The past year has been very busy for White Young Green's (WYG) site investigation team. Director Adam Marshall hopes that trend will continue.
But the introduction of Eurocode 7 which standardises soil and rock classification and description is something to watch out for, he adds.
"This will hopefully lead to improved technical quality, which is lacking in some site investigations (SIs). The increasing requirement for warranties on site investigation should lead to more comprehensive scopes and hopefully will lead to increased spend on investigation work.
"We may also start to see an increase in the demand for multi-discipline site appraisal, with combined geotechnical and contaminated land assessment becoming the norm," he adds.
This is certainly the case on a recent project, which saw WYG's SI team using both intrusive and non-intrusive techniques at 34 sites for Leeds Independent Living. At each location the company carried out a multidisciplinary site appraisal to give the client a comprehensive set of ecological, archaeological, environmental, contamination and geotechnical data, as well as carrying out utilities mapping and acoustic surveying.
The company has also carried out its largest SI contract to date this year, for a new development in Stratford, East London. Here, the SI team has undertaken 450 boreholes, 300 window sample boreholes, 230 trial pits and 40 cone penetration tests (CPTs) and taken more than 25,000 samples for laboratory testing.
One of the biggest challenges has been access to the isolated site, which the team overcame with a range of access techniques, including using a hovercraft for river sediment sampling.
Other recent work includes investigating the former Scout Road landfill site in West Yorkshire for Calderdale Metropolitan Borough Council. WYG's contract involves providing the client with sufficient information to determine the stability of the site – an active landslip area – and to provide interpretative reports on the geotechnical aspects and determination of pollutant linkages that may exist for known pollutants.
The site in the Calder Valley, slopes steeply and is wet and heavily wooded, conventional ground investigation techniques difficult. The presence of asbestos waste also limited the investigative options.
WYG has carried out non-intrusive investigation in the form of topographic survey and geomorphological mapping to help create a slope model. It used a specialist slope climbing drilling rig for rotary drilling boreholes in mid-slope areas, targeting critical areas of the slope to augment the non-intrusive work.
The intrusive phase of the investigation is now substantially complete, and instruments have been installed in critical areas on the slope to help the SI team reach a detailed interpretation of the conditions. A further 48 weeks of monitoring will be used to determine the pollutant linkages.