Case Study

Harbury Cutting

In 2015, Harbury Cutting faced a huge failure causing a 300,000 tonne landslide

Project

Harbury Cutting

Client

Network Rail

Location

Harbury, Warwickshire

Sector

Rail

Principal Contractor

Murphy

Scope of Work

Harbury Cutting Slope Stabilisation (Emergency Response)

Specialist Contractor

Vertical Access Ltd

Geotechnical Designer

RJM

Consultant Engineer

Tony Gee & Partners

Materials Supplier

Soil Nails from Minova

The Scope

Vertical Access was already working at Harbury Cutting prior to the major failure, having been appointed to install a 290-metre catch fence as part of works associated with an earlier slip.

Following the major landslide, our involvement expanded considerably as part of the emergency response. Working alongside the wider project team, Vertical Access was tasked with specialist slope and structural stabilisation works, including soil nailing adjacent to the west portal, installation of anchors through the portal structure and specialist access works required to support and repair the damaged brickwork.

The Challenge

The scale and continuing movement of the landslide created an exceptionally challenging working environment. Ground conditions remained unstable throughout the works and required continuous monitoring to protect operatives working across the slopes and structures.

Trial drilling revealed further complexities below the surface, including significant water ingress and a vertical limestone fault line. The west portal presented its own engineering challenges, with anchors required to pass through approximately two metres of mass brickwork before reaching suitable ground beyond.

Alongside these technical challenges was an extremely demanding programme. Network Rail was working towards reopening the railway within nine weeks, requiring the emergency works to operate around the clock and adapt continuously as further information about the ground conditions became available.

Our Response

Vertical Access rapidly mobilised personnel, specialist equipment and materials from projects across the UK to support the emergency response, establishing a rolling 24/7 programme of drilling, soil nailing, meshing and structural stabilisation works.

With the slope continuing to move, monitoring and communication were fundamental to the operation. Alert systems and working procedures were established to allow teams to work safely while responding quickly to changes in ground conditions.

The stabilisation design continued to develop as information was gathered from trial drilling and the works progressed. Sulphate-resisting grout was used to provide additional durability, while diamond coring techniques enabled anchors to be accurately installed through approximately two metres of brickwork within the damaged west portal.

On the adjacent slopes, soil nails measuring up to 20 metres in length were installed to stabilise the ground. Large excavators of up to 67 tonnes, fitted with specialist TEI drilling rigs and masts, were utilised to undertake the installation. Vertical Access worked closely with Murphy to coordinate excavators, dumpers, drilling equipment and rope access personnel within the restricted and constantly changing work area.

The damaged portal also required a bespoke access solution. A custom working platform supported by Mabey System 160 brackets was developed alongside rope access techniques, allowing operatives to safely access the structure and undertake the required brickwork re-casing and stabilisation works.

The combination of specialist plant, rope access and adaptable working methods allowed multiple elements of the stabilisation programme to progress simultaneously, helping the wider project team maintain the demanding recovery programme.

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Outcome & Feedback:

The emergency stabilisation works were successfully completed within the demanding programme, securing the affected slopes and providing structural support to the damaged west portal.

Despite the scale of the landslide, challenging ground conditions and continuously evolving design requirements, the coordinated 24/7 operation enabled the railway to reopen on 13 March 2015, ahead of the planned deadline.

Vertical Access’s ability to rapidly mobilise specialist teams, equipment and access solutions played an important role in the wider emergency response, helping to restore the railway while stabilising an area affected by one of the most significant failures in Harbury Cutting’s history.

The successful delivery of the project was recognised by the wider project team, with the works receiving commendation from Mark Carne, then Chief Executive of Network Rail.

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TESTIMONIAL

“Thousands of passengers, and thousands of tonnes of freight, rely on this vital route every day. We have been working around the clock and are able to reopen the railway three weeks ahead of the original estimate.