Subsidence in Road Infrastructure Embankments Monitored with InSAR

A road infrastructure crossing a mixed urban and rural area was continuously monitored using InSAR technology to analyze ground displacement over time. The monitored corridor included several critical components — bridges, valleys, rivers, and extensive embankments. The InSAR data revealed distinct structural behaviors between bridge decks, which remained stable, and adjacent embankments, which showed significant subsidence. The study aimed to understand deformation trends and assess potential impacts on structural integrity.

Objective

To demonstrate how continuous InSAR monitoring enables the identification of differential settlement and lateral soil movements in road infrastructures, supporting early detection of instability and ensuring long-term structural safety.

Analysis Focus

Vertical movement (subsidence and uplift)
Horizontal movement (lateral displacement)
Derived indicators - displacement rate, change in rate of movement, and total accumulated deformation

Key Findings

Bridge decks and abutments remained stable, with displacements below 5 mm/year
Adjacent embankments experienced significant settlement, exceeding 150 mm over two years
The instability was associated with geotechnical foundation soil behavior, not the bridge structure
Analysis of points on both sides of the bridge showed vertical displacement patterns aligned with surrounding slopes, suggesting lateral compression effects
Horizontal decomposition revealed tangential ground movements, indicating compression and lateral spreading, which can lead to additional stress on abutments and pavement layers

**Overview of the Monitored Road Corridor** Vertical displacement along the road: red = subsidence, blue = uplift.

**Comparison Between Deck and Embankment** Bridge deck stable; embankment shows progressive settlement.

**Displacement on Both Sides of the Bridge** Greater movement concentrated in the access embankments.

**Horizontal Displacement Vector Decomposition** Opposing lateral movement patterns across the road corridor.

Deformation Summary

Structural Element	Vertical Displacement	Horizontal Movement	Stability Assessment
Bridge Deck	<5 mm/year	Negligible	Stable
Bridge Abutments	<5 mm/year	Slight lateral compression	Stable
Embankments	Up to 150 mm (2 years)	Tangential spreading	Significant settlement
Adjacent Slopes	50–120 mm	Lateral compression	Moderate instability

What Could Have Been Done

A regular monitoring and analysis routine (monthly or biweekly) could have:

Detected abnormal vertical and horizontal displacement trends early
Supported the implementation of timely inspection or corrective actions
Prevented stress accumulation on bridge structures and progressive deformation along embankments

If InSAR data had been analyzed systematically, settlement acceleration could have been detected in time to implement mitigation measures before significant deformation occurred.

Conclusion

This case study highlights:

The effectiveness of InSAR monitoring in detecting both vertical and horizontal ground deformation
The importance of combining vertical and horizontal displacement analysis for a full structural assessment
The need for continuous geotechnical monitoring to ensure safety, durability, and performance of road infrastructures

Value Proposition

Implementing the Geotechnical Management Module with periodic InSAR analysis:

Enables early detection of differential settlement and lateral deformation
Improves decision-making for maintenance and safety management
Promotes a preventive, data-driven approach to infrastructure monitoring

Last Featured

See all case studies

arrow_outward