Laboratory Testing

To

Project team

From

Daniel P. Colwell

Date

October 17, 2026

Re

Phase IV, Laboratory Testing: test assignment, results and reclassification

What is performed

Laboratory Testing measures the properties that the field can only estimate. The engineer assigns tests to representative samples from each stratum, the laboratory runs them, and the results are posted beside each sample on the boring log. The tests confirm or correct the field classification and supply the measured values used in design.

How it is performed

1. Assign the testing program. Pick representative samples from each stratum on the boring logs, weighted toward the soils that control the design.
2. Index tests. Moisture content ASTM D2216, Atterberg limits ASTM D4318, particle size ASTM D6913 and hydrometer ASTM D7928, and unit weight. Reclassify each tested sample per ASTM D2487 (USCS).
3. Strength tests. Unconfined compression ASTM D2166, unconsolidated-undrained triaxial ASTM D2850, consolidated-undrained triaxial ASTM D4767, direct shear ASTM D3080, and rock compressive strength ASTM D7012.
4. Compressibility. One-dimensional consolidation ASTM D2435 for settlement-sensitive clays.
5. Compaction and subgrade. Proctor ASTM D698 or ASTM D1557 and CBR ASTM D1883 for embankment, subgrade and pavement design.
6. Corrosion. pH, resistivity, sulfates and chlorides where buried steel or concrete will be in contact with the soil.
7. Post and review. Enter the results on Laboratory Results, check them against the field descriptions, and update the boring logs where the classification changes.

Why it matters in the workflow

Field descriptions are judgments; laboratory results are measurements. This phase checks the field work, catches misclassified soils, and supplies the tested values that give the design parameters their credibility. Without it, every parameter in Phase V would have to come from correlations and conservative assumptions.

What comes in and what goes on

Use and disclaimers

This phase guidance describes general practice for training and reference. It is not engineering advice for any project. Any value, calculation or report prepared with NANCY must be checked and accepted by a professional engineer licensed in the project jurisdiction, and governing codes, owner standards and the current editions of referenced standards take precedence. NANCY is provided as is, without warranty, and is independent of any employer or client. Use is subject to the full Use and Disclaimers.