Gas Main Slope Stabilisation

The Challenge

The Avenue Wingerworth was a 96-hectare coking & chemical plant on the edge of Chesterfield that was closed in 1992 and demolished in 2001. The site was scheduled for ground remediation from 2005. Volker Stevin were appointed in 2009 to undertake the complex task of completing this operation.

In 2016 the site suffered a significant movement of the western embankment [Zone 4A] which was connected to high levels of rainfall. Following the detailed site investigation by ESG a contract for the stabilisation was awarded by Volker Stevin to Vertical Access Ltd who along with their Geotechnical Engineers Coffey Geotechnics had provided a detailed design for soil nailing, erosion control netting and drainage works.

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The Vertical Approach: Safety, Quality, Innovation & Agility

Safety

The works were carried out using Work Restraint Systems designed and installed by the company, the team delivered the project without any safety issues and an exemplary record. The drilling work was undertaken using remote control systems that allowed the drilling operatives to be separate from the drill rig.  

Quality

The company utilised its extensive Geotechnical knowledge and evidence from trial drilling and anchor testing to give Coffey’s designers the information they required to deliver a design that could be completed within the tight timetable that would allow VSD to continue with the remediation works.

Innovation

The works were undertaken by our Geotechnical team using 35t long reach excavators operated by our own CPCS drivers that were fitted with TEI drill masts to install 587 no. 6-11m soil nails through the soft overburden, mudstone & coal seams. MacmatR erosion control matting was installed by operatives using work restraint systems.

The crest drains were 450 wide up to 1.6m deep and dug using a 6t excavator on the crest, geotextile, pipe and stone were installed. The drains were connected to pre-cast concrete chambers & brick-built catch pits.  

In order to avoid further ground contamination defensive bunds were installed around the site area.

Agility

The works were delivered by the our team without causing any delays to the main site works and in accordance with the programme.

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Outcome & Feedback

The As-Built Report for the embankment stabilisation and drainage works including the drill logs and drawing was presented to the client upon completion of the works and in accordance with the contract.

The project was also awarded The Civil Engineering Environmental Quality Assessment & Award Scheme Manual 'Outstanding Achievement' Award in 2019.