Experimental investigation of wave-driven pore-water pressure and wave attenuation in a sandy seabed

Jisheng Zhang,Cong Ding,Tiantian Zhang,Qianzhen Li,Jinhai Zheng

doi:10.1177/1687814016651207

Abstract

Wave–seabed interaction has become a big concern of coastal researchers and engineers in the past decades as it may largely contribute to the seabed instability and failure of marine foundations. A series of laboratory experiments are carried out in a wave flume to study the wave-driven pore-water pressure in a sandy seabed and the attenuation of wave height. Waves propagating over a sandy seabed lead to oscillatory excess pore-water pressures within the porous seabed. Amplitude of pore-water pressure within the seabed decreases toward the bottom. A phase lag of pore-water pressure is clearly observed, and it contributes to net upward pressure related to seabed instability. Height of the incident wave is reduced as part of wave energy is dissipated by bottom friction, and a maximum attenuation of the incident wave height is up to 7.23% in the experiments. The influences of wave period and height of the incident wave on pore-water pressure and wave attenuation are also analyzed and discussed.

Highlights

The problem of wave–seabed interaction has attracted more and more attentions of coastal researchers and engineers, as it plays an important role in the estimations of seabed stability and foundation design of offshore structures
This study is to experimentally investigate the mechanics of wave-driven pore pressure and the phenomenon of attenuation of water waves, and the influences of wave parameters on wave-driven pore pressure and wave damping in a sandy seabed will be studied
The interactions between the incident waves and a sandy bed are studied in terms of pore-water pressure, phase lag, and wave damping

Summary

Introduction

The problem of wave–seabed interaction has attracted more and more attentions of coastal researchers and engineers, as it plays an important role in the estimations of seabed stability and foundation design of offshore structures. Cheng et al.[8] studied the relationship between the distribution of pore pressure and bed profile change under breaking waves In their experiments, the net upward pore pressures were found to enhance the sand transport by reducing the effective weight of the sediment. This study is to experimentally investigate the mechanics of wave-driven pore pressure and the phenomenon of attenuation of water waves, and the influences of wave parameters (wave period and wave height) on wave-driven pore pressure and wave damping in a sandy seabed will be studied. A series of experiments are carried out in a wave flume (48 m long, 0.5 m wide, and 1 m high) for the investigation of wave–seabed interaction in a sandy bed.

Results and discussion

Conclusion

Declaration of conflicting interests