Introduction
Fully-thread anchors have become a key solution in stabilizing slopes in mountainous terrain and landslide-prone regions. Their ability to transfer tensile loads to deeper, competent ground makes them ideal for challenging topographies. Through real-world case studies, this article highlights performance, design adaptation, lessons learned, and best practices.
Case Study 1: Stabilization of Highway Cut Slope — Western Ghats, India
Background
A national highway section in the Western Ghats faced recurrent shallow landslides during monsoon seasons. The soil profile consisted of weathered laterite and weak clayey layers.
Solution
- Fully-thread anchors with 10–12 m length
- Anchor spacing: 2 m × 2 m grid
- Shotcrete facing to protect the slope surface
- Drainage berms and sub-surface drains installed
Results
- Significant reduction in slope movement
- No major slide reported in subsequent monsoons
- Monitoring showed anchor loads remained stable after installation
Key Takeaways
- Adequate drainage design is as important as anchor installation
- Shotcrete integration enhances performance
Case Study 2: Landslide Remediation at Railway Embankment — Eastern Himalayas
Background
A rail section passing through steep weathered slopes was repeatedly affected by translational landslides due to intense rainfall and seismic activity.
Strategy
- Fully-thread anchors (12–15 m) inclined at 15–20°
- Combination of mesh and shotcrete for surface protection
- Instrumentation (load cells and inclinometers) installed
Outcomes
- Slope deformation reduced by over 70 % within 6 months
- Instrument readings indicated load redistribution over time
Lessons Learned
- Instrumentation aided optimized maintenance
- Adjusted anchor inclination improved load transfer in highly weathered soil
Case Study 3: Rural Road Cut Slope Stabilization — Andes Mountains
Background
A rural road cut slope in the Andes showed signs of deep‐seated failure due to seasonal rainfall and high gradient.
Design Features
- 14 m fully-thread anchors with high-strength grout
- Sub-horizontal drainage layers installed
- Progressive benching to reduce slope angle
Performance
- No significant distress in slope after two wet seasons
- Improvement attributed to combined anchor and drainage solution
Engineering Insight
- Anchors alone are effective, but performance improves substantially with hydrology control
Case Study 4: Urban Landslide Protection — Pacific Northwest, USA
Site Conditions
- Residential hillside above critical infrastructure
- Clay/silt soils with deep fracturing
Approach
- Hybrid design: Fully-thread anchors + micropiles
- Shotcrete with fiber reinforcement
Results
- Permanent deformation reduced
- Homeowners reported long-term slope stability
Best Practice
- Hybrid systems can compensate where anchors alone are marginal
Comparative Observations Across Cases
| Aspect | Common Lessons |
| Design Depth | Deeper anchors (>10 m) perform better in fractured ground |
| Drainage | Essential for long-term stability |
| Instrumentation | Improves maintenance decisions |
| Surface Protection | Shotcrete/mesh aids in erosion control |
| Seismic Zones | Safety factors must be increased |
Performance Trends and Monitoring
In most cases:
- Anchor loads tend to settle with time after initial grouting
- Periodic load checks help identify issues early
- Proper drainage reduces loads significantly
Conclusion
The reviewed case studies demonstrate that when properly designed and implemented, fully-thread anchors significantly enhance slope stability in mountainous and landslide-prone areas. Critical success factors include:
- Proper site investigation
- Effective drainage design
- Integration with surface protection
- Ongoing monitoring
These combined efforts lead to safer infrastructure and reduced risk of slope failure in challenging environments.
