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IIT Tirupati Navavishkar I-Hub Foundation Website
Problem Statement
Road durability depends on the integrity of subsurface layers and uniform compaction beneath the asphalt. Conventional inspection methods often miss hidden discontinuities and early signs of soil subsidence, which later lead to cracks and structural failures. A non-destructive, high-resolution survey was required to detect hidden joints, subsurface discontinuities, and potential zones of weakness in a newly constructed road at IIT Tirupati.
Overview
A Ground Penetrating Radar (GPR) survey was conducted over a 150 m² road section in the North Campus of IIT Tirupati to assess the condition of subsurface layers and detect hidden joints. A 500 MHz ultra-wideband antenna with a depth setting of 4 meters was used to capture both shallow and moderately deep structural features.
Engineering Impact
Enabled non-invasive detection of hidden transverse and longitudinal joints beneath the road.
Identified zones of soil subsidence before severe damage, supporting preventive maintenance planning.
Provided critical inputs for site monitoring, reducing future repair costs and improving road service life.
Suggested specific areas for long-term observation and priority-based repair interventions.
Conclusion
The dense-grid GPR survey with a 500 MHz ultra-wideband antenna successfully identified hidden discontinuities and early subsidence beneath the road in IIT Tirupati North Campus. Although the severity is currently low to medium, these anomalies represent potential risk zones for future asphalt cracking and should be monitored for preventive repairs. This case demonstrates the value of GPR for road condition assessment and long-term infrastructure monitoring.
Methodology
System Configuration: 500 MHz broadband antenna (250–750 MHz) for high-resolution road subsurface imaging.
Survey Design: Dense grid survey with 10 cm line spacing in both directions, enabling detailed 2D cross-sections and 3D depth slices.
Processing Workflow: Advanced GPR data processing including dewow, background removal, migration, and amplitude slice analysis was applied to resolve hidden transverse/longitudinal joints and potential subsidence zones.
Key Findings
Hidden Joints: Subtle transverse and longitudinal reflection patterns were identified below the asphalt, indicating possible construction-induced joints or discontinuities.
Soil Subsidence: Localized low-amplitude anomalies and undulating reflector patterns suggested early signs of soil subsidence from shallow depths (<1.5 m).
Cracking Indicators: Areas with subsidence corresponded to shallow cracking patterns observed on the asphalt surface. The severity was assessed as low to medium.
Continuity of Layers: Most of the road base showed uniform layering, but isolated weak zones were identified as potential risks in the long term.
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