Microtunneling Under Main Western Railway
The ULX was required to be 59m long. A Ø700mm diameter microtunnel for was required to install a Ø500mm Humes (Holcim) S-Series RC jacking pipe. Railcorp required the works to be carried out during a weekend rail shutdown in conjunction with scheduled railway maintenance. The ground was saturated high plasticity clay.
The rail shutdown was scheduled from midnight Friday until midnight Sunday. It was planned to microtunnel the first 16m prior to the shutdown. The remaining 43 m would be microtunelled (with 2 crews working consecutive 12 hour shifts) and the annular space between the pipes and the microtunnel grouted during the shutdown.
Good progress and Zero Settlement of the Rails
Wade Engineering excavated the shaft and the jacking frame was established in the days prior to the weekend. The first 16m was microtunelled by the end of the Friday. Railcorp delayed the start of the shutdown until 5am Saturday morning. Microtunnelling commenced in torrential rain. Progress was good and the drilling completed by the 2nd crew at 4pm on the Saturday afternoon. The head was disconnected and the rods removed.
The annular gap was grouted on Sunday 24th. Amid the continuing heavy rain over the next few days the conduits were pushed and the grout around the conduits was poured. The Surveyor observed zero settlement of the rails.
Vacuum tanks and vacuum truck postioned during microtunnelling
Humes S-Series being prepared for Jacking
Jacking Pipe and Rod assembly being lowered into shaft
Services being prepared to be passed through the jacking pipe
Pipejacking in progress
Nearing the end of the stroke