📋 Case Study
Tailings Storage Facility (TSF) Slope Reinforcement — Pilbara, Australia
Existing FoS < 1.1 under Mw 6.5 scenario; limited space for buttressing; strict environmental containment requirements
🏗️ Project Overview
Uplift and reinforcement of 30-m-high upstream TSF embankment following updated seismic hazard assessment
🎯 Challenge
Existing FoS < 1.1 under Mw 6.5 scenario; limited space for buttressing; strict environmental containment requirements
🔧 Design Approach
Geosynthetic-reinforced soil (GRS) wrap-around facing with geogrid layers + stepped internal drainage berms + automated SAR interferometry monitoring
📐 Design Diagram
AI-generated project design illustration
📐 Key Calculations
Seismic Pseudo-Static FoS
FoS = (c·L + (W − k_v·W)·tanφ) / ((k_h·W) + W·sinα)
Result: 1.04 → 1.39
Met AS/NZS 1113.1:2021 requirement
Geogrid Vertical Spacing
S_v ≤ 0.4·H·tan(45−φ/2)
Result: 0.82 m
Controlled tensile demand and strain compatibility
SAR Deformation Sensitivity
Δd_min ≈ λ/(4·sinθ)
Result: 2.8 mm
Set detection threshold for millimeter-scale creep
📊 Results
Completed in 14 weeks without interrupting ore processing; 3-year SAR data shows <1.2 mm/year cumulative displacement💡 Lessons Learned
- •GRS performance highly sensitive to placement moisture content (optimum ±2%)
- •Drainage berm geometry must account for tailings rheology—not just water
- •SAR requires stable corner reflectors installed pre-construction
✅ Key Takeaways
- 1GRS performance highly sensitive to placement moisture content (optimum ±2%)
- 2Drainage berm geometry must account for tailings rheology—not just water
- 3SAR requires stable corner reflectors installed pre-construction