Frogmore Connection Tunnel

Whilst WJ are well known and respected as one of the leading dewatering contractors in the UK, we have many other services within our oeuvre. A fine example of this was when we undertook in-tunnel probe drilling as part of the Thames Tideway West works in Wandsworth.

As part of the multi-billion pound Thames Tideway ‘super-sewer’ scheme underneath London it is necessary for a connection tunnel to be constructed, dubbed the ‘Frogmore Connection Tunnel’, connecting King George’s Park in Wandsworth to the Carnwath Road site on the north of the River Thames in Fulham.

WJ In-tunnel Drilling

WJ In-tunnel probing on Thames Tideway

WJ have been undertaking pumping tests and dewatering on a number of Thames Tideway sites since early on in the project, however as part of the construction of the Frogmore Connection we had the opportunity to showcase one of other services at the Dormay Street Shaft site.

Prior to each advancement of the connection tunnel it was necessary for investigative probing to take place to confirm ground conditions ahead of the advancement. To do this, WJ’s SM5 drilling was lowered in to the shaft, and a range of probe holes were drilled at a range of inclinations from horizontal to 12⁰ from the horizontal and 12⁰ to the left and right, collecting geological samples with each probe. After each round of probing the tunnel was advanced, before another round of probe holes were drilled.

Whilst inclined in-tunnel drilling and probing is not uncommon in the UK, WJ are one of the best equipped companies to undertake such works, due to our extensive experience of in-tunnel work from the Thames Tideway, Crossrail and Northern Line Extension works, amongst other projects, our highly experienced drilling and supervisory staff, and our fleet of drilling rigs capable of drilling in restricted tunnel environs at a range of inclinations of directions.



  • LOCATION: London


  • In tunnel probing

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