Highways, water, ground investigation and data – a cautionary tale

VicRoads had an ongoing problem with a section of an important arterial road in the south-east suburbs of Melbourne. The road was duplicated during 2003-2004 and had experienced over 400 mm pavement settlement and associated drainage issues, causing potential road management safety implications. Preconstruction ground investigation data provided no indication as to the likely cause. To design a solution, a conceptual engineering geological model was developed, initially using regional data and then a series of targeted ground investigations to refine the model. The provision of various types of data from a number of sources allowed the iterative development of the model and testing of a number of potential scenarios before identification of a probable cause. This paper describes the problem at the site, the model development & the eventual solution selected, as well as some learnings that were identified during the process.