Scope
The scope of work included:
- lowering 11 tunnels by approximately 1 metre, eight with track slabs and three featuring ballast with sleepers
- construction and installation of 477 track slabs involving 4236 Delkor units
- installation of over 1300 soil nails to reinforce the concrete walls after excavation
- installation of 12,300 tonnes of ballast
- 7800m3 of profiled earthworks within the tunnels
- construction of access tracks
- drainage works including headwalls, insitu custom pits, stormwater, reinforced concrete pipes and reinforced concrete box culverts, as well as rediverting drainage swales, and construction of outlet drainage outside the tunnels.
Outcomes
The 11 tunnels were heritage listed and approximately 100 years old,
requiring unique excavation methods to ensure the integrity of the
structures during construction. The project team worked through a range
of methodologies to ensure the effective excavation of the rock
within each of the tunnels. The selected models included using rock
breakers and profiling machines depending on which rock conditions
were present. This approach and the use of non-conventional methods of
excavation were extremely effective, resulting in no damage to the
heritage listed structures.
The successful completion of this highly complex and time critical project required fastidious planning including providing all detail regarding construction, methodology, equipment and resourcing requirements four to six weeks prior to pre-planned track closures. BMD’s project team ultimately released the tracks back to the client on time and with no lost time injuries.
