HS2 N1-N2 Bromford Tunnel East Portal & Water Orton Cutting Dewatering

Project overview

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 major development, the Bromford Tunnel East Portal (BTEP) and Water Orton Cutting (WOC) required expert groundwater control solutions to enable the successful construction of the tunnel’s eastern portal and associated infrastructure. Located off Attleboro Lane in Water Orton, the portal serves as the launch site for tunnel boring machines (TBMs) Mary Ann and Elizabeth, tasked with excavating the 5.6 km twin-bore Bromford Tunnel.

Client

Balfour Beatty VINCI (BBV)

Project owner

HS2 Ltd

WJ was engaged to provide dewatering expertise, ensuring stable excavation conditions for the tunnel portal and supporting structures.

Project Scope and Challenges

The eastern portal is a box structure measuring approximately 33m wide by 82.6m long, constructed within diaphragm wall support. The portal base slab was cast to provide a launch platform for the TBMs. Given the complex hydrogeological conditions, WJ was tasked with conducting a pumping test to gather critical groundwater data prior to designing and installing an effective dewatering system.

Key challenges included:

Managing groundwater levels to ensure safe excavation and TBM launch.
Managing groundwater levels to ensure safe excavation and TBM launch.
Operating within tight spatial constraints for additional dewatering installations post-TBM launch.

WJ’s Innovative Approach

WJ’s groundwater management strategy included:

Comprehensive Pumping Test & Data Analysis: Using site-specific hydrogeological data, we designed a highly efficient deepwell dewatering system to control groundwater levels effectively.
Cloud-Based Monitoring System: Our remote monitoring portal provided real-time access to groundwater level and flow data, ensuring both BBV’s engineering teams and WJ operators could respond proactively to changing conditions.
Adaptability in Confined Spaces: After the TBMs were launched, WJ installed additional deepwell systems in the restricted base of the portal structure, utilising our electric drilling rigs to execute precision well installations.

A Key Contribution to HS2’s Success

WJ’s expertise played a crucial role in maintaining the construction schedule for the Bromford Tunnel East Portal and Water Orton Cutting. Our ability to deliver tailored dewatering solutions, combined with real-time monitoring and expert support, ensured that excavation and TBM launch operations proceeded smoothly and efficiently.

The WJ Difference

At WJ, we provide more than just groundwater control—we deliver innovative, data-driven solutions that enable major infrastructure projects to succeed. The HS2 Bromford Tunnel East Portal project highlights our commitment to engineering excellence, adaptability, and delivering results in complex environments.

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