SPT Bearing Capacity Calculator (IS:2131)

Computes SPT N-value and bearing capacity parameters with IS:2131 corrections and additional research-based methods.

Depth at test (m)

Depth must be between 0 and 50 meters.

Ground water level from ground (m) — leave blank if dry

GWL must be non-negative.

Unit weight of soil (kN/m³)

Unit weight must be between 10 and 25 kN/m³.

Blows — 1st 15 cm (seating drive)

Blows must be between 0 and 100.

Blows — 2nd 15 cm

Blows must be between 0 and 100.

Blows — 3rd 15 cm

Blows must be between 0 and 100.

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Select Overburden correction method IS:2131 (approx via Pa/σ') Liao & Whitman (1986) Skempton (1986) Bazaraa & Peck (1969) Seed et al. (1985)

Atmospheric reference pressure Pa (kPa)

Pa must be between 50 and 150 kPa.

Energy ratio (ER) in %

Energy ratio must be between 30 and 100%.

Factor of Safety

FOS must be between 1 and 5.

References: IS:2131 (1981); IS:6403 (1981); Bazaraa & Peck (1969); Liao & Whitman (1986); Skempton (1986); Seed et al. (1985); Kulhawy & Mayne (1990).