23 February 2010
A state-of-the-art drilling rig is being used to assess the condition of the earth structure along the London Underground (LU) network.
The ‘cut-down Premier 100 rig’, supplied by Dynamic Sampling, has been approved and rigorously tested to the high standard of all equipment on the LU network. It has the capability of super heavy dynamic probing, standard penetration testing and undisturbed sampling and is ideal for geotechnical and geo-environmental rail related projects such as platform extensions, Disability Discrimination Act(DDA) station schemes and slope stability projects.
Stuart Phillips from WYG is framework manager for the project. He said: “the approval of the Premier rig increases our options to achieve a better quality ground investigation than has previously been possible. Before the rig became available, we were limited to using hand held window sampling equipment in most places, but the Premier rig gives us the potential to achieve greater depth, to deal with more difficult ground conditions, and potentially to achieve better sample quality than was previously possible”.
“The main benefits of the rig are that it is fully demountable and breaks down into around 25 component parts. The heaviest part is the percussive weight which weighs around 63.5kg. The rig can then be transported by hand or track trolley to a variety of restricted access locations,” he added.
WYG has been quietly working away as Principal Contractor on the LU Earth Structures Ground Investigation Framework for over five years. The framework was set-up in 2004 and charged with carrying out ground investigation for assessment of earth structures on the LU Network.
Over 70 ground investigations have been carried out for LU on a variety of sites across the network. Works have been carried out during traffic hours, engineering hours, possessions and closures. They have comprised various activities but generally restricted to window and windowless samples and hand pitting due to access constraints. For the majority of sites, there is no access for vehicles, so the equipment has to be carried in by hand. Where access is possible, standard or modular cable percussion rigs have been used.
WYG has their own designated LU team based in London, which includes approved contractors agents, logging engineers and site persons in charge. The company offers a complete package to clients, including planning, ground investigation, environmental and geotechnical consultancy services.