The project consisted of the rehabilitation and extension of the existing operational runway, aprons and taxiways, to take larger modern aircraft. The work was carried out in conjunction with Geomarine, a Guernsey based civil engineering contractor to the specifications of RPS, specialists in airport infrastructure, design construction and airfield technology.
RSA Geotechnics carried out a site investigation of the airport and its surroundings as part of the improvements to the existing runway. The desk study provided historical and land use data and the intrusive investigation providing information on the underlying soil and ground conditions.
The intrusive phase of the investigation consisted of twenty seven trial pits with ten in-situ plate bearing tests and nineteen windowless sample boreholes with the installation of nine long term groundwater monitoring wells. The construction of the existing runway, taxiways and aircraft parking aprons was also investigated by eighteen diamond drill cores.
As the airport was operational much emphasis was placed on safety. The ground investigation required the production of detailed risk assessments and method statements. Most of the fieldwork was carried out at night and close liaison was required with the airport authorities.
The interpretative section of the investigation included a desk study, a qualitative risk assessment of contamination and geotechnical advice regarding earthworks, pavement design and foundation design. Geotechnical advice was provided in relation with the anticipated cut (2 to 3m) and fill (up to 10m) operations. Advice covered the fact that some of the soils on site were expected to be particularly susceptible to water softening. Guidance was provided for the reuse of site-won soils based on in-house laboratory testing. CBR values for various soil types were measured and evaluated. Settlement assessment of areas of fill were made and advice given on how to control it.
On completion of the fieldwork George Stevenson, the airport operations manager, had this to say:
“We received full cooperation from the RSA team, who worked extremely hard and demonstrated exemplary airside safety awareness throughout the whole project.”