The Northolt Tunnel West is a crucial segment of the HS2 high-speed railway project, stretching 5 miles (8 km) from the West Ruislip Portal to the Green Park Way Ventilation Shaft in Greenford. Following the Chiltern Main Line, this section includes a series of cross passage tunnels positioned every 500m between the two running tunnels, primarily for safety and emergency evacuation. The tunnel boring machines (TBMs), Sushila and Caroline, were launched in late 2022 to construct the running tunnels, requiring a carefully managed groundwater control system to facilitate excavation of the cross passages.
WJ was engaged to design, install, and operate a groundwater control system to enable safe excavation and sprayed concrete lining (SCL) installation for the cross passages.
The excavation of the seven cross-passage tunnels required:
WJ’s expertise was integral in delivering:
WJ’s groundwater control systems played a crucial role in ensuring safe and efficient cross passage excavation. By combining innovative modelling, specialised drilling solutions, and real-time monitoring, we helped keep the project on track while mitigating safety risks.
At WJ, we provide more than just dewatering—we engineer solutions that enhance efficiency, safety, and sustainability. Our involvement in the HS2 Northolt Tunnel West project demonstrates our ability to apply cutting-edge techniques and industry expertise to some of the UK’s most complex infrastructure challenges.
WJ Group have completed many projects in the UK and globally. Click on the links below to learn more about what we do.
Are you ready to see what else our vision can bring to your projects? Speak to our team of groundwater experts today!
