Reinforced Embankment, Peak Downs Highway (State Route 70), Australia

The Peak Downs Highway (State Route 70) is a vital artery that connects the mining and agricultural regions of Central Queensland, Australia. Due to its significance, it is frequently used by many oversized vehicles and B-double heavy trucks.

Because the highway passes through the Eton Range, considering the safety and traffic volume, the Queensland Department of Transport and Main Roads (TMR) decided to improve the road by widening it to four lanes. However, a 780-meter-long uphill section was necessary near Mackay City as a crucial part of the expansion. This section includes a significantly large S-shaped bend and demanded the construction of a 45-meter high embankment to fulfill road widening and turning radius requirements.

Considering the challenges of high slopes, massive earthwork, and extended long curves of road sections, the reinforced embankment with ACEGrid^® geogrid and steel mesh panel facing were selected as the final solution after several scheme evaluations and full-scale construction trials. This choice was due to the flexibility and adaptability of the ACEGrid^® system, which allows for easy variation of the structure's shape and promotes vegetation growth. Additionally, ACEGrid^® exhibits outstanding short and long-term performance characteristics, further supporting its selection. Given the significant height of the embankment in this project, a design analysis led to the adoption of high-strength ACEGrid^® GG150-I and GG200-I as reinforcement materials. The embankment was constructed in multiple stages, layer by layer, with a slope of 1:1. Non-woven geotextile was placed on the inner side of the steel mesh panel to prevent the backfill material from falling out.

The highway passes through forest areas, and after the completion of the project, the reinforced embankment has been in good vegetated and planting condition, enabling the project to be completed with a limited effect on the environment. This project demonstrates that the use of ACEGrid^® as a reinforced embankment can best meet the United Nations Sustainable Development Goals (SDGs), including integration with the surrounding environment, conservation of land ecosystems, energy conservation, carbon reduction, and climate crisis mitigation. The International Erosion Control Association (IECA) has awarded this project the Environmental Excellence Award.