Methods of test for soils, Part 33: Determination of the density in place by the ring and water replacement method

IS 2720 Part 33 (1971) - Scope & Key Specifications

This part covers in-place density determination of soil by ring and water replacement methods.

Key Reporting Requirements (Clause 5.1)

• Date, location, elevation of test
• Soil description & fraction tested
• Test method used (refer IS 2720 Part II for moisture content)
• Dry density in kg/m³ (nearest 10) or g/cm³ (2 decimals)

Important Formulas

Gradation Table (Excavated Material)

Specifications

• Use IS Sieves: 100, 80, 40, 25, 20, 10, 4.75 mm (30 cm dia) (Clause 2.12)
• Fill voids under ring with quick-setting plaster (Clause 3.2)
• Weighing scales per IS standards (beam/platform)

This ensures consistent, accurate soil density reporting for geotechnical design and quality control.

IS 2720 Part 33 - Apparatus for Density & Moisture Determination

Key Apparatus Specifications

• Moisture Content Determination: Apparatus as per IS 2720 Part 2 (1969), including oven, balance, and containers.
• Water Volume Measurement: Devices for delivering, measuring, and removing water volume in soil cavities (Clause 2.6).
• Syphon Can & Measuring Cylinders: For precise water volume measurement (Clause 2.13).
• Density Measurement Containers: Rings or containers with known volume for soil sampling.

Important Formulas

Reporting Table (Appendix A)

flowchart TD
    A[Soil Sampling] --> B[Measure Volume of Cavity]
    B --> C[Record Initial Water Volume (V1)]
    C --> D[Place Soil in Ring]
    D --> E[Record Final Water Volume (V2)]
    E --> F[Calculate Volume: V = V2 - V1]
    F --> G[Weigh Wet Soil (Ww)]
    G --> H[Determine Moisture Content (w)]
    H --> I[Calculate Wet & Dry Density]

Summary: Use IS

IS 2720 Part 33 (1971) — Key Formulas, Tables & Procedure Summary

Procedure Highlights (Clause 5.1 & Appendix A)

• Report must include:

  • Date, location, elevation of test
  • Soil description & fraction tested
  • Test method (e.g., moisture content per IS 2720 Part 2)
  • Dry density (kg/m³ or g/cm³)

• Volume of cavity determination:

• Wet density (γ):

[ \gamma = \frac{W_w}{V_c} ]

Where:
(W_w) = Weight of wet soil sample (kg)
(V_c) = Volume of cavity (m³)

• Dry density (γ_d):

[ \gamma_d = \frac{\gamma \times 100}{100 + w} ]

Where:
(w) = Moisture content (%)

Reporting Table (Appendix A format snippet)

Gradation Table (for excavated material)

Notes

• Use quick-setting plaster to fill voids under the ring (Clause 3.2).
• Clean surplus plaster and remove loose material before measurement

IS 2720 Part 33 (1971) — Key Formulas & Specifications for Density Calculation

1. Volume of Cavity (Clause 4.1)

Calculate cavity volume ( V ) by water displacement:

[ V = V_i - V_f ]

• ( V_i ) = Initial volume reading (with ring only)
• ( V_f ) = Final volume reading (with ring and cavity)

2. Dry Density Calculation (Clause 4.3 & 3.12.3)

[ \gamma_d = \frac{W_w - W_s}{V - V_s} \times \frac{100}{100 + w} ]

Where:

• ( \gamma_d ) = Dry density (kg/m³)
• ( W_w ) = Total weight of excavated material (kg)
• ( W_s ) = Weight of stones retained on sieve (kg)
• ( V ) = Volume of cavity (m³)
• ( V_s ) = Volume of stones retained on sieve (m³)
• ( w ) = Moisture content (%) of material finer than sieve (IS 2720 Part II)

3. Wet Density

[ \gamma = \frac{W_w}{V} ]

4. Reporting Requirements (Clause 5.1 & Appendix A)

• Date, location, elevation of test
• Soil description & fraction tested
• Test method used (e.g., ring and water replacement)
• Dry density to nearest 10 kg/m³ or 0.01 g/cm³
• Moisture content per IS 2720 Part II

5. Gradation Table Example

Summary Diagram (Mermaid.js)

flowchart TD
    A[Excavate Soil] --> B[Measure Weight Ww]
    B --> C[Determine Moisture Content w]
    A --> D[Measure Volume of Cavity V]
    A --> E[Separate Stones > S

IS 2720 Part 33 (1971) - Reporting of Results: Key Points

Essential Reporting Details (Clause 5.1)

• Date of test
• Test location and elevation
• Soil description
• Test method used (refer IS 2720 Part II for moisture content)
• Soil fraction tested
• Dry density reported in kg/m³ (nearest 10 kg/m³) or g/cm³ (two decimals)

Key Formulae

• Wet Density (γ):
  [ \gamma = \frac{W_w}{V} ] where:
  (W_w) = weight of wet soil (g or kg)
  (V) = volume of cavity (cm³ or m³)

• Dry Density (γ_d):
  [ \gamma_d = \frac{\gamma \times 100}{100 + w} ] where:
  (w) = moisture content (%)

Reporting Proforma (Appendix A)

• Elevation, soil description, fraction tested
• Volume measurements (initial and final readings with ring)
• Weight of container + wet soil, container alone, wet soil weight
• Moisture content and calculated densities
• Gradation table for soil particle sizes (100, 80, 40, 20, 10, 4.75 mm)

Summary Table for Density Calculation

This ensures standardized, accurate, and reproducible reporting of in-place soil density tests as per IS 2720 Part 33.

IS 2720 Part 33 (1971) - Recommended Proforma for Test Results

Key Reporting Items (Clause 5.1 & Appendix A)

• Date, Location, Elevation of the test
• Soil description
• Test method used (e.g., ring and water replacement method)
• Soil fraction tested
• Dry density (kg/m³ to nearest 10 or g/cm³ to 2 decimals)
• Moisture content (%)

Essential Formulas

Proforma Table Example

Notes