An embankment 25m high by 300m wide and 800m long had to be constructed to support
the second runway at Manchester’s International Airport.
The material available to construct this embankment consisted of a high clay content and having a permeability, in the order of, 1 x 10-7 m.s-1. The material was also wet which would cause slow consolidation rates. It was therefore necessary to find a method of speeding up the consolidation rate to meet the construction deadline.
The solution was to install Terram 1B1 (geocomposite drain) at 2m horizontal centres and at 2m staggered vertical lifts. A roll size of 2m x 100m was supplied to facilitate the speed of installation.
The contractor and project design engineers were pleased with the performance of Terram 1B1 and the speed at which the calculated settlements were achieved.