HS2 – Eiffage Kier works, ground investigations

Eiffage Kier’s works in the Wendover area have been focused on understanding the ground underneath where the track will be built. This is called ‘Ground Investigation’ or ‘GI’.

GI is particularly important in high speed rail, as modern high speed trains travel at around four times the speed of Victorian trains. When the original railway network was built in the 19th century, the track and trains could follow the landscape’s natural curves. High speed trains need a flatter track, passing over and under the natural landscape; so understanding the ground conditions is vital to building a safe railway. HS2 has completed the largest GI programme in the UK, with 8,000 boreholes dug across Phase One, and over 1 million lab tests carried out.

In the Wendover area, we have completed seven boreholes between 40 and 50 metres deep. In the coming weeks we will continue with our current GI programme, which will include a ‘packer test’: Two inflatable rubber balloons will be dropped in one of the boreholes we have already drilled in the field next to the Grove Farm Compound. Low pressure water is then pumped in, and the flow measured. The results tell us the permeability of the different ground strata. The test uses small equipment and will be completed in one to two days.

Fusion JV’s planned archaeological investigations in the Wendover area have been completed on site, and are now being evaluated. The outcome of this evaluation will determine if any further investigations are needed.

HS2 website for information: hs2inbucksandoxfordshire.commonplace.is/