SPI Piling Ltd was appointed by Jacksons Civils to support a major embankment remediation scheme on the northbound M11 between Junctions 5 and 6. The location, Earthwork ID EW2319, had experienced long‑term instability including crest tension cracking, subsidence behind the vehicle restraint system, and undermining of gantry and communications infrastructure. Connect Plus Services required a durable, permanent stabilisation solution that could be delivered with minimal disruption to live motorway operations.

SPI Piling Ltd's, subcontract scope involved installing approximately 151m of permanent GU27N sheet piles, averaging 11.7m in length. Activities included offloading and storing piles in the Jackson compound, undertaking all works during restricted night‑time closures, and using silent piling methods to protect sensitive adjacent assets. SPI worked strictly to the approved Geotechnical Design Report and Works Information, with no design responsibility.

Installation was completed using a Kowan WP150 silent press-in rig to minimise vibration risk to unstable ground and motorway infrastructure. Starter piles were placed using a 35t excavator with a Movax attachment before transitioning to full silent pressing. Where difficult ground was encountered, SPI introduced controlled water jetting and pre‑augering in line with approved method statement addenda. Tight 5‑hour working windows during night possessions required precise coordination, daily mobilisation, and disciplined execution.

Safety and quality were managed through detailed RAMS, lift plans, plant inspections and workforce briefings. Working platforms were engineered to safely accommodate crane and rig loads. Silent piling significantly reduced vibration impacts, protecting gantries, drainage systems and communications assets.

Challenges included restricted possession windows, unstable ground, and close proximity to live motorway infrastructure. SPI collaborated closely with Jacksons Civils, adapting methodologies only when required to maintain programme integrity while ensuring safety and compliance.

SPI Piling Ltd, successfully installed the sheet piled retaining wall within the strict working constraints, providing long‑term structural stability to the embankment and safeguarding critical highway infrastructure. The project demonstrated SPI’s technical capability, safety‑led approach and ability to deliver reliable solutions in highly constrained motorway environments.