InfraGrid40-40C Biaxial Composite Geogrid: Karratha Salt and Potash Project

Case Studies

// Case Studies • InfraGrid40-40C

InfraGrid40-40C Biaxial Composite Geogrid: Karratha Salt and Potash Project

The Project

In the resource-rich yet challenging terrain of Karratha, Western Australia, an ambitious project was undertaken to develop a new salt and potash facility. This project was significant not only for its potential to boost the local economy but also for the technical challenges it presented, notably in constructing stable embankments within intertidal zones and areas with inherently soft soil conditions. The scope of works required innovative engineering solutions to prepare embankment foundations capable of supporting the infrastructure necessary for salt and potash production. Given the critical nature of these foundations, particularly in zones identified to have an undrained shear strength of less than 10 kPa over the top 2 meters below ground level, a robust solution was imperative. InfraGrid40-40C, a biaxial composite geogrid, was chosen for its proven performance in reinforcing soft soils and facilitating the construction of stable embankments under such challenging conditions.

Challenges

The foundational challenge of the project lay in the unique environmental and geotechnical conditions of the site. The intertidal zones and soft areas presented a set of complex variables, including high moisture content, low soil shear strength, and susceptibility to compaction and settlement issues. These conditions demanded a ground stabilization solution that could not only support the heavy loads of construction machinery but also ensure the long-term integrity of the embankment structures. The construction of embankments in such environments required a material that could improve the load distribution, enhance soil stability, and resist the dynamic forces exerted by tidal changes and construction activities. The chosen solution needed to be both effective in performance and efficient in deployment, minimizing environmental impact and facilitating the project's tight schedule.

// Our Solution

InfraGrid40-40C emerged as the exemplary solution to these challenges. Its biaxial composite geogrid structure was specifically designed to reinforce weak soils, increasing their load-bearing capacity and resistance to deformation. The installation of InfraGrid40-40C at the Karratha project involved laying the geogrid at the designated foundation areas, directly addressing the sites with undrained shear strengths below the critical threshold. Following the geogrid installation, a 500mm thick layer of embankment fill was placed and compacted with construction machinery, as specified in the project's technical requirements. The presence of InfraGrid40-40C beneath this fill layer effectively distributed the loads from the heavy machinery and the embankment itself, preventing excessive settlement and stabilizing the foundation against the lateral movements typical of soft, wet soils. The use of InfraGrid40-40C in this project not only facilitated the successful construction of critical embankment foundations but also demonstrated the geogrid's utility in overcoming the inherent challenges of building on soft, wet soils. Its deployment enabled the project team to maintain progress in line with the construction schedule, ensuring that the foundational work was completed efficiently and to the required specifications. Moreover, the application of InfraGrid40-40C contributed to the environmental sustainability of the project. By enabling the use of local fill materials and reducing the need for extensive soil replacement or chemical stabilizers, the geogrid helped minimize the project's ecological footprint. The Karratha salt and potash project stands as a testament to the effectiveness of InfraGrid40-40C in providing a robust foundation for industrial development in challenging geotechnical environments.