Slope Stability Calculator

Grounded in mass wasting mechanics (Q1567542) and debris flow dynamics (Q1817963)

Infinite Slope Model

Calculate Factor of Safety (FoS) using Bishop's simplified infinite slope method. FoS = (c' + σ'·tanφ') / τ, where σ' = effective normal stress and τ = shear stress driving failure. Based on factor of safety (Q2034862).

Context: Chongqing Collapse Response

On July 18, 2026, a hillside collapse in Chongqing, China killed eight and left 34 missing. This calculator applies the same mechanics that govern such failures: debris flow initiation, pore pressure buildup, and the critical angle where cohesion fails.

  • Daily Pioneer: Eight Dead, 34 Missing After Chongqing Hillside Collapse
  • Wikidata Q1567542: Mass wasting — geomorphic process by which soil, sand, regolith, and rock move downslope
  • Wikidata Q1817963: Debris flow — water-laden masses of soil and fragmented rock rushing down mountainsides
  • Wikidata Q2034862: Factor of safety — defining formula n=S/T, the ratio of capacity to demand

Worked Example

Weiser Prairie Edge Case: θ=25°, z=3m, γ=18.5 kN/m³, c'=12 kPa, φ'=32°, WC=15%

1.42
Factor of Safety
28.7 kPa
Shear Strength
20.2 kPa
Driving Stress

✓ STABLE — Margin exceeds 1.3 safety threshold

Field Verification

NASA PIA10337: Landslides exposing stratified terrain

NASA PIA10337 — Public Domain
Stratified failure planes visible in Martian analog terrain

Related Work