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Raising The Bar On Geotextile Specification

Engineer Ian FraserThe intricacies of geotextile specifications were discussed at a recent IGS UK Chapter webinar.

Speaker Ian Fraser, IGS Treasurer and Technical Director at TCS-Geotechnics, asked ‘Are you specifying and using the correct separation geotextiles?

Mr Fraser spoke about the new British Standard ‘BS8661 Geotextiles – Guidance for specification for basic separation and filtration functions’. The standard was developed with the support of the Environment Agency, Network Rail and Highways England, and replaced Clause 609, inviting a more appropriate selection of geotextiles.

Participants enjoyed a refresher on the definition of key terms and why standards are important. Mr Fraser then shared the aims and development of the new guidance, advice on using it to select and specify materials, and how to make sure products are acceptable for use under the new specification.

The talk, which attracted 55 participants, concluded:

    • Separation geotextile standards in the UK were declining
    • Minimum acceptable standards have been set to prevent this, and allow designers to make a more informed choice
    • BS8661 is for basic scenarios and not a replacement for detailed design
    • Feedback, research or data is welcome for future revisions of the standard in c. 2024. Opportunities to use different test methods may open following Brexit and any change in the UK’s relationship with Construction Products Regulations

Mr Fraser said: “A lack of knowledge about the appropriate use of the correct geotextiles can create real obstructions to achieving the economic and sustainable benefits available from these products.

“Additionally, university undergraduate courses rarely include geosynthetics or skip over them very quickly. Consequently, young engineers have little understanding of them, and their features and benefits, so naturally shy away from specifying them or are reluctant to question historic specifications.

“I hope my talk went some way to addressing that imbalance so new engineers use the standard to better understand geotextiles and design, making more informed choices about the materials they use.”

Make a note of upcoming UK Chapter webinars, including:

  • March 9, 6pm GMT –  ‘Geosynthetics in Hong Kong Landfills’, by John Cowland. This is a joint event by IGS UK and the BGA 20thInvitational Lecture.

For more on the UK Chapter, visit its website here.