SOCOTEC Monitoring Completes Tunnel Monitoring for HS2 C1 Project

Thu 07/10/2021 - 10:09

SOCOTEC Monitoring has successfully completed the tunnel monitoring element of the HS2 C1 Main Works package. 

Working on behalf of Align joint venture[i], SOCOTEC Monitoring used instrumentation and monitoring techniques to monitor ground movement underneath the M25, which forms a major section of the HS2 tunnelling route connecting the West Midlands to London.  

SOCOTEC Monitoring supplied and installed instrumentation along the C1 route, which was then used to monitor ground movement. The C1 route consists of 21.6km of high-speed rail infrastructure in a rural environment, as well as a 16.04km twin-bored tunnel with five vent shafts that handle both intervention and tunnel ventilation facilities.

Techniques implemented

A major focus of the project was the design, implementation and management of a monitoring system for junctions 16 and 17 of the M25. The system included automated patch scanning for monitoring highways assets for movement before, during and after the driving of the tunnels under the motorway interface. Monitoring prisms, wireless tilt sensors and boreholes containing automated extensometers (IPX) were also used to help monitor ground movement under the motorway.

SOCOTEC Monitoring recorded and specified the exact location of the tunnel boring machines, combining this with hourly monitoring data at every stage of the route via Calyx OMS™, the organisation’s online data visualisation system. By monitoring the tunnel portals, approaches and escape/ventilation shafts along the tunnel passage, properties along the busy route were protected, with site safety and structural integrity also maintained.

Post-construction monitoring

Each of these methods enabled SOCOTEC Monitoring to protect key assets on the 21km route, while also allowing the tunnelling team to safely proceed with the drilling operations. With all of the monitoring data now recorded, the project has now moved into the post-construction monitoring stage.

Photo credit: SOCOTEC Monitoring.

[i] Align is a joint venture of three international and privately-owned infrastructure companies, Bouygues Travaux Publics SAS, a subsidiary of Bouygues Construction, Sir Robert McAlpine and VolkerFitzpatrick, a subsidiary of VolkerWessels UK.

“We are delighted that the tunnel monitoring for the HS2 C1 Main Works Package has been so successful. Thanks to our level of expertise in terms of asset management and our implementation of state-of-the-art technologies, we are proud to have delivered the project to the best of our ability, and look forward to continuing to continuing to contribute to the HS2 C1 Main Works as the project develops.”

Jon SCOTT, Managing Director, SOCOTEC Monitoring UK.

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