Slope Stability (Method of Slices) — Ebora

⛰️ Slope Stability

Factor of safety of a slope along a circular slip surface by the method of slices — Ordinary / Fellenius, Bishop's Simplified and Janbu's Simplified (with the f₀ correction), side by side. Auto-slicing of a simple slope, a per-slice table, a scaled slope-and-circle diagram, worked steps and a PDF report.

⛰️ Free for Ebora students · try many trial circles · Balance … EP

Method (headline)

All three (Fellenius, Bishop, Janbu) are computed and compared; the headline highlights your choice.

Slope & soil

Slope height H (m)

Slope angle β (deg)

γ (kN/m³)

c′ (kPa)

φ′ (deg)

Pore-pressure ratio r_u

u = r_u·γ·h on each slice base (r_u = 0 for a dry/drained slope). The toe is the origin (0, 0); the slope rises to the right (crest at x = H/tanβ). A valid slip circle is centred up and to the right (e.g. x_c ≈ 5, y_c ≈ 15, R ≈ 16 for the defaults).

Trial slip circle

Centre x_c (m)

Centre y_c (m)

Radius R (m)

Number of slices

Pick the circle so it daylights through the slope. If it doesn't intersect the ground in two points the app will tell you to adjust the centre/radius.

📘 Factor of safety

Fellenius

—

Bishop

—

Janbu (×f₀)

—

Per-slice table

Worked solution

⚠️ Teaching tool — one homogeneous soil and one trial circle at a time. The critical FS is the minimum over many trial circles; vary the centre and radius to search for it. Confirm against your course method and code before any real design.