Retaining Wall Stability

Cantilever Retaining Wall Stability Analysis

Stability checks for cantilever retaining walls: sliding, overturning, eccentricity, and bearing pressure. Aligned with ACI SP-17 Ch. 2 and Rankine active-pressure theory (Das & Sivakugan 2019, §16.3 & §17.4–17.7; Bowles 1996, Ch. 12).

Modeling assumptions (current build): Backfill is on the heel side only; toe side is bare (no passive resistance credited); soil is dry/moist with hydrostatic pressure ignored; surcharge is taken as a uniform strip load on the full heel width; active (Rankine) earth pressure with vertical wall back and horizontal backfill (α = 0). Verify these match the site condition before using results.

Wall Geometry

Height Above Ground, h₁ (m)

Height Below Ground, h₂ (m)

Stem Thickness, t_stem (m)

Base Thickness, t_base (m)

Total Base Width, b (m)

Toe Width, b_toe (m) — explicit

Heel Width, b_heel (m)

Front Soil Depth, y (m)

Credit passive resistance from front soil (default ON)

Toe-Corner Cut Distance, x_cut (m)

Toe-Corner Cut Angle, θ_cut (deg)

Soil & Material Properties

Soil Unit Weight, γ_s (kN/m³)

Soil Friction Angle, φ (deg)

Soil-Concrete Friction Coefficient, μ

Allowable Soil Bearing, q_all (kPa) — optional

Concrete Unit Weight, γ_c (kN/m³)

Surcharge, q (kPa) — positive only

Top-of-Toe Applied Loads (mid-toe)

Optional point loads applied on the top of the base slab at a user-specified horizontal distance. Sign convention: H > 0 in the active direction (toward the toe), V > 0 downward, M > 0 in the overturning sense. Negative values flip the direction.

x_load — horizontal distance from toe corner (m)

H_top — horizontal force (kN/m)

V_top — vertical force (kN/m)

M_top — applied moment (kN·m/m)

Show Design Summary as absolute values (recommended)

References & Methodology

Das, B.M. & Sivakugan, N. (2019). Principles of Foundation Engineering, 9th Edition, SI. Cengage Learning. Ch. 8 — Vertical Stress Increase in Soil (§8.4–8.5 line/strip loads, §8.12 Westergaard); Ch. 16 — Lateral Earth Pressure (§16.2 K₀, §16.3 Rankine active, §16.7 Coulomb, §16.8 surcharge, §16.11 Rankine passive p. 676); Ch. 17 — Retaining Walls: §17.2 Proportioning Retaining Walls (p. 697, Fig. 17.4) — the toe / stem / heel / shear-key geometry convention used by this calculator; §17.3 Application of lateral earth pressure theories (p. 698); §17.4 Stability of Retaining Walls (p. 699); §17.5 Overturning check (p. 701); §17.6 Sliding-along-base check (p. 703, Table 17.4 for δ values); §17.7 Bearing-capacity-failure check (p. 706); §17.10 Gravity retaining-wall design for earthquake conditions (p. 720).
Poulos, H.G. & Davis, E.H. (1980). Pile Foundation Analysis and Design. John Wiley & Sons. Ch. 2 covers the effective-stress concepts (γ' below the water table) used in the toe-side passive resistance and front-soil overburden calculations; Ch. 7 on lateral loading of single piles is the theoretical backdrop for the soil–structure interaction at the wall–soil contact.
ACI Committee 318 (2019). Building Code Requirements for Structural Concrete (ACI 318-19). American Concrete Institute.
ACI Committee SP-17 (2014). The Reinforced Concrete Design Handbook — Chapter 2: Cantilever Retaining Walls. ACI.
Bowles, J.E. (1996). Foundation Analysis and Design (5th ed.), Chapters 11–12. McGraw-Hill.
Rankine, W.J.M. (1857). On the stability of loose earth. Phil. Trans. Royal Society of London, 147.
NAVFAC (1986). Design Manual 7.02 — Foundations and Earth Structures, Ch. 3 (Surcharge influence: Boussinesq/Westergaard solutions, Fig. 1).
AASHTO (2020). LRFD Bridge Design Specifications, §10.6 — Spread footings (sliding, eccentricity, bearing pressure).