HS2 ground investigations

The site was located within the London Borough of Camden, directly beside both sides of the Euston Station rail line approach. We were commissioned to deliver ground investigation works, including a buried utilities survey, together with geotechnical and geo-environmental information. The findings from the investigations would then enable the safe and cost-effective design for works in the Euston area.

Buried utilities survey

Fugro’s buried utilities survey work was one of the UK’s largest non-intrusive surveys to be carried out in accordance with the new PAS128 standard. The work was undertaken between April 2015 and March 2016 and included topographic, ground penetrating radar and electromagnetic locator surveys, as well as underground service tracing (e.g. radio detection) and off-site interpretation of statutory records.

Our task was to identify utilities located within the public highways and footways over an area of 260,000 m². To achieve this, we submitted numerous streetwork applications to the local authority. We also arranged work in day and night shifts, to minimise disruption.

The applications entailed very careful planning and liaison with various stakeholders – including residents, businesses and the local authority.

Intrusive ground investigations

The intrusive ground investigation phase involved cable percussive and rotary drilling to a maximum depth of 60 metres. Other works, most of which we carried out using Fugro’s in-house resources, included:

• Windowless sampling

• Cone penetration testing

• Hand-excavated observation pits

• Dynamic probing

• Shallow road cores

• Pressuremeter testing

• Down-hole geophysical logging (including parallel seismic logging)

Some of the boreholes were positioned very close to the existing railway walls leading up to Euston Railway Station, so we had to carry out 3D deformation monitoring of these structures during the drilling works.

Exploratory locations were mainly positioned on very busy public highways or pavements, which constrained the working areas. Prior to designing the traffic management plans, we liaised with local authorities to obtain the required necessary permissions.

HS2 Ltd is committed to being a good neighbour to any communities it affects. Fugro fully supported this approach and obtained all relevant noise and environmental health consents. We used a range of acoustic barrier systems to minimise noise disruption and all traffic management systems were designed to minimise disruption to road/pedestrian traffic.

Results

We delivered the results from the buried utilities survey to the client in the form of a fully interactive 3D model, accompanied by a PAS128-compliant survey report. The findings allowed HS2 to design and implement the utility diversion works that are required in and around the Euston Rail Station area as part of the main works.

The findings of our intrusive ground investigation provided vital geotechnical and geoenvironmental information, enabling the client to design and construct the proposed main works around Euston Railway Station, safely and cost-effectively.