Applied-soil-displacement method (per RSPile) · COM624 soil-movement term

Piles that hold a slope: resistance vs sliding depth.

Wide-spacing pile-row demand/capacity across your supplied slip surfaces, with convergence checked on every solve — a pile-row analysis, not a global slope-stability solver.

Stabilizing piles are loaded by the moving soil, not by a head load — so the analysis imposes a free-field soil displacement profile on the p-y springs and solves for the pile response, the approach RSPile implements as its applied-displacement feature.

The method resolves lateral p-y and axial t-z resistance tangent to movement, aggregates an explicit pile count, and selects the governing supplied surface by demand/capacity. It applies to independent piles at least six diameters apart; closer spacing and automatic global slip-surface search are rejected explicitly.

Applied displacement

Free-field movement tangent to each supplied surface is resolved into lateral and axial components.

Explicit wide-spacing row

Pile count, spacing, tributary width, distributed demand, row resistance, and demand/capacity are reported.

Governing supplied surface

The largest demand/capacity ratio governs; the tool does not substitute maximum sampled resistance.

Convergence enforced

Every lateral and axial component solve must converge; unsupported close spacing is rejected explicitly.

Validated against published benchmarks

Every figure below is produced by the engine on the cited published problem — closed-form solutions, design-manual tables, or independent codes — and reproduced by the test suite on every release.

Applied soil-displacement method (RSPile)

QuantityPileCalcReferenceAgreement
Displacement resolution at 5° slip (axial / lateral, 25 mm)RSPile multi-layer slope-stabilization example2.18 / 24.91 mm2.18 / 24.91 mmexact
Lateral resistance at the 8 m slip surfaceRSPile / TZPile / LPILE607 kN582 kNwithin 4%
See the full per-tool validation report

The numbers, published

PileCalc's engine is checked term-by-term against the reference codes. A representative sample of the benchmarks — every intermediate value is visible in the app so you can reproduce them yourself.

Free-head pile (EI 1.43×10⁶, D 1 m, L 24.4 m)Liang et al. (2014) exact solution / RSPile
Max moment
792.2 kN·m
792.1 kN·m (exact)
within 0.1%
Fixed-head pile (EI 1.43×10⁶, D 1 m, L 24.4 m)Liang et al. (2014) exact solution / RSPile
Head moment
−581.1 kN·m
−581.0 kN·m (exact)
within 0.1%
Cantilever pile (EI 320, D 0.1 m, L 5.25 m)Liang et al. (2014) exact solution / RSPile
Head deflection
8.75 mm
8.750 mm (exact)
within 0.1%
Cantilever pile (EI 320, D 0.1 m, L 5.25 m)Liang et al. (2014) exact solution / RSPile
Max moment
2.335 kN·m
2.334 kN·m (exact)
within 0.1%
Circular pile, API sand (D 0.5 m, L 10 m, H 100 kN)RSPile verification manual
Deflection & moment profile
RSPile 2018 problems #1/#2/#8/#15
chart-reading tolerance
within 1–3%
Steel pile, multi-layer slope stabilization (17 m)RSPile / TZPile / LPile
Lateral resistance
607 kN
582 kN
within ~4%
Read how we validate — and why against two independent codes

Slope stabilization piles: common questions

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