Notable projects

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The range of projects and environments where the pressuremeter test can be used is extensive. It is widely used off-shore as well as on land, in deserts, in mountains and in tropical conditions.

Every project has its own set of problems and difficulties that have to be overcome. This might mean man-handling equipment in remote locations, such as Tanzania or The Gambia, or using helicopters to deposit equipment on a rock glacier in Switzerland. It is not usual for us to run a completely self-contained operation. Most of the time we have to work with a local drilling contractor and operatives who will be unacquainted with our equipment and unused to what is required for a successful pressuremeter test. This is not a major difficulty, and our engineers are accustomed to looking after the on-site training involved.

Our pressuremeters have been used on some of the world’s major civil engineering projects, such as Crossrail in London or the proposed crossing of the Padma river in Bangladesh. What follows is a selection of some of the more unusual projects.
 

The underground research facility at Mol, Belgium

Horizontal self boring in Boom Clay using air from a modified drill rigWe have at intervals over the last 15 years made visits to the SCK-CEN facility at Mol, Belgium, to carry out pressuremeter testing in the underground research facility HADES. This is a system of shafts and tunnels some 224 metres below ground level in a zone of Boom Clay in a highly plastic condition. The clay has interesting self healing properties when fractured, displays extremely low levels of permeability and offers a possible solution to the problem of the disposal of high level nuclear waste. Since 2000 the facility has been run by an expert group called EURIDICE and pressuremeter testing has been used during the construction of the facility and after to examine the engineering properties of the clay.

Testing waste and investigating barrier walls

A view across a municipal waste site where pressuremeter testing was carried outWe were approached by Dr Neil Dixon of Loughborough University (now Professor of Engineering) about the possibility of using a pressuremeter to investigate the mechanical properties of municipal solid waste. Most of the work took place at a landfill site in Calvert, Buckinghamshire. The waste was a mixture of residential and commercial residue, not well-sorted, in various stages of degradation and depending on its age could be lightly to heavily compacted.

The primary purpose of the testing was to obtain engineering parameters that would permit the interaction between the body of the waste and the components of the protective barriers to be modelled and quantified.

Kolkata Metro East - West Project

Twenty four self bored tests were carried out at four critical locations along the alignment of the proposed metro in Kolkata, India. The pressuremeter testing component of the site investigation had been specified by W S Atkins. For the most part the tests were conventional in material that behaved either as a clay or sand. What was different about this project was the technical and practical difficulties that had to be overcome to achieve success - see figure 1.

figure 1 self boring rig in Kolkata
Fig.1 Self boring in Kolkata (click for full-size)