Repair works to a collapsed Victorian culvert presented a number of logistical and engineering challenges.
The project involved the repair of a collapsed section of 1.9m diameter Victorian brick drain located 12m beneath a road and directly below a high pressure water main.
Following a conditions assessment, some 300 tonnes of soil was excavated and a new section of pipe-jacked culvert constructed. A new spray concrete lining was also built within the 125m of the culvert which had not collapsed.
A sheet pile coffer dam was installed in the upstream valley to protect the culvert from flooding during works. A 10.5m diameter, 13m deep shaft was then built alongside the location of the drain, and a tunnel driven from the shaft to access the culvert.