Special Issue on Liquefaction around Marine Structures

In geotechnical-engineering terminology, liquefaction refers to the state of the soil in which the effective stresses between individual soil grains vanish and the water-sediment mixture as a whole therefore acts like a fluid. Under this condition, the soil fails, therefore precipitating failure of the supported structure such as pipelines, breakwaters, seawalls, pile structures, sea barriers, and revetment systems.

Although a substantial amount of knowledge has accumulated on flow and scour processes around marine structures in the last decade or so (Whitehouse 1998; U.S. Army Corps of Engineers 2001; Sumer and Fredsøe 2002), comparatively little is known about the impact of liquefaction on these structures. The topic has received little coverage in recent research, which has substantially advanced the design of coastal structures but not the design of their foundations with regard to soil liquefaction.

The European Union (EU) supported a three-year (2001–2004) research program on $\mathbf{LI}$ quefaction around $\mathbf{Ma}$ rine $\mathbf{S}$ tructures (LIMAS 2004) (http://vb.mek.dtu.dk/research/limas/limas.html). The guest editor, B. Mutlu Sumer, was coordinator of this program. A consortium of 10 European institutions (universities, hydraulics and geotechnical-engineering laboratories, and consulting companies) undertook this program. The objectives of the program have been twofold: (1) to investigate potential risks for failure of structures caused by liquefaction; and (2) to prepare and disseminate practical guidelines (guidance for design and maintenance), to be developed from the present research and also considering all state-of-the-art knowledge.

The present volume and a follow-up one are a collection of fifteen papers and a technical note produced from the research undertaken in the LIMAS program. The papers in this volume summarize the results of experimental and theoretical investigations on the fundamental aspects of soil liquefaction around marine structures and focus on processes and benchmark cases. The follow-up volume (scheduled for the November issue) will include papers on various other aspects of soil liquefaction, including field investigation of momentary liquefaction and scour, momentary liquefaction and gas content, scour around piles in soil with liquefaction history, soil reaction in saturated sand under impulsive loads, development of a sampler for measurement of gas content in soils, and seismic-induced liquefaction around marine structures. The publication of this group of papers will disseminate the results of the LIMAS program worldwide, appealing to end users in consulting companies, contractors, governmental authorities and research entities at universities and research institutions within the coastal and offshore engineering and geotechnical and foundation engineering communities. The publication of this special issue is believed to have broad appeal worldwide and will also build content and create interest in this currently popular area.

The idea of publishing this special issue was first proposed in 2003, almost halfway through the LIMAS program. The guest editor contacted Dr. Zeki Demirbilek, the editor of the journal until November 2005, to determine the possibility of publishing a special issue in JWPCOE, that would discuss the subject by using papers essentially produced under the LIMAS program. The response from Dr. Demirbilek was positive. He added in his response that “The idea of developing special issues for JWPCOE was considered to be a splendid one, and I have obtained ASCE’s endorsement and support for it. ASCE will be encouraging editors to plan special issues as a way of building content and creating interest in particular disciplines that are either currently ‘hot’ or potentially growth areas for their journal.” On this premise, the guest editor started to organize what has become a three-year project, a project that included several components, ranging from collecting the papers to finding peer reviewers, collecting the review reports, completing reviews by carefully evaluating papers and the peer-review reports, making final decisions, and so on. During this process, the guest editor has had an enormous amount of support from many colleagues.

Dr. Demirbilek, in his capacity as editor of JWPCOE, has been extremely supportive. He has also helped the guest editor with those papers on which the guest editor was a coauthor; review of those papers was handled by Dr. Demirbilek. The guest editor greatly appreciates that assistance. The guest editor would also like to express his appreciation for the support of Professor Vijay Panchang, the present editor of JWPCOE.

The peer reviewers have been the key persons in the process of creating the special issue. Without their input, the present task would have been impossible. The guest editor is therefore grateful to all the reviewers for their invaluable contributions. In alphabetical order these persons are Professor H. G. B. Allersma (Delft University of Technology, The Netherlands), Dr. K. H. Andersen (NGI, Norway), Dr. N. Anderson (BP Inc., UK), Professor A. Ansal (Bogazici University, Turkey), Dr. P. Brunning (StoltOff-shore, Aberdeen, UK), Professor L. Cheng (The University of Western Australia), Mr. J. S. Damgaard (WorleyParsons, UAE), Dr. Z. Demirbilek (ERDC, USA), Professor S. Dey (IIT, India), Professor H. Gotoh (Kyoto University, Japan), Mr. M. B. de Groot (GeoDelft, The Netherlands), Dr. S. A. Hughes (ERDC, USA), Dr. S. Hui (Bechtel Inc., USA), Dr. D.-S. Jeng (University of Sydney, Australia), Dr. R. Kulesza (Bechtel Inc., USA), Professor A. Lamberti (University of Bologna, Italy), Dr. W. Magda (Technical University of Gdansk, Poland), Professor C. C. Mei (MIT, USA), Mr. P. Meijers (GeoDelft, The Netherlands), Professor M. Mory (University of Pau, France), Dr. T. A. Newson (University of Western Ontario, Canada), Professor A. C. Palmer (University of Cambridge, UK), Professor M. S. Rahman (North Carolina State University, USA), W. Richwien (Duisburg-Essen University, Germany), Professor T. Sakai (Kyoto University, Japan), Dr. S. Sassa (PARI, Japan), Professor H. Sekiguchi (Kyoto University, Japan), Dr. S. Takahashi (PARI, Japan), Dr. H. Tanaka (PARI, Japan), Professor F. Tatsuoka (Tokyo University of Science, Japan), Professor A. Tørum (NTNU, Norway), Dr. R. Whitehouse (HR Wallingford, UK), Professor A. L. Wing-Keung (NTU, Singapore), and Professor K. Zen (Kyushu University, Japan).

The Guest Editor owes a heart full of thanks to his colleagues in the LIMAS program for their contributions to the special issue (in alphabetical order): Dr. S. Dunn (HR Wallingford, UK), Professor P. Foray (Domaine Universitaire, Grenoble, France), Professor J. Fredsøe (Technical University of Denmark), Dr. N.-E. O. Hansen (LICengineering, Denmark), Dr. M. Kudella (Technische Universitat Braunschweig, Germany), Professor M. Mory (University of Pau, France), Professor H. Oumeraci (Technische Universitat Braunschweig, Germany), Professor A. C. Palmer (University of Cambridge, UK), Professor R. Sandven (NTNU, Norway), Professor A. Sawicki (Institute of Hydro-engineering, Poland), and a special note of thanks to Mr. M. B. de Groot (GeoDelft, the Netherlands) and Mr. J. S. Damgaard (HR Wallingford, UK, currently at WorleyParsons, UAE), the two task leaders under LIMAS, for their invaluable input throughout the entire project, particularly for their advice in organing the special issue, in selecting the peer reviewers, and participating in the peer-review process.

As previously noted, the LIMAS program has been supported by the EU, under the European Commission Research Directorate’s FP5 specific program “Energy, Environment and Sustainable Development,” Contract No. EVK3-CT-2000-00038, Liquefaction around Marine Structures (LIMAS). On this occasion, the guest editor extends his appreciation to Mr. Christos Fragakis,the scientific officer in charge of the LIMAS program, and Mr. Hartmut Barth, Mr. Fragakis’s replacement after January 2004, for their cooperation. The effort of the guest editor in preparing the special issue has been partially supported by the Danish Research Council for Technology and Production Sciences (Forskningsrådet for Teknologi og Produktion, FTP, formerly the Danish Technical Research Council, STVF) of the Danish Research Agency, Ministry of Science, Technology and Innovation Research FrameProgram Exploitation and Protection of Coastal Zones (EPCOAST) Sagsnr. 26-00-0144.

Last but not least, the guest editor thanks Ms. Jackie Perry, Managing Editor, Journals, ASCE, who has done an excellent job in organizing the publication of the special issue.