The New M5 is twin underground motorway tunnels in Sydney, 9km long from Kingsgrove to St Peters with connections to Sydney Gateway and M4-M5 Link and is part of West Connex.

David was appointed to supervise a crew from Mainmark Civil at Arncliffe to carry out post grouting of the tunnels. The role required defining the scope of works, designing the extent of the grouting and completing the task to achieve an acceptanle water ingress of 6 l/min/100m.

The tunnels at Arncliffe are 17m wide and 8m high, and 30m below surface, and pass under the Cooks River.