Review of Liquefaction Around Marine Structures by B. Mutlu Sumer

Owing to the growth of activities in the marine environment, the phenomenon of fluid–soil structures around marine infrastructures has attracted great attention among coastal and geotechnical engineers. Seabed liquefaction is one of the key failure mechanisms around marine installations such as breakwaters, pipelines, platforms, and offshore wind turbine foundations. Therefore, evaluation of the seabed instability around marine structures is particularly important for engineers involved in the design of foundations of marine infrastructures.

Overall, this is a comprehensive book describing the physics and processes of seabed liquefaction around marine structures. This book is particularly suitable for postgraduate students and academic researchers in the field. This book consists of 11 chapters plus four appendixes. The bulk of the main chapters can be grouped into three major parts, and the structure of each part is as follows.

Chapters 1–4 introduce the fundamental knowledge of the liquefaction processes, including a brief introduction to the physics of liquefaction due to waves and earthquakes (Chapter 1), the basics of Biot’s poroelastic theory and the corresponding analytical solution (Chapter 2), the residual mechanism (pore pressure buildup) (Chapter 3), and the oscillatory mechanism (momentary liquefaction) (Chapter 4). In this part, the author presents comprehensive analytical solutions from the research available in the literature, which is important for junior researchers in the field. Four appendixes are linked with these chapters. This part provides new researchers in the field of coastal geotechnical engineering with a clear picture and basic concepts of liquefaction in marine environments.

The second part (Chapters 5–9) further considers marine structures. Part of the contents presented in these chapters comes from the European Union project Liquefaction around Marine Strcutures (LIMAS) (2002–2004). In this section, floating and sinking of offshore pipelines are discussed in Chapters 5 and 6; liquefaction due to standing waves is presented in Chapter 7; liquefaction around gravity structures (e.g., composite breakwaters), with a specific focus on the effects of the rocking of breakwaters on residual liquefaction, is presented in Chapter 8; and the stability of rock berms with the aspect of seabed liquefaction is discussed in Chapter 9. This part is particularly useful for researchers and engineers who are working in the area of wave–seabed–structure interactions.

The third part (Chapters 10 and 11) covers earthquake-induced soil liquefaction (Chapter 10) and other marine infrastructures (Chapter 11). The last chapter (Chapter 11) briefly discusses several different marine installations and infrastructures other than the common coastal structures, including the design of a trench layer for buried pipelines, gravity-based structures (such as drainage pads, apron, and skirt), hydraulic fills, and steel sheet pile cofferdams.

Four appendixes are included at the end of the book, covering small-amplitude linear waves (Appendix A), soil properties (Appendix B), in situ relative density (Appendix C), and the coefficient of the analytical solution (Hsu and Jeng 1994, Appendix D). Appendices B, C, and D are useful for all readers with backgrounds in coastal or geotechnical engineering. Appendix A could be useful for geotechnical engineers, but is unnecessary for coastal engineers.

This book is largely based on the author’s recent work together with his peers’ work since the late 1990s on the topic of liquefaction. Minor components (parts of Chapters 1–4) were covered in the author’s previous book (Sumer and Fredsøe 2002, Chapter 10). However, Chapters 1–4 of this book provide much more detailed information than the previous book published in 2002. The content of the other chapters is not covered in the previous book. The major difference between the two books is that the earlier one focuses more on scour, whereas the present book focuses on liquefaction, and this is one of very few reference books on wave-induced liquefaction available in the literature.

The book contains a wealth of information on the mechanics of the liquefaction process with specific applications to marine structures. The author not only presents the research outcomes from his research group but also summarizes important results from other researchers including the partners in the LIMAS project, including the key results presented in two special issues on LIMAS published in the Journal of Waterway, Port, Coastal, and Ocean Engineering by ASCE (Sumer 2006, 2007).

A specific strength of this book is its focus on both fundamental knowledge and the recent advances in the models developed for the assessment of liquefaction. This could be the most updated reference book on liquefaction around marine structures. The only information missing from this book is information on three-dimensional models around marine structures, for example, breakwater heads, offshore wind turbine foundations, and so on, which have been considered in some recent publications.

Owing to the rapid development of offshore activities, marine geotechnics has become one of the hottest research topics in the disciplines of coastal and geotechnical engineering. Some universities have started offering master’s degrees in offshore geotechnical engineering. This is the first comprehensive book to address one of the most important issues, liquefaction, in the field of marine geotechnics for postgraduate courses. It is a good reference book on liquefaction that should be on the desk of postgraduate students, researchers, and engineers dealing with the design of foundations for marine structures.