CHCalcHandbook

Single Pile Capacity in Sand — End Bearing + Skin Friction

Pile Foundations · Meyerhof end bearing (Nq*) · β-type skin friction K·σ′v·tan δ · critical depth
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Pile and soil

Pile type/shape, D, L; γ, φ; groundwater; K, δ, critical depth; FS
Critical depth: σ′v is taken as constant below a depth of about L′ = 15D–20D (Vesić/Meyerhof observation). Recommended K (Das): bored pile ≈ K₀ = 1 − sin φ; low-displacement driven K₀–1.4K₀; high-displacement driven K₀–1.8K₀. δ ≈ 0.5–0.8 φ.
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Bearing capacity

Qp, Qs, Qu and allowable load
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Intermediate values

Critical depth, σ′v, Nq*, limiting end bearing, average fs
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Formulas and substitution

Calculation steps ready to paste into a report