UP CLOSE: Dr. Toby Roberts, Chairman, WJ Groundwater Ltd

Dewatering strategies for tunnels, shafts and excavations deployed during London’s Crossrail UK mega projects will be the focus for Dr. Toby Roberts’ presentation, when he joins a number of international experts addressing Informa’s 14th Australian Tunnelling Conference, taking place in Sydney on 11-12 October.


Dr. Toby Roberts, Chairman, WJ Groundwater Ltd

Dr. Roberts will share his expertise on overcoming restricted access, in-tunnel wellpoint techniques, risks and mitigation measures, plus the lessons learnt from this important international project.

Failure to adequately control groundwater during tunnel construction can result in delays, cost overruns and occasionally catastrophic failure. Groundwater control is not generally required for TBM drives but dewatering may be needed for shafts, cross passages, launch and reception pits and for open face or sprayed concrete headings. Dewatering from the surface is often preferred but is not always an option in congested urban areas. Use of inclined wells can sometimes be used to overcome access restrictions. Where inflow rates are modest in-tunnel dewatering schemes can be a viable alternative to ground freezing or grouting. In-tunnel dewatering strategies were developed to a high degree of sophistication for cross passages and SCL station works for the recent Crossrail project in London, UK. For larger open cut excavations external well systems may be preferred but careful consideration needs to be given to the potential for offsite impacts.


Dr. Toby Roberts is an expert on the design and implementation of groundwater control systems for large excavations, foundations and tunnels with extensive contract experience in the Middle East and Europe. A founder member and current Chairman of the international dewatering contractor WJ Groundwater. He co-authored the recent UK practice guide CIRIA report C750, Groundwater Control: Design and Practice (pub 2016). Dr. Toby Roberts has published widely in journals and at international conferences on dewatering techniques and is a Fellow of the Royal Academy of Engineers, a Charted Civil Engineer and Chartered Geologist.

If you’d like to hear more from Toby during his visit to Australia, view the full conference agenda for the 14th Australian Tunnelling Conference and book your spot for this October.


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