ASCE GSP 235-2014 Geo-Congress 2014.pdf

1、GEOTECHNICAL SPECIAL PUBLICATION NO. 235 GEO-CONGRESS 2014 KEYNOTE LECTURES GEO-CHARACTERIZATION AND MODELING FOR SUSTAINABILITY PROCEEDINGS OF THE 2014 CONGRESS February 23-26, 2014 Atlanta, Georgia SPONSORED BY The Geo-Institute of the American Society of Civil Engineers EDITED BY Anand J. Puppala

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9、es of America. Preface The 2014 Geo-Congress conference, titled “Geo-Characterization and Modeling for Sustainability,” was held February 23-26, 2014, in Atlanta, Georgia. The proceedings of the 2014 Geo-Congress are included in two Geotechnical Special Publications, GSP 234, Geo-Congress 2014 Techn

10、ical Papers, and GSP 235, Geo-Congress 2014 Keynote Lectures. The 2014 Geo-Congress conference was organized by the Geo-Institutes technical committee on Engineering Geology and Site Characterization (EG mark.cassidyuwa.edu.au 2Associate Professor, Centre for Offshore Foundation Systems and ARC CoE

11、for Geotechnical Science and Engineering, Uni. of Western Australia, Perth, Australia; conleth.oloughlinuwa.edu.au 3Professor, Centre for Offshore Foundation Systems and ARC CoE for Geotechnical Science and Engineering, Uni. of Western Australia, Perth, Australia; christophe.gaudinuwa.edu.au 4Assist

12、ant Professor, Civil & Environmental Engineering, University of Maine, Orono, Maine, USA, melissa.L.maynardmaine.edu ABSTRACT: The worlds escalating demand for energy, combined with the depletion of oil reserves in shallow waters and traditional regions, is resulting in the move of offshore developm

13、ents into deeper waters, new development regions and transformation to cleaner natural gas and renewable energy sources. Summarized in this paper are the geotechnical challenges facing the offshore industry as it attempts to sustain the worlds expanding energy demands. Representative examples of new

14、 methodologies being used in engineering design are provided, including deep water anchoring and mudmat systems, installation of mobile jack-up platforms in the stratified soils that are often encountered in new development regions around Australasia, and the potential use of caissons for floating w

15、ind farms. INTRODUCTION In an era of escalating energy demand, securing long-term resources is one of the major challenges of our generation. Together with a need to mitigate increasing CO 2emissions and climate change, engineers are faced with the additional challenge of conversion to low-emission

16、energy sources. The worlds oceans hold significant potential for solutions. However, discovery of these reserves of cleaner natural gas and offshore renewables requires new approaches. Geotechnical engineering has significantly contributed to the development of offshore energy reserves in the past.

17、However, significant challenges remain, with safe and efficient technologies required to unlock future energy resources in our extensive marine environment. This paper provides an analysis of current energy trends and the potential role of geotechnical engineering in providing novel solutions in the

18、 offshore environment. The paper also discusses examples of applications in which practical analytical and calculation methods have been developed to move offshore energy recovery into deep waters, new regions, and for technology transfer to cleaner sources. The focus of the paper, rather than a com

19、prehensive review of all areas, is on critical examples of possible solutions and challenges to offshore geotechnics applications. 1 Geo-Congress 2014 Keynote Lectures, GSP 235 ASCE 2014Page 2 AN ERA OF ESCALATING ENERGY DEMAND The worlds demand for energy continues to increase unabated, with the to

20、tal supply doubling from 5 600 MTOE in 1971 to over 12 700 MTOE in 2010 (Figure 1, after IEA, 2012 a ). This energy demand is causing an infrastructure and resource boom in many developing offshore regions. For instance, US$120 billion worth of infrastructure projects are currently under constructio

21、n off the coast of Australia (RBA 2011). Although low-emission renewable energy is highly desirable, it still only accounts for a little over 3% of the world energy supply, with the majority of that being a 2.3% contribution from hydroelectricity (2010 IEA data, 2012 a ). Figure 1. Total primary ene

22、rgy supply (from IEA, 2012 a ) Governments worldwide are instituting carbon emission reduction strategies, and several have set targets for a mix of renewably generated electricity. For instance, the UK and China have set targets of 15% renewably generated electricity by 2015, whereas Australia and

23、Europe (averaged across the union) have a target of 20% by 2020. Thirty states of the USA have ambitious targets, such as 30% by 2015 (New York), 30 and 33% by 2020 (Colorado and California) and 40% by 2030 (Hawaii). Building offshore developments in deep water, remote locations, and for renewables

24、necessitates paradigm shifts in geotechnical design. The characteristics of these frontiers and the geotechnical challenges and examples of solutions are summarized in Table 1. These challenges are expanded in the following sections, with examples of solutions and challenges for each provided. ULTRA

25、-DEEP WATER Challenges off the continental shelf The depletion of known hydrocarbon reserves in traditional regions and in shallow waters is resulting in the movement of exploration and development to deeper waters and often into untested environments. Internationally, in the Gulf of Mexico, West Af

26、rica and offshore Brazil, developments have proceeded off the continental slope into water depths approaching 3000 m, with prospects beyond 4000 m currently considered by Total in West Africa. These deep water environments are typically characterized by soft, lightly overconsolidated, fine-grained s

27、ediments. 0 2000 4000 6000 8000 10000 12000 14000 1970 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003 2006 2009 2012 Energy Supply (Mtoe) Ye a r Proportions in 2010 Oil 32.4% Coal/Peat 27.3% Natural gas 21.4% Biofuel/waste 10.0% Nuclear 5.7% Hydro 2.3% Geothermal/solar/wind 0.9% 2 Geo-Congress 2014 Keynote Lectures, GSP 235 ASCE 2014