Project Sheet: Arkwright Street, Wall Stabilisation

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Client

  • Virador

Contractor

  • Sonic Drilling Ltd (Sub-Contractor to Costain Ltd)

Works Undertaken

  • slope stability runs
  • design of soil nails
  • production of Contract Drawings & Specification
  • production of Designers Health & Safety Risk Register
  • review of soil nail test data
  • production of as-built drawings

Description of Project

Virador proposed to construct a waste management facility on an area of land adjacent to Arkwright Street in Manchester.

In order to construct the facility, the ground level needed to be raised behind an existing masonry retaining wall. The wall was showing no signs of distress, but the increased surcharge on the wall meant that stabilisation was necessary.

GroundSolve Ltd were approached to design soil nails (anchors) which would be installed into the retaining wall for stability. Prior to the designing work, the ground conditions and the depth of the existing foundations needed to be determined. To do this, a site investigation was carried out involving the excavation of hand dug trial pits.

The stability of the existing wall and the slope behind, hence the required anchor force was determined using OASYS SLOPE.

In total, 96 nails were installed, ranging between 6 and 10.9 meters in length. They were installed at different heights and inclinations to gain maximum strength according to the ground conditions.

To limit the visual impact of the works the holes for the soil nails were cored through the wall, which enabled the masonry facing to be reinstated following installation of the nails.

It was required to have a design life of 60 years, requiring the exposed elements of the anchors to be galvanised with zinc based anti-corrosion paint. To protect the buried elements, a general soil aggressivity assessment was undertaken showing that the soil was mildly aggressive requiring a much thicker layer of galvanising for corrosion protection.

The wall during the construction process
The wall during the construction process
Insertion of the anchors into the existing retaining wall
Insertion of the anchors into the existing retaining wall