Dr Julie Lovisa from James Cook University is using maths to determine when dredged soil is solid enough to build on.
She has developed a mathematical model that allows for greater accuracy in construction timelines and avoid costly structural failures.
“With the continual need for port expansions we are left with reclaiming land from the sea, a process that can take decades,” Lovisa said.
“But we need to be as accurate as possible in our land reclamation predictions. If we’re out by just 1%, this can mean the difference between starting construction in two or 30 years.”
Dredging is done to maintain, develop and build navigable waterways. The process creates millions of tonnes of waste each year.
Population growth, rising sea levels and port expansions have led to a parallel rise in land reclamation over the past two decades. Dredging spoil can provide the “soil” needed.
Dubai is one of the best known international examples of land reclamation. It has used the technique to create new islands, a marina and the Burq Al Hotel.
To create “new” land, dredged mud is pumped into containment paddocks erected in the ocean and dried out using a number of methods.
Depending on the conditions, the process could take anywhere between three and 10 years.
Knowing when the land is stable enough for building has been hit or miss.
“Sometimes people will just load up the soil with sand fill and hope they can build on it in a couple of years,” Lovisa said.
“But if we can nail down a date – that’s invaluable for construction timelines.”
Lovisa said another problem was that often the soil settlement was not uniform and some of the building would sink and that would lead to structural damage.
By mathematically modelling how quickly the water is squeezed from the mud, Lovisa can more accurately measure the overall settling process of the dredged mud and its stability for building.
Her model can be applied to any type of soft saturated soils that can be found along the Australian coast.
Lovisa studied land reclamation as part of her PhD.
