Smart techniques cut repair time and reduce community impact
The use of a special drilling machine is slashing the time needed to replace an earthquake-damaged wastewater in South Brighton by more than 75 per cent.
Around 1300 metres of wastewater pipe are being replaced, from the corner of Mountbatten and Union Streets to the corner of Beatty Street on Estuary Road. It is taking a work crew of five as little as three days to lay 300 metre sections of pipe, whereas it would normally take around two weeks.
As well as saving time, the drilling machine is minimising surface impact. Normally an extensive trench is required to replace underground pipes to ensure sufficient clearance between the pipe and trench walls, and to allow for the placement of the new pipe and joints. To minimise disruption for the community and motorists, the Stronger Christchurch Infrastructure Rebuild Team is welding 15 meter pieces of pipe together above the ground and then inserting these underground. By using this method the team is able to get the job done using smaller trenches.
The pipes are welded in 15 metre lengths.
The replacement of this large wastewater pipe is well underway and is expected to take around seven weeks to complete, subject to construction conditions. Once the drilling, welding and pipe placement is finished, more work is required to repair the wastewater reticulation system and pump station. The broken concrete pipes are being replaced with polyethylene pipes, which are more durable and better able to withstand any future earthquake activity.
The pipe is being inserted into the trench – normally a much large trench would be required.
Polyethylene pipes are more resilient in the event of earthquakes.