How is Ko calculated for normally consolidated soils?

Jaky (1944): Ko(NC) = 1 - sinφ'. For NC sand with φ' = 30°, Ko ≈ 0.50. For NC clays: Ko ≈ 0.4–0.6. At-rest pressure is used for walls that cannot move (rigid basement walls, propped structures) where neither active nor passive conditions are reached. The at-rest earth pressure resultant acts at H/3 from base for uniform soil.

How does overconsolidation affect Ko?

For overconsolidated soils: Ko(OC) = Ko(NC) × OCR^sinφ' (Mayne & Kulhawy, 1982). In heavily preloaded soils, Ko can exceed 1.0. For example, a highly OC clay with OCR = 10 and φ' = 25° gives Ko ≈ 0.58 × 10^0.42 ≈ 1.54. This high lateral stress must be considered in excavation support and basement wall design.

At-Rest Earth Pressure Calculator (Ko)

Calculate the at-rest lateral earth pressure coefficient Ko using Jaky's formula for normally consolidated soils and Mayne & Kulhawy correlation for overconsolidated soils.

2D stress state at a point. All stresses in MPa.

σx — Normal Stress X (MPa)

σy — Normal Stress Y (MPa)

τxy — Shear Stress (MPa)

⚙ Mechanical Note: Results are based on standard textbook formulas and ISO/AASHTO references. Always verify critical designs with applicable codes (ISO 898, AASHTO 1993, AISC, Eurocode 3) and a qualified engineer.

How It Works

Calculate the at-rest lateral earth pressure coefficient Ko using Jaky's formula for normally consolidated soils and Mayne & Kulhawy correlation for overconsolidated soils

Each component has a specific meaning:

Jaky's formula — The jaky's formula recorded for the patient or scenario being assessed.

Note: Interpret the at-rest earth pressure ko result against the clinical thresholds and context described above.

How to Use

Enter the Jaky's formula for the patient or scenario you are assessing. Calculate the at-rest lateral earth pressure coefficient Ko using Jaky's formula for normally consolidated soils and Mayne & Kulhawy correlation for overconsolidated soils. Use the at-rest earth pressure ko result to inform your clinical assessment.

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At-Rest Earth Pressure Calculator (Ko)

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Frequently Asked Questions

How is Ko calculated for normally consolidated soils?

How does overconsolidation affect Ko?