced Seepage

“…The reduction of the effective stress is regarded as the reduction of the effective weight of the particle. It has been experimentally and numerically revealed that the hydraulic gradient was greater in the horizontal direction than the vertical direction [5,6]. Moreover, the light boiling has been observed, where the local hydraulic gradient exceeded the critical hydraulic gradient i cr [6].…”

“…It has been experimentally and numerically revealed that the hydraulic gradient was greater in the horizontal direction than the vertical direction [5,6]. Moreover, the light boiling has been observed, where the local hydraulic gradient exceeded the critical hydraulic gradient i cr [6]. Therefore, it can be assumed that the i cr is the appropriate index for the reduction of effective stress or the increase of excess pore water pressure.…”

“…For these problems, Takahashi et al [6] conducted lateral loading tests and finite element analysis for a caisson-type breakwater under seepage force. In order to evaluate the only effect of the seepage, the upward seepage was generated from the bottom of the container, and the component of uplift force was eliminated in the model test.…”

Prediction of Settling Velocity of Nonspherical Soil Particles Using Digital Image Processing

“…e DIP is a method to perform specific operations on digital images to extract information in digital images by computer algorithms. e DIP has been widely used to measure displacement and shape of particles in geotechnical engineering by many researchers [21][22][23][24][25][26][27][28][29][30]. e objective of this paper was to measure particle shape and settling velocity of nonspherical soil by DIP and develop the empirical prediction formula of settling velocity considering the particle shape and diameter.…”

Tsunami-Seabed-Structure Interaction From Geotechnical and Hydrodynamic Perspectives: Role of Overflow/Seepage Coupling

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This paper presents some recent research advances in tsunami-seabed-structure interaction following the 2011 Tohoku Earthquake Tsunami, Japan. Role of overflow and seepage coupling is highlighted, based on the effect of tsunami-induced seepage on piping/boiling, erosion and bearing capacity decrease and failure of the rubble/seabed foundation (Takahashi et al, 2014;Sassa, 2014;Sassa et al, 2016).A new tsunami overflow-seepage-coupled centrifuge experimental system was developed and applied such that the similitudes for tsunami overflow as well as turbulent seepage flows in the mounds were satisfied in addition to the mechanical similarity between the model and the prototype.The concurrent processes of the instability involving the scour of the mound/sandy seabed, bearing capacity failure and flow of the foundation and the failure of caisson breakwaters under the overflow and seepage coupling are elucidated in the paper. The experimental results first demonstrated that the coupled overflowseepage actions promoted the development of the mound scour significantly (Fig.

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