Overview

CPillar is an easy-to-use software application developed by Rocscience for the stability analysis of crown pillars and laminated roof structures in underground and surface excavations. It supports three distinct limit equilibrium analysis methods: Rigid Plate, Elastic Plate, and Voussoir Plate (zero-tension arch). Users can assess pillar stability using deterministic factors of safety or probabilistic failure probabilities. CPillar allows geotechnical engineers to evaluate multiple failure modes and perform rapid assessments, supported by visual outputs and interactive modeling.

Features and Capabilities

• Analysis Methods
  • Rigid Plate analysis
  • Elastic Plate analysis
  • Voussoir Plate (zero-tension arch) analysis
  • Deterministic (Factor of Safety) or Probabilistic (Probability of Failure) analysis
  • Sensitivity analysis for critical parameters
• Failure Modes Considered
  • Shear failure (vertical sliding at supports)
  • Elastic buckling
  • Snap-through failure (arching due to gravity)
  • Localized crushing failure
• Output & Reporting
  • Save model data files
  • Export results to Excel
  • Export images or copy to clipboard
  • Generate summary views with Info Viewer
• Geometry Input
  • Define pillar width, height, length
  • Rock unit weight, overburden unit weight, water unit weight
  • Permeable or impermeable pillar assumptions
  • Voussoir arch dip angle
• User Interface
  • Customizable color schemes, fonts, and decimal precision
  • Interactive 3D model visualization
  • Instant result recalculations with parameter adjustments
• Lateral Stress Configuration
  • Constant or gravity-based stress
  • Define water table height and overburden thickness
  • Horizontal stress (sigma x/y) for constant loads
  • Kx/Ky values for gravity-induced stress
  • Optional support pressure for voussoir models
• Probabilistic Analysis
  • Calculate Probability of Failure (Pf)
  • Monte Carlo or Latin Hypercube sampling methods
  • Histograms, cumulative plots, scatter plots
  • Highlight failed cases below set safety factor
  • Plot regression trend lines
• Shear Strength Criteria Supported
  • Mohr-Coulomb
  • Generalized Hoek-Brown (GSI, mi, D inputs)
  • Generalized Hoek-Brown (mb, s, a inputs)
  • Classic Hoek-Brown