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.

phi

Soil friction angle in degrees.

Rankine active earth pressure coefficient Ka = (1 - sin phi) / (1 + sin phi) for a vertical wall and level backfill. 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]

Ka

Rankine active earth pressure coefficient Ka.

• 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.

• Passive Earth Pressure Coefficient Calculator

  Rankine passive earth pressure coefficient Kp = (1 + sin phi) / (1 - sin phi) for a vertical wall and level backfill.

• Active Earth Pressure Calculator

  Rankine active lateral earth pressure sigma_a = Ka * gamma * z at a given depth behind a vertical wall with a level backfill.

• Passive Earth Pressure Calculator

  Rankine passive lateral earth pressure sigma_p = Kp * gamma * z at a given depth in front of a vertical wall with a level backfill.