Stabilising the cliffs at Scarborough Spa, UK
After the discovery of spa waters in the 17th century, the seaside town of Scarborough, UK, amassed great popularity; architects and developers helped to make it into the largest holiday resort on the Yorkshire coast. By the 1880s, the waters’ chemical composition had altered, so the spa’s popularity gradually waned. Now, the venue is more famous as a music venue. Today, in 2020, the building is owned by Scarborough Borough Council and managed by Sheffield International Venues. The building’s location in front of South Cliff means it requires protecting from rockfalls.
A £13-million South Cliff slope stabilisation scheme began in May 2018 on the cliffs behind the spa complex. Balfour Beatty hired CAN, an RSK company, for its renowned difficult-access expertise to help with the work above the historic building. Working on-site on the Yorkshire coast through two consecutive winters, we installed soil nails, horizontal drains and a slope-facing system. As it overlooks South Bay, the site was particularly challenging to access. Because of the publicly sensitive nature of the spa, the stabilisation work had to be delicately handled and obscured from view on completion.
Precision planning and neat completion
After analysing the project, CAN engineers formulated a plan to install the designed solution of erosion matting and tensile steel mesh over the slope to ensure stability. CAN technicians installed 4500 soil nails ranging from 4 to 20 m in length, which required almost 70 km of drilling using CAN designed and built slope-mounted drilling rigs. On-site, we used half a million litres of grout to bond the soil nails and drilled more than 3 km into the slope to install the drains. To complete the stabilisation work, we laid geocells and 2600 t of topsoil over the entire slope and spread hydroseed to promote revegetation and restore the slope to its original semi-wild state.
CAN completed its programme of work in the agreed programme, and budget, to the highest praise from the client. CAN’s work was shortlisted for a Ground Engineering award. Within a few months, the substantial stabilisation work was unidentifiable.