What is the typical compaction requirement for road embankments?

Generally 95-97% of the Maximum Dry Density (MDD) as determined by the relevant lab test, usually IS 2720 (Part 8).

How often should I perform field density tests?

As a guide, one test per 1000 m³ for earth fill/embankments or one test per 500 m² for subgrade layers. Project specifications may vary.

What are the common methods for checking field compaction?

The Sand Replacement Method (IS 2720 Part 28) for all soil types and the Core Cutter Method (IS 2720 Part 29) for fine-grained cohesive soils.

IS 10379

: 1982

Code of practice for standard penetration test (SPT) for soils

CurrentFrequently UsedCode of PracticeGeotechnical · Surveying and Geotechnical Investigation

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This standard provides guidelines for the field control of moisture content and compaction of soils during the construction of earthworks and pavements. It specifies the necessary tests, equipment, frequency of testing, and acceptance criteria to ensure the required soil density is achieved on site.

Lays down the procedure for conducting the Standard Penetration Test (SPT) in soils to assess their density and strength characteristics.

Quick Reference Values

Minimum compaction for subgrade/embankments95% to 97% of MDD

Permissible moisture content variation from OMC±1% to ±2%

Frequency of field density tests for fill/embankment1 test per 1000 m³

Frequency of field density tests for subgrade1 test per 500 m²

Key Formulas

ρd = ρb / (1 + w) — Calculation of Dry Density from Bulk Density (ρb) and Water Content (w)

Practical Notes

Selection between light compaction (IS 2720 Part 7) and heavy compaction (IS 2720 Part 8) for determining lab MDD depends on the expected field compaction effort (e.g., heavy rollers for roads vs. light rollers for general fill).

Ensure the sand used in the Sand Replacement Test is clean, dry, uniformly graded, and properly calibrated to avoid significant errors in density measurement.

The frequency of testing should be increased at the start of a project, when the soil type changes, or if compaction equipment is changed.