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Glass-Fiber Reinforced Polymer (GFRP) Rock-bolts used as temporary & permanent reinforcement in single-shell mined tunnels & caverns

by Pierre Hofmann – Dextra Group


24 February 2022


10:30 am



Mined caverns are becoming increasingly popular underground structures, and particularly in Hong Kong. They offer a unique solution to space constraints, especially in dense urban environments. In large excavations, and when permitted by the rock mass, permanent rock-bolts combined with sprayed concrete are logical alternatives to concrete lining. On the heels of the successful trial of the Jurong Rock Caverns in Singapore (2012-2014), several caverns are now being constructed using GFRP rock-bolts as rock-reinforcement. The performance characteristics of these rock-bolts, namely regarding tensile & shear resistance, durability in saline and alkali environments and environmental impact, have since been published in a number of studies. In this seminar, we will discuss the characteristics of GFRP rock-bolts, the advantages & disadvantages compared to conventional techniques and the applications supplied by Dextra on three existing projects.

About the Speaker:

Pierre graduated with a Master of Engineering from “Ecole Centrale de Lille” and a Master of Science in Project Management from “SKEMA Lille”. He joined Dextra in 2007 to develop ‘Fiber Reinforced Polymers’ (FRP) soft-eye technology used in metro systems. He led the development of FRP anchors used first on Doha metro (Qatar) and then internationally. Lately, he has been promoting FRP as a permanent reinforcement and a substitution to steel, which was adopted in 2018 on the world largest underground oil-storage cavern. After 15 years at Dextra, Pierre is General Manager - Geotechnical Product-Line.

Registration : 

Please register by 21 th February 2022. Successful applicants will receive webinar details on 22 th February 2022. CPD certificate will be sent to the attendees after the webinar.

Book Prize :

Book prize is open to youth professionals under 35 years old for the submission of a quality report (max. 500 words) on this event. Please refer to the AGS HK website for “The AGS Book Prize Reports – Assessment Framework” for details. The Book Prize reward comprises a book "Geology of Site Investigation Boreholes in Hong Kong" by Chris Fletcher and book coupons worth HK$300 from Eslite Bookstore ( 誠品書店 ). Please send your report to

Keywords: Tunnel,Cavern

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Reference materials

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