EU LIMAS Liquefaction around marine structures

1. EU LIMASLiquefaction around marine structures Workpackage 7, NTNU Trondheim Development of soil sampler for measurement of gas content in soils Scope of work By associate professors Rolf Sandven (NTNU) and Mike Long (UCD)

2. Liquefaction around marine structures ISVA, DTU (DK) UPPA, Pau (F) LWI, TU Braunschweig, (D) INPG, Grenoble (F) LIC engineering (DK) NTNU, IfG (N) GeoDelft (NL) Project period 2001 - 2004 HR Wallingford Ltd. (UK) UCAM-DENG (UK) EU LIMAS - NTNUProject participants

3. Overall objectives for further work with the new sampler for gassy soils Realistic ambitions limited time limited funding Scope of LIMAS bring new interest into sampling of gassy soils contribute to further development of techniques Development in steps start with simple, but useful sampling and measuring method gradual elimination of limitations as refinement is added to the equipment EU LIMASLiquefaction around marine structures

4. Problem maintain natural level of saturation and gas content of soil sample during and after sampling verify the gas content in obtained samples through direct or indirect measurements minimise mechanical disturbance of soil sample during the sampling process Scope of work develop soil sampler with pressurised sample cylinder evaluate methods for detection of gas content in obtained samples documentation of performance and working principles through laboratory and field studies EU LIMASLiquefaction around marine structures

5. Criteria for new soil sampler should be able to cope with many types of sediments simple system for control of pressure in sample cylinder should primarily be applicable for depth range between 0 - 5 m under the seabed level minimal soil disturbance and compaction by intrusion of the sampler body Criteria for new soil sampler the sampling equipment should be portable and possible to operate by different drilling units limited maintenance required after sampling operations are completed re-use of sealing device in subsequent sampling EU LIMASLiquefaction around marine structures

6. Plan of activities start May 2001 duration 6 personmonths Phase 1 literature survey with review of possible working principles for new sampler literature review and evaluations of possible sealing techniques literature review of various techniques for detection of gas bubbles and measurement of gas volume in soil samples EU LIMASLiquefaction around marine structures

7. Plan of activities start December 2001 duration 12 personmonths Phase 2 based on evaluations and findings made in Phase 1 presentation of ideas and suggestions to project partners laboratory study of possible sample sealing techniques step-wise development of new sampler for investigation of soil composition and real gas content testing of prototype in controlled laboratory test conditions EU LIMASLiquefaction around marine structures

8. Plan of activities start January 2003 duration 14 personmonths Phase 3 modification of prototype after laboratory tests in situ test program on suitable sites (partner project sites) final modification of prototype with technical documentation, patenting and reporting from field and laboratory test studies EU LIMASLiquefaction around marine structures