Soil Nailing the A 610 at Buckland Hollow

Soil Nailing the A 610 at Buckland Hollow, Derbyshire Collaborative Project Delivery Edmond Brook AECOM Waterman Project Manager

10 years ago today…. 2

The A 610 at Buckland Hollow § § 3 Links the Derbyshire Dales with Nottingham and the M 1; Carries 14, 000 vehicles per day; Acts as a conduit for the Derwent Valley Aqueduct; River Amber lies 9 m below road at the foot of a steep slope.

The A 610 at Buckland Hollow 4

Initial response June – September 2016 § § § 5 AECOM attended site on day of callout; 10 m long translational failure; Inspection report and desk study produced; Ground investigation undertaken; Concluded that the failure posed a significant risk to road and water main.

Remediation Design Slope Stability § § § 6 Soil nails designed to BS 8006 to stabilise slope; Whole slope treated; Nail lengths chosen to simplify site works; Shorter nails at top due to services; PVC coated mesh facing.

Remediation Design Erosion Protection § § § 7 River had not caused failure, but significant risk of on going erosion; River modelling undertaken to assess peak flows; Rock rolls chosen as robust and buildable erosion protection.

Preparation for Construction January 2017 onwards § Balfour Beatty appointed as main Contractor; § CAN consulted as roped access subcontractor; § EA permits arranged by AECOM; § Himalayan Balsam devegetated prior to works to prevent seeding. 8

Preparation for Construction January 2017 onwards 9

Preparation for Construction Water Main § STW consulted over possible diversion of water § § § 10 main flows; Not possible to divert flows; DCC undertook inspection pits to locate main; Vibration limits given by STW; DCC installed instrumentation to establish baseline vibration levels from traffic; Final limits based on these values.

Construction September – October 2017 § Main Contractor – Balfour Beatty; § Sub Contractor – CAN; § Top two rows of nails installed from single § § § 11 lane closure with zero tail swing excavator; Remaining rows installed with tripod rig; Rock rolls lowered from road with excavator; Excellent feedback on design from site.

Construction September – October 2017 12

Finished Works 13

Benefits of MHA Framework § Rapid and cost effective appointment to § § 14 provide specialist services following failure; Scheme completed on budget; Construction finished 2. 5 weeks early; Early intervention prevented a potentially major infrastructure failure; Close collaboration was key to the smooth and successful delivery of the scheme.