📋 Case Study

Tailings Storage Facility (TSF) Stability Assessment Post-Earthquake

Liquefaction-induced lateral spreading, slope deformation, and pore pressure buildup in saturated silty tailings

🏗️ Project Overview

Rehabilitation of TSF near Antofagasta, Chile after M7.1 event

🎯 Challenge

Liquefaction-induced lateral spreading, slope deformation, and pore pressure buildup in saturated silty tailings

🔧 Design Approach

Post-event CPTu profiling + PWP monitoring + numerical stability modeling (FLAC 2D); installation of horizontal drains and berms

📐 Design Diagram

_static = 1.32 T_v = 0.68 Challenge Drain / Sensor Berm TSF / CPTu

AI-generated project design illustration

📐 Key Calculations

Cyclic stress ratio (CSR)

0.65 × aₘₐₓ × σᵥ₀ / σᵥ₀′ × rₑ

Result: 0.23

Exceeded CRR threshold of 0.19

Factor of Safety (FS) – static

τ_f / τ_d

Result: 1.32

Marginal pre-event stability

Drainage time constant (Tᵥ)

Cᵥ × t / H²

Result: 0.68

Confirmed 90% dissipation in <14 days

📊 Results

Restored FS > 1.5 across all sections; zero seepage breakthrough over 2-year monitoring

💡 Lessons Learned

• •CPTu pore pressure dissipation curves are superior to piezometer-only monitoring
• •Horizontal drains accelerated consolidation by 3.7× vs. vertical only

✅ Key Takeaways

• 1CPTu pore pressure dissipation curves are superior to piezometer-only monitoring
• 2Horizontal drains accelerated consolidation by 3.7× vs. vertical only