Reducing Highway Maintenance Costs in Texas
Austin - Texas
Highlights
A Case Study on Geogrid Stabilisation and InSAR Analysis
The Challenge of Expansive Soils
Understanding Expansive Soils
Expansive soils, rich in clay minerals like montmorillonite, swell with moisture and shrink when dry, causing road heave and subsidence. This cycle leads to cracks, potholes, higher maintenance costs, and faster infrastructure deterioration.
Regional Impact in Texas
Texas' expansive soils, especially in the Blackland Prairie and central/eastern regions, cause inconsistent road performance. While some highways remain stable, others need frequent repairs. The challenge lies in identifying vulnerable areas and assessing stabilisation methods efficiently and cost-effectively.
The Geogrid Stabilisation Trial
Geogrid Technology
Geogrids reinforce soil and enhance pavement performance by distributing loads evenly, reducing stress, and counteracting soil movement. A Texas trial by Tensar and UT Austin tested geogrid stabilisation on highways affected by expansive soils. Accurate ground displacement and soil moisture data were crucial for evaluating its effectiveness.
Leveraging InSAR Technology
What is InSAR?
InSAR is a satellite technology that detects millimetre-level ground deformation over time, ideal for monitoring soil movement and infrastructure stability.
Why InSAR for This Project?
InSAR provided key benefits for the trial:
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Wide Coverage: Monitored the entire highway network, unlike ground surveys.
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Cost-Effective: Reduced reliance on costly on-site inspections.
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Seasonal Insights: Differentiated natural soil shifts from geogrid effects.
Insights from the InSAR Analysis
Study Methodology
For the Asprokremmos and Kouris reservoirs, satellite time series tracked chlorophyll-a and TSS levels, revealing water quality trends over time. This highly accurate method identified spatial patterns, enabled historical analysis, and helped detect early signs of degradation for proactive management.
Key Findings
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Pinpointing Vulnerable Areas
InSAR pinpointed highway sections most vulnerable to expansive soils by detecting seasonal displacement patterns, ensuring trial sites were placed in the most affected regions. -
Validating the Geogrid Solution
By comparing displacement before and after geogrid installation, InSAR confirmed its effectiveness—stabilised roads showed significantly reduced ground movement. -
Seasonal Variability
The study revealed strong seasonal soil shifts, with heave in wet periods and subsidence in dry ones. Geogrids successfully mitigated these effects, reducing overall displacement.
Implications for Highway Maintenance
Cost Savings
The trial proved that combining geogrid stabilisation with InSAR monitoring can cut highway maintenance costs. By detecting soil movement early and validating interventions, stakeholders can prevent expensive repairs and extend road lifespan.
Improved Decision-Making
InSAR’s precise, real-time data allows highway authorities to prioritise interventions efficiently, directing resources to the areas most in need.
Broader Applications
Beyond highways, these insights apply to:
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Railways: Monitoring track stability in expansive soil regions.
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Airports: Detecting ground deformation on runways.
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Urban Development: Evaluating soil stability for construction projects.
A Roadmap for Future Infrastructure Projects
The integration of geotechnical solutions with remote sensing is transforming infrastructure management. As climate change intensifies soil moisture variability, innovative approaches are increasingly vital.
Key Recommendations:
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Leverage Remote Sensing: Tools like InSAR enable proactive monitoring of ground stability.
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Invest in Prevention: Geogrid stabilisation reduces maintenance costs and extends infrastructure lifespan.
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Encourage Collaboration: Engineers, analysts, and policymakers must work together for effective, sustainable solutions.
Conclusion
Expansive soils pose a major challenge to highway infrastructure, especially in Texas. The trial by Tensar and the University of Texas at Austin showcased the power of combining geogrid stabilisation with InSAR technology.
This approach provides accurate, cost-effective insights into ground movement while validating stabilisation measures, offering a scalable solution for infrastructure management. As the demand for resilient infrastructure grows, integrating geotechnical and remote sensing innovations will be key to sustainability.
Want to learn more? Contact Geofem today to discover how InSAR can support your geotechnical needs.
