The HS2 rail network is one of the UK’s most significant infrastructure projects, designed to enhance connectivity and modernise transportation. As part of this ambitious development, the Marston Box dewatering project was a critical component in ensuring the successful construction of a pioneering rail bridge structure. Located near Junction 9 of the M42 motorway in North Warwickshire, the project required expert groundwater control solutions to enable the construction of the 190-meter-long bridge.
WJ was engaged to provide its industry-leading dewatering expertise, supporting BBV in overcoming challenging ground conditions and ensuring a stable foundation for construction.
BBV encountered significant challenges when excavating through Glaciolacustrine deposits, a mix of water-bearing sands and clays, which posed a risk to the stability of the bridge platform. To mitigate these risks, WJ was tasked with designing and installing a wellpoint dewatering system capable of lowering groundwater levels effectively and maintaining dry working conditions.
The dewatering system consisted of over 250 wellpoints, strategically installed to reach the Mercia Mudstone rock head. These wellpoints abstracted groundwater and discharged it into a purpose-built attenuation basin, allowing for controlled re-infiltration in compliance with Environment Agency (EA) licensing regulations.
What set WJ apart in this project was our ability to deliver an efficient and technically robust dewatering system under tight time constraints. With a fixed 10-day road closure window for key construction activities, precision and reliability were essential.
Key achievements of WJ’s involvement include:
This bridge project stands as the UK’s first ‘box-slide’ bridge over a motorway and the longest box-slide of its kind in the world. This engineering feat involved moving the 12,000-tonne structure into position using a ‘box jacking’ technique, requiring precise dewatering control to stabilize the foundation.
The bridge slide operation took place over a 40-hour period between December 24-26, 2022, during a full motorway closure. Remarkably, the road reinstatement was completed 36 hours ahead of schedule, underscoring the efficiency and success of the project.
At WJ, we don’t just manage water—we master it. Our expertise in dewatering and groundwater control plays a crucial role in the success of large-scale infrastructure projects worldwide. The Marston Box project exemplifies our ability to provide dependable, expert-led solutions that meet the highest standards of engineering excellence.
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!
