ABSTRACT In this study, a series of hydraulic model tests with movable seabed was carried out to investigate the dynamic interactions between water waves and seabed soil in front of vertical breakwater. The results show that the typhoon wave nonlinearity, movable seabed induced wave damping, and wave period can affect the dynamic stresses in seabed soil. The seabed soil at standing wave anti-node is subjected to uniform stresses and has similar stress path as in fluid in shallow depth. The stress path at deeper depth can be treated as soil behavior in undrained condition.
INTRODUCTION The dynamic behavior of seabed under wave actions is a very important marine geotechnical engineering problem on the analysis of nearshore coastal structure stability. Many researches had been done all around the world were focused on the mechanism of wave induced seabed liquefaction, scour and shear stress failure, and several evaluation methodologies also had been established (for example, Jeng, 1997; Zen et al., 1998; Mostafa et al., 1999; Sassa and Sekiguchi, 1999; Jeng et al., 2001; Sumer et al., 2001; Kumagai and Foda, 2002; Jeng, 2003). However, most of studies are based on semi-static theory, and cannot be fully applied on the essentially dynamical interaction in practice. In order to investigate the dynamic interactions between water waves and seabed soil in front of vertical breakwater, this study set up and accomplished out a series of hydraulic model tests with movable seabed. The soil dynamic stresses was analyzed and discussed.
The experiments were performed in the wave flume located in the Harbor and Marine Technology Center at Taichung, Taiwan. The wave flume is dimensioned with 100 m long, 1.5 m wide and 2 m high, and equipped with 2 viewing window sets with 15 m long. Fig. 1 shows the setup of the movable seabed model.