Context

The A21 in Kent, a busy arterial route, required upgrading to accommodate high levels of traffic.

A £70 million scheme included upgrading the carriageway between Tonbridge and Pembury to a dual carriageway and involved the construction of several new bridge structures.

The construction project required a number of reinforced soil structures to form the bridge bank seats and wing walls, a slip road retaining wall and reinforced soil slope.

Phi Group were contracted by Balfour Beatty Civil Engineering to install several substantial reinforced soil structures using the Tensar TW3 modular block reinforced soil system. Phi also designed, supplied and installed a reinforced soil slope using their Textomur system.

Work undertaken

In total, Phi Group was responsible for the installation of 6 structures in all, with a face area of over 2,500 square metres.

Fairthorne Underbridge

Installation of 733 square metres of Tensar TW3 block with the placement and compaction of over 5,500 cubic metres of fill material

Longfield Road Underbridge

Installation of 1,050 square metres of Tensar TW3 block with the placement and compaction of over 10,500 cubic metres of fill material

Tudeley Wood Retaining Wall

Installation of 230 square metres of Tensar TW3 block with the placement and compaction of over 800 cubic metres of fill material

East Road Slip

Installation of 650 square metres of Textomur reinforced soil slope with the placement and compaction of over 5,000 cubic metres of fill material

Outcome

The project was challenging, not least due to weather playing its part and causing delays. The operatives on site, led by Ricky Bishop, worked evenings and weekends where required to achieve the programme set by the contractors. 'Red Zone' working meant that a non-working Supervisor was required at all times, and only one operation, such as backfilling or delivery of blocks, was permitted in the working area at any one time. This all meant that co-ordination of deliveries etc was important to avoid any delays on site.