Engineers should use updated specification for ground investigation in Ireland
01 June 2017
The Geotechnical Society of Ireland (GSI) and Engineers Ireland published the second edition of the Specification of Ground Investigation in Ireland in 2016. This is a revised version of the 2006 first edition, which has been fully updated in order to incorporate changes in practice due to Eurocode 7, environmental legislation and practice and health and safety legislation.
It is intended that the document will be used by all engineers and client representatives in the scoping, planning and implementation of ground investigations for building and infrastructure projects in Ireland. The emphasis of the document is on encouraging carefully designed and safely executed, good quality geotechnical work.
The document contains a technical specification, notes for guidance and bill of quantities. The notes for guidance are provided for each stage of a site investigation, including desk studies, site reconnaissance and intrusive investigations. A summary of the some key additions and changes in the second edition are given below.
Sample of changes/updates from the first edition
- For improved ease of use, the ‘Notes for Guidance’ are now included beside the main text rather than in a separate document;
- The specification has been brought up to date to reference the relevant European Standards (EN), (which have been implemented as the Irish National Standard since the first edition was published), ISO standards, quality management systems, hazardous ground and safety legislation.
- The requirements of the Project supervisor design process (PSDP) in the site investigation procurement process are identified;
- There is significantly more detail and guidance in all sections;
- A new role, termed the ‘investigation supervisor’ is introduced. These are named individuals appointed by the employer to ensure that the technical objectives and quality of the investigation are met.
- The requirements of the PSDP in the site-investigation procurement process are identified.
Section 4 – Percussion boring
- New details for backfilling boreholes, dealing with artesian water conditions, window/windowless sampling;
- Direction is provided for protection of aquifers to prevent upward/downward migration groundwater;
- New details included for backfilling boreholes, artesian water and for window/windowless sampling.
Section 5 – Rotary drilling
- Geobor coring and resonance (sonic) drilling are included. The experience of obtaining high quality (Class 1) samples using Geobor coring techniques in cohesive glacial till is noted in the guidance notes.
Section 6 – Sampling and monitoring during intrusive investigation
- This has been updated for the requirements of the relevant ISO standards for obtaining Class 1 samples.
Section 8 – Probing and cone penetration testing
- This is a new section.
Section 9 – Geophysical surveys
- This section is fully updated with more detail and guidance on geophysical techniques and reporting.
Section 11 – Instrumentation
- Now includes inclinometers, slip indicators and extensometers.
Section 14 – Geotechnical laboratory testing
- Section 14.6 provides new information and guidance for assessing pyrite in natural soils and granular fill (hardcore) under floor slabs. This is particularly relevant where investigations are conducted on exising buildings to assess the potential risk of pyrite induced expansion.
Section 15 – Geoenvironmental laboratory testing
- This is a new section.
Section 16 – Reporting
- Section 16.9 sets out what an interpretative report should evaluate.
- There is an extensive list of references which provides the user with guidance on where further information can be obtained.
Bill of quantities
- This provides an extensive ‘shopping list’ and is structured with a wide selection of current and best practice investigation techniques that should be employed.
- This is available, on purchase of the Specification, in in electronic (Excel) format
Benefits for widespread adoption of the new GI Specification
The main benefits from widespread adoption of the Specification across the industry will be to:
- Raise overall standards in the industry with fewer poorly specified investigations;
- Fairer tendering for contractors, as minimum standards will be better recognised and implemented;
- More consistent standard of specification.
We recommend its use as a ‘base specification’ with add-ons, specialist or tailored items in a cover particular specification. The specification should cover >95% of the requirements of most investigations.
It is the Geotechnical Society of Ireland’s opinion that successful ground investigation work will only be accomplished when the quality and appropriateness of the work, rather than the lowest cost, are prioritised. Attention must therefore be given to initial desk studies, careful planning, the employment of properly equipped contractors, utilising competent operatives and the supervision of the field and laboratory work by experienced geotechnical engineers.
The involvement of an appropriately qualified and experienced chartered engineer or professional geologist is also considered to be essential in the planning, procurement, supervision and reporting of ground investigation works.
The Specification is available for purchase from Engineers Ireland’s online shop at a price of €50 and includes the option to receive an electronic version of the Bill of Quantities in Microsoft Excel format.http://www.engineersjournal.ie/2017/06/01/engineers-should-access-updated-specification-for-ground-investigation-in-ireland/http://www.engineersjournal.ie/wp-content/uploads/2017/06/ground-investigation-ireland-1024x580.jpghttp://www.engineersjournal.ie/wp-content/uploads/2017/06/ground-investigation-ireland-300x300.jpgCivilEngineers Ireland