Free Web Tool

Slope Stability Bishop

Single trial-circle stability factor of safety using Bishop’s simplified method — for preliminary slope assessment.

Inputs

Slope Height H (m)

Slope Angle β (°)

Cohesion c' (kPa)

Friction φ' (°)

Unit Weight γ (kN/m³)

Pore pressure ru0 = dry, 0.4 typical wet

Number of slices

Trial radius factorR = factor × H

Method — Bishop's simplified

FoS = Σ[ (c'b + (W − ub)tanφ')/mα ] / Σ(W·sinα), mα = cosα + sinα·tanφ'/FoS.
Iterates from FoS=1.0; converges in 4–6 cycles.
Single trial circle — toe-circle approximation. Use trial radius × height.
For full stability search, use commercial slope-stability software.

Results

Failure circle R—

Centre (xc, yc)—

Driving Σ(W·sinα)—

Resisting (numerator)—

FoS Bishop—

Status—