Numa Super Jaws HOV Anchoring Project

The project Retaining Wall 14/14A of the Heads of the Valley relief road works is a critical section of works to allow widening of the valley road. The anchored retaining wall, allows support for the Phi Textomur reinforced soil embankment above to allow construction of the road The challenge Keller were employed to install rock anchors, up to 13 strands and depths ranging up to 45m, with rock socket lengths of over 20m into the underlying sandstone/ironstone and mudstone rocks. The Clients designer wanted assurity in the installation through the overburden, so Keller utilised the Numa Super Jaws system to install the 220mm mild steel casing to depth. A 191mm rock socket was then formed using a Numa P60W down the hole hammer to depths up to 30m. To minimize dust, Keller employed a Manifold DTH Hammer Lubrication Unit and Foam/Mist Pump designed and built by Stratum Drilling Solutions, to dampen the air flush to reduce the dust produced by the drilling operation. Stratum also supplied the double welded casing shoes and lead lengths to ensure no damage or shoe loss during the drilling. Summary 70 Anchors with designed loads of approx. 1300kN were installed and stressed ahead of programme and on budget.