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.

C alpha

Secondary compression index C_alpha, dimensionless.

e p

Void ratio e_p at the end of primary consolidation.

t1

Start of creep window t1 in years.

t2

End of creep window t2 in years.

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. 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]

Ss

Secondary compression settlement in m.

• Geological models are scale-, site-, method-, and calibration-dependent. Heterogeneity, anisotropy, sampling, diagenesis, pressure-temperature history, instrument response, boundary conditions, and empirical-correlation range can dominate the result.
• 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.

• Consolidation Settlement Calculator

  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.

• Recompression Index Calculator

  Recompression (swell/reload) index Cr = Cs = (e1 - e2) / log10(sigma2' / sigma1') measured on an unload-reload loop of an oedometer test. Void ratios dimensionless, effective stresses in kPa.