Argillaceous Swelling Rocks - Methods for Laboratory Testing

IS 14396 Part 1: Sampling, Storage & Preparation of Test Specimens - Key Points

1. Sampling Method

• Use core borings (double/triple tube, ~100 mm dia) or block sampling.
• Preserve natural density & water content using air pressure or anti-swelling admixture (e.g., Antisol).
• Wrap samples in waterproof liner + aluminium foil, seal with paraffin wax.
• Label with location, depth, elevation.
• Transport in cushioned containers, avoid frost/extreme heat.

2. Storage

• Minimize storage time.
• Store at constant 27°C.
• Avoid sunlight and moisture fluctuations.

3. Specimen Preparation

• Prepare ≥3 specimens per sample; one as reference for water content, specific gravity, saturation.
• Shape: Right circular disc, diameter 50-100 mm, thickness 20-30 mm.
• Machining with air-cooling or anti-swelling medium; avoid recoring.
• For fragile argillaceous rocks, use Annex A trimming method with a manual press and stainless steel confining ring.

4. Reporting Requirements (Clause 5.1)

Include in report:

• Unique ID, origin, lithology, sampling & testing dates.
• Storage & preparation methods.
• Orientation, dimensions, density, water content, saturation.
• Test temperature, preload, water specs.
• Axial stress vs time and axial stress vs swelling strain plots.
• Maximum axial swelling stress.

Apparatus for Axial Swelling Stress (Fig. 1)

Specimen Dimensions & Preparation Summary

flowchart TD
    A[Sample Collection] --> B

IS 14396 Part 1-4: Maximum Axial Swelling Stress

Key Formulas:

1. Axial Swelling Strain (ε_ax):
   [ \varepsilon_{ax} = \frac{\delta_{ax}}{h} ]

• (\delta_{ax}) = axial displacement
• (h) = original specimen thickness

2. Radial Swelling Strain (ε_rad):
   [ \varepsilon_{rad} = \frac{\delta_{rad}}{d} ]

• (\delta_{rad}) = increase in specimen circumference (A_c) divided by initial circumference (measured with stainless steel band)
• (d) = initial specimen diameter

Determining Maximum Axial Swelling Stress:

• Axial swelling stress is correlated with axial swelling strain and can be derived from stress-strain curves obtained during testing.
• Typically, maximum axial swelling stress corresponds to the peak stress recorded during free swelling under axial restraint.

Additional Specifications:

• Measure initial and final water content, density, and degree of saturation to characterize swelling behavior.
• Use Part 3 for free swelling strain data as input.
• Use Part 4 to relate swelling strain to axial swelling stress.

Summary Table:

flowchart LR
    A[Specimen Preparation] --> B[Measure Initial Dimensions]
    B --> C[Swelling Test]
    C --> D[Measure Axial Displacement (\delta_{ax})]
    C --> E[Measure Circumference Increase (A_c)]
    D --> F[Calculate \varepsilon_{ax}]
    E --> G[Calculate \varepsilon_{rad}]
    F & G --> H[Plot Stress vs Strain]
    H --> I[Determine Maximum Axial Sw

IS 14396 Part 1-4: Key Formulas for Axial and Radial Free Swelling Strain

1. Axial Swelling Strain (ε_ax)

[ \varepsilon_{ax} = \frac{\delta_{ax}}{h} ]

• δ_ax = axial displacement (change in specimen thickness)
• h = original thickness of the specimen

2. Radial Swelling Strain (ε_rad)

[ \varepsilon_{rad} = \frac{\delta_{rad}}{d} ] or equivalently, [ \varepsilon_{rad} = \frac{\Delta C}{C_0} ]

• δ_rad = radial displacement (change in diameter)
• d = initial specimen diameter
• ΔC = increase in specimen circumference (measured with stainless steel band)
• C₀ = initial circumference of specimen

3. Additional Parameters

• Calculate density, initial and final water contents, and degree of saturation for comprehensive swelling characterization.

Summary Table:

flowchart TD
    A[Specimen] --> B[Measure initial thickness (h) and diameter (d)]
    B --> C[Apply water for swelling]
    C --> D[Measure axial displacement (δ_ax)]
    C --> E[Measure increase in circumference (ΔC)]
    D --> F[Calculate axial strain ε_ax = δ_ax / h]
    E --> G[Calculate radial strain ε

IS 14396 Part 1-4: Axial Swelling Stress vs. Axial Swelling Strain

Key Formulas:

1. Axial Swelling Strain (ε_ax):
   [ \varepsilon_{ax} = \frac{\delta_{ax}}{h} ]

• (\delta_{ax}) = axial displacement
• (h) = original specimen thickness

2. Radial Swelling Strain (ε_rad):
   [ \varepsilon_{rad} = \frac{\delta_{rad}}{d} ]
   or alternatively,
   [ \varepsilon_{rad} = \frac{\Delta C}{C_0} ]

• (\delta_{rad}) = radial displacement
• (d) = initial specimen diameter
• (\Delta C) = increase in specimen circumference (measured with stainless steel band)
• (C_0) = initial circumference

3. Axial Swelling Stress (σ_ax):

• Determined experimentally as a function of axial swelling strain, often plotted as a stress-strain curve.
• Maximum axial swelling stress is obtained from Part 2 of the code.

Specifications:

• Measure axial displacement and specimen dimensions accurately.
• Calculate initial and final water content, density, and degree of saturation for correlation.
• Use stainless steel band method for circumference changes.

Summary Table:

graph LR
A[Measure axial displacement \(\delta_{ax}\)] --> B[Calculate \(\varepsilon_{ax} = \delta_{ax}/h\)]
C[Measure circumference change \(\Delta C\)] --> D[Calculate \(\varepsilon_{rad} = \Delta C / C_0\)]
B --> E[Plot \(\sigma_{ax}\) vs \(\

Scope Summary - IS 14396 Parts 1-4 (Key Points & Formulas)

Scope (Clause 1.1):

• Measures axial swelling strain to reduce axial swelling stress in radially constrained rock specimens immersed in water.
• Applicable where similar boundary conditions exist.

Key Formulas (Part 4)

Apparatus Specifications (Annex B & C)

• Stainless Steel Ring: Polished inner surface, thickness 5-10 mm, limits radial strain ≤ 10⁻⁴.
• Porous Metal Plates: Stainless steel or drilled plates with 0.1 mm holes for water flow.
• Loading Plate: Rigid, with central indentation for sphere.
• Loading Frame & Piston: Capable of stepwise load application, load measured with ±0.5% accuracy.
• Micrometer Dial Gauges: Sensitivity 2.5 microns to measure axial displacement.
• Cell: Water-filled to cover specimen assembly.

Test Conditions & Reporting (Clause 5.1)

• Ambient temperature: 27 ± 2°C
• Specimen dimensions: Diameter and thickness measured with ±0.1 mm accuracy.
• Loads applied stepwise, typically halving load each step down to 25 kPa.
• Report includes specimen ID, origin, preparation, density, water content, saturation, test temperature, and plots of axial stress vs strain/swelling strain.

Graphical Representation

graph LR
A[Specimen in Stainless Steel Ring] --> B[Porous Metal Plates (Top & Bottom)]
B --> C[Loading Plate with Sphere]
C --> D[Loading Frame & Piston]
D --> E[Load

IS 14396 Part 1-4: Apparatus and Equipment - Key Points

Apparatus Components (Annex B & C)

• Stainless Steel Ring: Rigid radial restraint; polished inner surface; thickness 5-10 mm; max radial strain ≤ 10⁻⁴.
• Porous Metal Plates: High modulus (preferably porous stainless steel or drilled stainless steel plates with 0.1 mm holes); one above and one below specimen.
• Loading Plate: Stainless steel, thick enough for rigid strain application; with a central indentation for a loading sphere.
• Loading Frame & Piston: Adjustable loading frame with a polished steel sphere (2 cm dia) to apply incremental loads up to 10 kN.
• Micrometer Dial Gauges: For precise displacement measurement.
• Load Measuring Device: To record applied axial load.

Key Formulas (Part 4)

• Cross-sectional Area, A: [ A = \frac{\pi}{4} d^2 ] where ( d ) = specimen diameter.

• Axial Stress, (\sigma): [ \sigma = \frac{N}{A} ] where ( N ) = axial force.

• Axial Strain, (\varepsilon): [ \varepsilon = \frac{\Delta h}{h_0} ] where ( \Delta h ) = axial displacement, ( h_0 ) = original specimen thickness.

Test Environment & Procedure Highlights

• Temperature: Maintain at 27 ± 2°C.
• Specimen measurements: Diameter and thickness measured at multiple points with ±0.1 mm accuracy.
• Loading: Stepwise, typically 50% decrements, down to ~25 kPa.
• Water: Distilled or site-specific water for immersion.
• Reporting: Include specimen ID, origin, dimensions, density, water content, saturation, temperature, loading, and stress-strain plots.

Reporting Graphs

• Axial Stress vs Elapsed Time (Fig. 2A)
• Axial Stress vs Compensated Swelling Strain (Fig. 2B)
• Axial Stress vs Total Axial Strain (Fig. 1)

flowchart TD

IS 14396 Part 1-4: Test Procedures Key Points

1. Rounding Off (IS 2:1960)

• Final test values must be rounded to same significant figures as specified values.

2. Apparatus (Annex B, Fig. 1)

• Stainless Steel Ring: Rigid radial restraint, thickness 5–10 mm, max radial strain 10⁻⁴.
• Porous Metal Plates (2 pcs): High modulus, porous stainless steel or drilled holes (~0.1 mm diameter).
• Loading Plate: Stainless steel, above specimen.
• Loading Frame & Piston: Rigid frame with adjustable loading device, piston with hemispherical end.

3. Test Report Requirements (Clause 5.1)

• Sample ID, origin, lithology, mineralogy, pore water chemistry.
• Sampling & testing dates, storage & sealing methods.
• Specimen orientation, dimensions, density, water content, saturation degree.
• Test temperature, preload, water specs.
• Plots:
  • Axial stress vs elapsed time (Fig. 2A).
  • Axial stress vs compensated swelling strain (Fig. 2B).
• Maximum axial swelling stress (max stress to maintain specimen height).
• Optional: Total compensated swelling strain.

4. Key Diagrams

graph LR
A[Loading Frame] --> B[Loading Piston]
B --> C[Loading Plate]
C --> D[Upper Porous Plate]
D --> E[Specimen inside Stainless Steel Ring]
E --> F[Lower Porous Plate]
F --> G[Base Support]

Summary Table: Apparatus Components

This ensures standardized, reproducible swelling stress tests for soil specimens per IS 14396 Part 1

Key Formulas from IS 14396 Part 1-4 for Calculations and Data Analysis

1. Axial and Radial Swelling Strain

• Axial swelling strain, ( e_{ax} ): [ e_{ax} = \frac{\delta_{ax}}{h} ] where ( \delta_{ax} ) = axial displacement, ( h ) = original specimen thickness.

• Radial swelling strain, ( e_{rad} ): [ e_{rad} = \frac{\delta_d}{d_0} \quad \text{or} \quad e_{rad} = \frac{\Delta C}{C_0} ] where ( d_0 ) = initial specimen diameter, ( \delta_d ) = radial displacement, ( \Delta C ) = increase in circumference.

2. Cross-sectional Area of Specimen, ( A ):

[ A = \frac{\pi}{4} d^2 ] where ( d ) = specimen diameter.

3. Axial Stress, ( \sigma ):

[ \sigma = \frac{N}{A} ] where ( N ) = measured axial force.

4. Total Axial Strain:

[ \varepsilon_{total} = \varepsilon_{instantaneous} + \varepsilon_{swelling} ]

Reporting Requirements

• Unique specimen ID, origin, lithology, mineralogy, sampling/testing dates.
• Specimen dimensions, density, water content, degree of saturation (initial and final).
• Test temperature and water specifications.
• Plots:
  • Axial stress vs elapsed time (Fig. 2A)
  • Axial stress vs compensated swelling strain (Fig. 2B)
  • Axial stress vs total axial strain (Fig. 1)

Apparatus Specifications (Summary)

• Stainless steel ring with 5-10 mm thickness, polished inner surface.
• Porous metal plates (stainless steel or drilled plates with 0.1 mm holes).
• Loading plate with hemispherical loading sphere.
• Load frame with continuous load adjustment.

graph TD
A[Specimen] -->|Axial Load| B[Loading Plate]
B --> C[Porous Plates (Top & Bottom)]
A -->

Reporting of Results per IS 14396 (Parts 1-4):

Key Specifications for Test Reports (Clause 5.1)

• Sample ID & Specimen ID
• Geographic origin, lithology, fabric, mineralogy, and pore water chemistry
• Sampling & testing dates and methods
• Specimen sealing, storage, and preparation methods
• Orientation relative to anisotropy and in-situ directions
• Specimen dimensions (diameter, thickness)
• Density, water content, specific gravity, degree of saturation (initial & final)
• Test temperature and water specifications for immersion
• Applied preload (Part 4)
• Plots:
  • Axial swelling strain vs time (Part 1)
  • Axial stress vs time and axial stress vs compensated swelling strain (Part 4)
• Maximum axial and radial swelling strains/stresses
• Volumetric strain (computed or by liquid displacement)

Important Formulas

Reporting Rounding (IS 2:1960)

• Round off test results to the same number of significant digits as specified in the standard.

Illustrative Diagram: Axial Stress vs Time & Strain

graph LR
    A[Start Test] --> B[Apply Seating Load]
    B --> C[Measure Axial Force & Displacement]
    C --> D[Plot Axial Stress vs Time (Fig. 2A)]
    C --> E[Plot Axial Stress vs Compensated Swelling Strain (Fig. 2B)]
    D --> F[Determine Max Axial Swelling Stress]
    E --> G[Calculate Compensated Swelling Strain]
    F --> H[End Test]
    G --> H

This

IS 14396 (Parts 1-4): Apparatus & Key Formulas for Measuring Axial Swelling Stress

Apparatus Components (Fig. 1 & 3):

• Stainless Steel Ring: Rigid radial restraint; polished inner surface; thickness 5-10 mm; max radial strain ≤ 10⁻⁴.
• Porous Metal Plates (2): Porous stainless steel or drilled stainless steel plates with small holes (~0.1 mm dia); one above and one below specimen.
• Loading Plate (3): Stainless steel, rigid, with indentation for loading sphere.
• Loading Frame (7 or 6): For applying and maintaining load.
• Loading Piston/Rod (8): Hemispherical end or separate sphere to rest on loading plate.
• Micrometer Dial Gauges (5): Sensitivity 2.5 microns to measure axial displacement.
• Load Measuring Device (6): Electromechanical load cell, ±0.5% accuracy.
• Specimen Cell (4): Filled with water above specimen.

Key Formulas (Part 4):

Testing & Reporting Essentials:

• Specimen dimensions measured with ±0.1 mm accuracy.
• Test temperature: 27 ± 2°C.
• Water used: distilled or site-specific.
• Load applied stepwise; typical decrements 50%.
• Record axial stress vs elapsed time (Fig. 2A) and axial stress vs swelling strain (Fig. 2B).
• Report includes specimen ID, origin

Apparatus for Measuring Axial Swelling Strain (IS 14396 Part 1-4)

Key Components (Fig. 1, Part 2 & 3)

• Stainless Steel Ring: Rigid radial restraint; thickness 5-10 mm; polished inner surface.
• Porous Metal Plates: Two plates (above & below specimen), porous stainless steel or drilled holes (~0.1 mm dia).
• Loading Plate & Frame: Stainless steel loading plate with hemispherical loading piston; rigid frame with adjustable loading device.
• Micrometer Dial Gauges: Two gauges, sensitivity 2.5 microns, measure axial displacement.
• Load Measuring Device: Electromechanical load cell, ±0.5% accuracy.
• Cell: Water-filled container holding specimen assembly.
• Stainless Steel Band: Thin (0.1 mm) flexible band for radial strain measurement.

Important Specifications

• Test Temperature: 27 ± 2°C
• Specimen Dimensions: Thickness and diameter measured at multiple points (±0.1 mm accuracy).
• Water: Distilled or site water; chemical composition noted.
• Measurement Sensitivity: Displacement 2.5 microns; load accuracy ±0.5%.

Key Formulas (Clause 4.1)

Test Reporting Requirements (Clause 5.1)

• Unique specimen ID, origin, lithology, mineralogy.
• Sampling & testing dates, storage method.
• Specimen orientation, dimensions.
• Initial & final density, water content, degree of saturation.
• Test temperature, preload, water specifications

IS 14396 Part 1-4: Committee Composition Summary

Committee Responsible:

• Rock Mechanics Sectional Committee, CED 48 (Annex D)

Key Details on Committee Composition

Rock Testing Subcommittee (CED 48:2)

• Convener: Dr. A. K. Dhawan (Central Soil and Materials Research Station)
• Members include representatives from Indian School of Mines, IIT Delhi, CSIR labs, Hydraulics Engineering Instruments, and power corporations.

Notes on Standards Compliance

• Rounding off test results per IS 2:1960 rules.
• Final values must retain the same significant figures as specified.

Summary Diagram: Committee Structure

graph TD
    A[Rock Mechanics Sectional Committee CED 48]
    A --> B[Chairman: Dr. Bhawani Singh]
    A --> C[Member Secretary: Dr. R. P. Kulkarni]
    A --> D[Members from Govt., Academia, Research Institutes]
    A --> E[Rock Testing Subcommittee CED 48:2]
    E --> F[Convener: Dr. A. K. Dhawan]
    E --> G[Members: IIT, CSIR, Power Corps, Instruments]

This committee ensures expert consensus and technical rigor in rock mechanics testing standards per IS 14396.