Use this geological calculation for a transparent first-pass interpretation of measured rock, soil, fluid, well, stratigraphic, isotopic, geophysical, or seismic data under an explicitly selected model.

H

Layer thickness H in m (drainage double or single as applicable to the field layer, not divided here).

e0

Initial void ratio e0, dimensionless.

Cc

Virgin compression index Cc, dimensionless.

sigma i'

Initial effective vertical stress sigma_i' in kPa.

sigma f'

Final effective vertical stress sigma_f' = sigma_i' + delta_sigma' in kPa.

Primary consolidation settlement of a normally consolidated fine-grained layer Sc = H * Cc / (1 + e0) * log10(sigma_f' / sigma_i'). Assumes virgin compression with Cc; for overconsolidated ranges use Cr instead. Thickness in m, stresses in kPa, settlement in m. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Sc

Primary consolidation settlement in m.

• Geotechnical correlations and idealized failure models depend on stratigraphy, sampling disturbance, drainage, stress history, groundwater, density, anisotropy, scale, construction sequence, and laboratory or field method. Site-specific design requires investigation and code factors.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Compare independent measurements and models, retain units and analytical metadata, propagate uncertainty, and validate interpretations against logs, cores, maps, laboratory data, or field observations.

• Compression Index Calculator

  Compression index Cc = -(de) / d(log10 sigma') = (e1 - e2) / log10(sigma2' / sigma1') from two points on the virgin consolidation curve. Void ratios dimensionless, effective stresses in kPa.

• Modulus Of Volume Compressibility Calculator

  Oedometric (constrained) modulus E_oed = (1 + e0) * d_sigma' / de = 1 / mv from a consolidation loading increment. Void ratios dimensionless, stresses in kPa.

• Secondary Compression Settlement Calculator

  Secondary (creep) settlement Ss = H * C_alpha / (1 + e_p) * log10(t2 / t1), where C_alpha is the secondary compression index from the e - log10 t tail of an oedometer test, e_p the void ratio at end of primary consolidation, and t1, t2 the creep time window in years.