A 14M HIGH reinforced soil ramp is providing vehicle access to a new distribution centre in a disused quarry at Purfleet, Essex.
Built by Keller Comtec, the ramp optimises the space for lorry movements at the Queen Elizabeth distribution park by turning 90º as it rounds a corner of the quarry.
The original plan was to build an anchored bored pile wall with a shotcrete finish at the high end of the ramp and use 70infinity reinforced soil slopes to support the remainder.
But the bored pile section would have been expensive, so reinforced soil and gravity retaining wall contractor Keller Comtec, part of the Keller Ground Engineering Group, suggested replacing it with vertical reinforced soil with precast concrete panel facings.
On the lower part of the ramp a sacrificial steel mesh facing system, Textomur, was used to prevent deformation of the steep slope face during compaction of the fill behind.
Main contractor Fitzpatrick had imported crushed concrete fines for the fill, so high density polyethylene geogrids, which can tolerate pH values over 10, were chosen as soil reinforcement.
A fine geogrid was placed immediately behind the Textomur to retain a 300mm thick band of topsoil.The finished face will be hydroseeded by Keller Comtec next month, using grass seed mixed in a mulch containing seaweed soil builder, binders and fertilisers to boost its establishment.
A friction angle of 45infinity was required for the fill behind the vertical walling on the ramp's upper section, so a higher quality well graded granular fill was used. The face was formed with 150mm thick rectangular precast concrete panels, manufactured by Bell & Webster.
Soil reinforcement was provided by up to eight 50mm by 5mm by 10.5m long galvanised steel strips bolted to the back of each panel.
The intersection of the two different types of soil reinforcement was achieved by overlapping a 5m length of the vertical concrete panels with the sloping Textomur.
Fitzpatrick began work at the end of October 2001.The project was completed two weeks ahead of the 16 week schedule.