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Don Valley Viaduct Bridge Strengthening

Van Elle undertakes rail ground investigation (GI) at Paris depot with hundreds of unexploded world war bombs potentially buried deep in the ground.


Working closely with STRATA Geotechnics, Van Elle’s ground investigation subsidiary, the Rail Division mobilised an experienced team to work on the very precarious ground investigation project to the North West of Paris. The project was to provide samples and data regarding the ground conditions in preparation for the new development of a rail maintenance and testing building for the SNCF.

The project started with mobilising our unique and specifically engineered road rail GI drilling unit the VE-MOG. Having won various accolades within the ground engineering fraternity, the VE-MOG has the capability to undertake rotary percussive drilling on and off track, with its easy access capability it can manoeuvre between road and rail track within minutes.


Our team used our in-house transport fleet to ensure the VE-MOG travelled to France in safety and in accordance with both British and French road laws, arriving in Syndicat CGT, Acheres, France, which is in the North West of Paris and on the banks of the River Seine. (approx. 24km from the centre of Paris),

The depot is a key access point and crucial maintenance and storage facility for the Paris Metro. Having the ability to build a brand-new facility, the SNCF will gain over 1,800 SQM of maintenance and testing space to undertake vital work.

Once arrived, after battling Storm Dennis on a treacherous Ferry crossing, our engineers got to work unloading the vehicles and drilling equipment in preparation to commence 7-days worth of ground investigation works. Our client for this project was 1st Horizon who are a global survey, mapping and measurement company who have a real pedigree in the rail sector.

Their client is RS Components who are a global trading brand of Electrocomponents plc, supplying electronic components, electrical automation and test and measuring equipment. Founded in 1937 they serve UK, Europe, Asia and the Americas.

The scope of the project was to carry out GI sampling, testing and remediation works. Before this however, we had to undertake a full utilities sweep, trial holing and UXO probing (unexploded ordnance) to uncover more details regarding any unexploded bombs. It is reported 336 No. bombs fell during the German bombings of the critical infrastructure site in WWII. This work was also carried out during our drilling programme to support our approach to health and safety and risk management.

Utilising the VE-MOG we drilled 4 No x 15m rotary percussive boreholes all with the vehicle in on-track mode, working from the rails to undertake the work. In addition, we also carried out 8 No x 3m window samples in off-track mode, providing the samples and standard penetration tests (SPTs).


Our experienced team, working closely with the client, managed to complete the programme ahead of schedule which has reaped real benefits in accelerating the design process for the foundations works.

John Allsop, Rail Engineering Director for Van Elle stated,

”We have a unique piece of kit in our fleet that is capable of performing intricate ground investigation work both in the rail and highways environments. Our experience in mobilising to site effectively and then working efficiently, even under precarious conditions, with rigour and safety at its paramount this project has been a delight to work on. This powerful road rail vehicle has enabled us to deliver on demand from across our waters and we look forward to exploring more opportunities in France and across Europe.”