Speedy shield supply for Atlanta rail underpass Oct 2020

Contact: Tyler D Sandell
Director, Business Development
email: Tyler.Sandell@KEELLC.com
Tel: +1 206 412 4234
Website: www.keellc.com

When the call came, for a digger shield needed for a live railway underpass, Kelley had the shield fully engineered, manufactured and on site in six weeks.

The task at hand was tunneling 356ft (109m) through varying stiff clays, saprolite and mylonite for a City of Atlanta water supply project. The project connects a new 3.4 billion-gallon (12.9 million m³) emergency drinking water reservoir to a new treatment plant. The most important job for the shield was to provide the required Cooper E-80 loading support for the 154ft (47m) pass under the CSX railroad with trains passing intermittently overhead with a cover as low as 15ft (4.6m).

On 1 July 2020, the Atkinson/Technique JV contracted Kelley Engineered Equipment (KEE) for the supply of the 90.25ft (2.3m) digger shield. On 15 August, just six weeks later, the machine was on site and ready to work. Averaging about four rings of liner plate or 5.3ft (1.6m) per day, the shield completed its drive on 6 October 2020.

In addition to thrust and steering systems, the unit was designed with features to expedite assembly and disassembly in the heading. After the collapsed shield was lowered down a 30ft diameter shaft, it was transported through an existing pre-lined tunnel and assembled at the face. The shield was assembled within liner panels and thrust off smaller i.d. panels that were erected within the safety of the shield.

Fabrication, assembly and factory acceptance testing was performed by KEE at the workshop of its longtime partner Wolf Hills Fabricators in Abingdon, Virginia. The Wolf Hills team was instrumental in achieving the quick delivery.

Konner Horton of Atkinson Construction thanked KEE for “a machine that worked great and for getting it done for us so quickly.”