Blackfriars Station, London

As part of the £6bn Thameslink upgrade, Blackfriars Station was completely rebuilt and now extends across the Blackfriars Bridge. Part of the work involved demolition of platforms and roof of the over-ground station and the main contractor had to ensure that trains could continue to run through the station before the demolition and re-construction works could proceed. The solution to this was a massive steel cover for the tube lines known as a Track Protection Structure (TPS) – essentially a series of steel arches connected to a steel base which was secured to the underground platform.

Diamond Edge Drilling Ltd, in partnership with JJM Rail Ltd, were contracted to carry out the strengthening and foundation works to the underground platform to allow construction of the TPS. Our services were required to form twenty-two capping beam foundations in the platforms to support the TPS.

Two hundred and fifty 107mm holes were diamond drilled 3 metres deep into the platform footings, reinforcing bars inserted and the holes filled with a specialist grout to form mini strengthening piles through the platform. To form the capping beams to which the TPS would be attached, twenty-two openings were floor sawn and broken out around the piles. The piles were then cropped to the specified level with handheld hydraulic crunchers, reinforcement placed in the openings to engineer’s spec and concrete poured.

As with a lot of work on the underground and railway network, strict timescales had to be adhered to. Blackfriars Underground Station was closed to the public during weekends to facilitate these works. Our work was completed in just two 48-hour possessions of the station, resourced with six diamond drilling, floor saws, hydraulic crunchers and three teams of seven operatives working in shift rotation throughout both weekends. The drilling rigs were mounted on custom-made track systems to increase productivity and guarantee precision as very tight tolerances were required.