Numerical study on static and seismic stability of breakwaters on soft granular marine deposits against deep failure

• Published in: Marine georesources & geotechnology Vol. 35; no. 1; pp. 42 - 51
• Main Authors: Veiskarami, Mehdi, Neshaei, Mir Ahmad Lashteh, Karimpour Fard, Mehran, Pourramezan, Tina
• Format: Journal Article
• Language: English
• Published: Philadelphia Taylor & Francis 02.01.2017; Taylor & Francis Ltd
• Subjects: breakwater; Failure; Geoengineering; sand; Sand & gravel; Seismic engineering; Shear stress; stability; stress characteristics method
• ISSN: 1064-119X; 1521-0618
• DOI: 10.1080/1064119X.2015.1099063

Marine structures which cover a wide range of offshore and onshore structures are often subjected to different external and internal forces against which a proper design should be performed. Among many, breakwaters constructed over a relatively loose agglomerate of granular soils are much prone to deep seated failure extended beneath the foundation. This type of failure has been given less attention in conventional design approaches. Stability analysis of such failures is the main subject of this research which includes both the static and the seismic stability of breakwaters over granular marine soils. As the subsoil strata in sea beds often comprise loose sand deposits, it is more convenient to assume a rather small angle of dilation, at least at failure, which certainly reduces the potential to resist geotechnical instabilities. The method of stress characteristics along with slight modifications to handle this issue has been used to assess the overall stability of breakwaters against deep seated failures. Investigations revealed that while even under static condition, there is certain potential of failure, under seismic condition, the risk is quite very high. A series of design charts are also developed presenting the factor of stability as a measure of safety against such failure.