Risky auger bore project delivered22 April 2015
UK trenchless specialist Perco has installed a 225mm sewer pipe underneath the Fairfield Golf Course off King's Road in Audenshaw to which is 5m deep a new housing development and 9m deep at the outfall located within the golf course. Perco were able to offer 2 techniques in which to install the new 225mm pipe using trenchless techniques. One option was to install the pipe using a 1200mm Pipe jack. This was the more expensive option, but posed little potential risk due the potential obstructions within the ground from the old refuge site.
The other option was to use the guided auger boring method. This would involve undertaking the bore in one length. However the unpredictable ground conditions meant that there was a considerably higher risk of failure. The client did not want to go forward with the more expensive pipe jacking option, so decided to take on the riskier auger boring option. During the piloting operations, the Perco team encountered very high skin friction & obstructions to which resulted in rescue shaft being constructed to remove obstruction.
The reduced length was then completed with Naylor Denlok Clayware being installed. Works commenced on the second length from the rescue shaft to the outfall manhole to which further obstructions were encountered along the route to which slowed down progress, these however were able to be displaced into the prevailing ground and works were successfully completed. The client said "Perco did point out the risks for us, however the house developer did not want to proceed with the reduced risk option due to the price, it goes to show that not always going for the cheaper option is right, we will always turn to Perco again for the next project".