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Skempton Clay Primary Compression Index (Cc & Cr) Calculator

Alec Skempton established the seminal correlation between Atterberg Liquid Limit and virgin consolidation slope Cc.

Atterberg liquid limit percentage

Initial undisturbed in-situ void ratio

Calculated Result
0.405

Compression Index (Cc)

Recompression Index (Cr)

0.0405

Calculation Breakdown

  1. Skempton Empirical CorrelationCc = 0.009 · (LL - 10) => 0.405

Cc vs Liquid Limit

Interactive visualization based on your current inputs

Cc
0.00.30.50.81.0LL = 35% (Low)LL = 55% (Medium)LL = 85% (High)Liquid Limit LL (%)Index Cc

What Is the Skempton Clay Primary Compression Index (Cc & Cr) Calculator?

Alec Skempton established the seminal correlation between Atterberg Liquid Limit and virgin consolidation slope Cc.

It allows geotechnical engineers to estimate primary consolidation settlement before laboratory oedometer testing completes.

How Does the Skempton Clay Primary Compression Index (Cc & Cr) Calculator Work?

The calculation evaluates user-provided measurements using recognized domain equations, converts between measurement units, and adjusts for real-world efficiency factors.

Skempton Clay Primary Compression Index (Cc & Cr) Calculator Formula & Variables

The core mathematical equation utilized by this calculator is expressed as:

C_c = 0.009 (LL - 10), \quad C_r \approx 0.1 C_c

Skempton empirical formula for undisturbed clay compression index.

How to Use the Skempton Clay Primary Compression Index (Cc & Cr) Calculator

  1. Enter your primary measurements in the input fields above.
  2. Select your preferred units (e.g. metric or imperial) if applicable.
  3. Review or adjust operational assumptions such as field efficiency.
  4. Click Calculate to instantly generate the full results breakdown and visual chart.
  5. Use the Reset button at any time to clear the form and test a new scenario.

Step-by-Step Example Calculation

Marine Clay Consolidation Parameter

Input Values:

liquidLimitLlPct:65.0
inSituVoidRatioE0:1.25

Understanding Your Result

Your calculated result represents the realistic operational capacity or baseline output under the specified conditions. Comparing theoretical and effective outputs reveals the direct impact of turns, overlap, and practical downtime.

Factors That Affect the Result

Field terrain, operator experience, equipment maintenance, overlap margin, and weather conditions can significantly influence real-world output.

When Should You Use This Calculator?

Use this calculator whenever you need quick, verified estimates for job planning, budgeting, equipment sizing, or project timelines.

Assumptions & Limitations

  • Valid for normally consolidated inorganic clays of moderate to high plasticity.

Frequently Asked Questions

Calculation Accuracy & Reference Note

This calculator implements verified, deterministic mathematical equations based on published standards. Results should be treated as professional engineering estimates; always verify critical operations with local equipment manuals and site inspections.

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