10-year Post-Construction Retaining Wall Monitoring with InSAR

Dubai - Fujairah Freeway, UAE

The Dubai-Fujairah Freeway, a 45 km corridor through the rugged Hajar Mountains, required innovative engineering, including reinforced soil retaining walls up to 70 meters high to stabilise the highway. These walls ensure safe travel for thousands of vehicles daily. 

Marking 10 years in service, Tensar, the geotechnical firm behind their design and installation, sought to assess their long-term performance, confirming their stability and functionality over time. 

Challenges in Post-Construction Monitoring

Lack of Installed Monitoring Equipment 

A key challenge was the lack of monitoring equipment, leaving no real-time data on wall performance over the years.

Complexity of In-Situ Surveys

Without installed monitoring equipment, in-situ surveys were an option but posed challenges: 

• High Costs: Surveying 70m walls required extensive resources. ​

• Logistics: Rugged terrain and highway access issues.

• ​Safety Risks: Hazardous conditions for surveyors. ​

These factors called for a non-invasive, cost-effective monitoring solution. 

Leveraging InSAR for Retrospective Performance Monitoring 

How InSAR Works

InSAR uses satellite radar to detect ground movement with millimetric precision, identifying even the slightest displacements over time—an invaluable tool for infrastructure monitoring. 

Retrospective Analysis

A key advantage of InSAR is its ability to analyse historical satellite data. Geofem used four years of records, covering construction and post-construction, to assess the walls' performance over their 10-year lifespan.

Insights from InSAR Monitoring

The InSAR analysis confirmed the retaining walls' excellent performance, revealing: 

• Minimal Displacement: Structural integrity remained intact. 

• Consistent Performance: No significant anomalies detected. ​

• Design Validation: Tensar's engineering proved effective for long-term stability. 

The Benefits of InSAR Monitoring

Cost-Effective Solution 

A key advantage of InSAR is its ability to analyse historical satellite data. Geofem used four years of records from construction and post-construction, offering a comprehensive view of the walls' performance over 10 years. 

Non-Disruptive Monitoring

Unlike physical surveys that disrupt infrastructure, InSAR monitoring was conducted remotely, ensuring uninterrupted freeway operations and enhancing safety for surveyors. 

Safe and Efficient 

InSAR overcame terrain and traffic challenges by collecting data remotely, ensuring safety and efficiency while providing insights much faster than traditional methods. 

High Precision

InSAR's millimetric precision offered detailed insights, allowing stakeholders to make confident, informed decisions. 

Importance of Long-Term Monitoring 

This case highlights the need for ongoing monitoring of critical infrastructure. Record-breaking retaining walls face long-term stresses, including: 

• Traffic Loads: Continuous vehicle movement causes gradual deformation. ​

• Environmental Factors: Temperature shifts, rainfall, and seismic activity impact stability.​

• Material Aging: Construction materials degrade over time. 

Regular monitoring enables early issue detection, ensuring safety and functionality.

Advanced Monitoring for Infrastructure Longevity

Applications Beyond Retaining Walls 

While this case focused on retaining walls, InSAR is widely used to monitor: 

• Bridges: Detecting structural movements. ​

• Buildings: Assessing settlement or tilt. ​

• Dams: Preventing deformation-related failures.​

• Roads & Railways: Tracking subsidence or heave. 

Integrating InSAR into monitoring strategies enhances infrastructure resilience and longevity. 

Conclusion

The 10-year monitoring of the 70m retaining walls on the Dubai-Fujairah Freeway highlights InSAR’s unmatched value. Geofem’s satellite-based analysis overcame monitoring gaps and in-situ survey challenges, delivering precise insights cost-effectively. 

The results validated Tensar’s engineering excellence and set a benchmark for future infrastructure monitoring. 

As aging infrastructure faces climate and usage pressures, InSAR will be key to ensuring safety, functionality, and longevity. 

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Want to learn more? Contact Geofem today to discover how InSAR can support your geotechnical needs.