Code of practice for thin-walled tube sampling of soils
1986 Edition

Overview of Scope & Essential Specifications

• Scope: Establishes methods for obtaining relatively undisturbed soil samples via thin-walled tube techniques during boring.
• Data Recording: All field observations during drilling and sampling must be documented as per the provided proforma (Appendix A).
• Critical Data to Capture:
  • Borehole identification, coordinates, drilling method, elevation.
  • Groundwater levels, drilling water loss, zones of excess pressure.
  • Sampling tube identification, cleaning methods, depths, penetration lengths, signs of disturbance.
  • Detailed soil description including texture, color, and consistency.
• References: Definitions aligned with IS 2809-1972.
• Additional Items: Sample labels, data sheets, and shipping containers as specified.

Sample Data Recording Fields (Appendix A)

flowchart TD
    A[Start Boring] --> B[Log Borehole Details]
    B --> C[Monitor Water Levels]
    C --> D[Perform Thin-Walled Tube Sampling]
    D --> E[Record Sampling Details]
    E --> F[Document Soil Characteristics]

This ensures all essential details are systematically recorded following IS 2132 guidelines.

Key Reference Points and Data Logging as per IS 2132

• Detailed Proforma (Clause 5.1 & Appendix A): Specifies comprehensive formats for recording observations during undisturbed soil sampling.
• Data to Include:
  • Borehole specifics: coordinates, drilling techniques, elevation, casing usage, operator details.
  • Groundwater and drilling water loss observations before and after casing installation.
  • Sampling details: tube numbers, cleaning procedures, timings, penetration depths, sample lengths, disturbance evidence, soil descriptions.

Important Considerations:

• The recording format is extensive but may be adjusted for specific site conditions.
• Some data fields can be omitted for open trial pit sampling, with sampling directions noted.
• Terminology follows IS 2809-1972 definitions.

Summary Table of Sampling Data

Contact Information:

• Regional and branch offices for standard procurement and inquiries are listed.

This detailed approach guarantees reliable soil sample documentation for geotechnical assessments.

Equipment and Materials Overview According to IS 2132

Thin-Walled Sampling Tubes (Clause 3.3)

• Must comply with specifications of IS 11594-1985.
• Made from stainless steel or copper.
• Designed for undisturbed soil sample collection.

Ancillary Items (Clause 3.5)

• Includes labeling materials, data sheets, and shipping containers.
• Ensures proper sample identification and protection.

Data Recording Requirements (Clause 5.1 & Appendix A)

• Mandatory detailed logging during boring and sampling.
• Key parameters to record:
  • Borehole number, location coordinates, drilling method, surface elevation.
  • Water level monitoring before and after casing insertion.
  • Sampling details such as tube number, depth, penetration, sample length, and soil description.
• Use the prescribed proforma to ensure systematic data capture.

Essential Data Parameters Summary

flowchart TD
    A[Begin Boring] --> B[Record Borehole Details]
    B --> C[Measure Water Levels]
    C --> D[Insert Thin-Walled Tube]
    D --> E[Log Sampling Data]
    E --> F[Withdraw Sample and Describe Soil]
    F --> G[Label and Store Sample]
    G --> H[Complete Data Sheet]

References:

• IS 2132: Soil Sampling Procedures
• IS 11594-1985: Thin-walled tube specifications
• IS 2809-1972: Definitions related to soil sampling

This ensures consistent and reliable soil sampling and documentation.

Essentials of Sampling Procedure as per IS 2132

• Standard Tube Sizes: Sampling tubes adhere to four indigenous standard sizes (Clause 2.1).
• Sampler Head Compliance: Must meet IS 11594-1985 specifications (Clause 3.2).
• Piston Sampler Use: Recommended for very loose saturated sandy, silty soils, and clays according to IS 10108-1982.
• Sampling Frequency:
  • At every stratum change or a maximum interval of 1.5 meters.
  • Interval can be extended up to 3 meters if vane shear or standard penetration tests are conducted between samples (Clause 4.3.5).
• Timing: Sampling should be conducted immediately following borehole clean-out without delay or overnight gaps (Clause 4.3.2).
• Data Rounding: Final test values must be rounded following guidelines in IS 2-1960, maintaining the specified significant digits (Clause 0.4).

Summary Table for Sampling Intervals

Referenced Standards

• IS 11594-1985: Sampler head specifications
• IS 10108-1982: Piston sampler practices
• IS 2-1960: Numerical rounding rules

flowchart LR
    A[Commence Sampling] --> B{Is Clean-out Completed?}
    B -- Yes --> C[Proceed with Sampling]
    B -- No --> D[Delay Not Permitted]
    C --> E{Is There a Stratum Change?}
    E -- Yes --> F[Sample Immediately]
    E -- No --> G{Is Distance Less Than 1.5m?}
    G -- Yes --> H[Sample]
    G -- No --> I{Are Vane Shear or SPT Tests Conducted?}
    I -- Yes --> J[Interval Up to 3m]
    I -- No --> K[Maintain 1.5m Interval]

This procedure ensures collection of representative and minimally disturbed soil samples.

Key Aspects of Field Notes and Data Logging per IS 2132

Observations in the Field (Clauses 4.3.6 & 4.3.3)

• Document groundwater table details including:
  • Water table depth.
  • Elevations where drilling water is lost.
  • Zones of elevated water pressure.
• Record:
  • Borehole bottom depth relative to ground surface.
  • Penetration depth of sampling tube under own weight plus rods.
  • Water levels in borehole before, during, and after casing use.

Data Recording (Clause 5.1 & Appendix A Proforma)

• Utilize the prescribed proforma to capture:
  • Project and borehole specifics (coordinates, drilling methodology, elevations).
  • Water level observations (pre/post casing, mud usage).
  • Sampling details including tube number, cleaning process, penetration depth, sample length, recovery ratio, and soil characteristics.
• Attach labels on sampling tubes with:
  • Tube number, job identification, sample location, borehole number, sample number, penetration depth, and gross recovery ratio.

Vital Parameters to Record

Sample Label Template (Clause 4.5.1)

Tube Number: _______
Job Identification: _______
Sample Location: _______
Borehole Number: _______
Sample Number: _______
Penetration Depth: _______ m
Gross Recovery Ratio: _______ %

flowchart TD
    A[Initiate Drilling] --> B[Record Surface Elevation]
    B --> C[Log Groundwater Levels]
    C --> D[Deploy Sampling Tube]
    D --> E[Record Penetration and Water Levels]
    E --> F[Withdraw Sample and Measure Recovery]
    F --> G[Label Sample Tube]
    G --> H[Complete Observation Proforma]

Comprehensive field documentation facilitates quality assurance in soil sampling.

Guidelines for Sample Handling, Sealing, and Transport per IS 2132

Sample Preparation and Bedding (Clauses 4.4 & 4.4.4)

• Store samples in shaded areas to protect from direct sunlight.
• Position samples on a moist bedding made of sand, jute fabric, or sawdust.
• Cover the samples with the same moist bedding material to maintain moisture content.
• This procedure helps prevent moisture loss and preserves sample condition during storage and transit.

Labeling and Shipping (Clauses 4.5 & 3.5)

• Each sample container must have clear labeling indicating:
  • Sample identification number.
  • Date and time of collection.
  • Geographic location.
  • Associated data sheets.
• Use robust, sealed shipping containers to avoid damage or contamination.
• Containers should maintain environmental conditions to preserve samples (e.g., moisture, temperature).

Sealing

• Seal samples immediately after collection to prevent contamination or moisture loss.
• Employ airtight caps or seals appropriate for the sample type.

Summary Table for Sample Handling

flowchart LR
    A[Sample Collection] --> B[Seal Immediately]
    B --> C[Place on Moist Bedding]
    C --> D[Cover with Moist Bedding]
    D --> E[Label Sample Container]
    E --> F[Pack in Sturdy Shipping Container]
    F --> G[Ship Maintaining Sample Conditions]

This ensures sample integrity from collection through testing.

Reporting Requirements and Data Formats per IS 2132

Data Logging (Clause 5.1 & Appendix A)

• All data gathered during boring and sampling must be recorded onsite using the detailed proforma.
• The proforma includes:
  • Project and borehole identification (coordinates, drilling method, elevations).
  • Water level observations (before/after casing, excess pressure zones, mud usage).
  • Sampling operations (tube number, cleaning method, sampling date/time).
  • Sample specifics (penetration depth, pushing method, sample length, recovery ratio, soil description).
  • Remarks and exceptional observations.

Labeling Requirements (Clause 4.5.1)

Sample labels must display:

• Tube number.
• Job designation.
• Sample location.
• Borehole number.
• Sample number.
• Penetration depth.
• Gross recovery ratio.

Gross Recovery Ratio (GRR) Formula

[ \text{GRR} = \frac{\text{Length of Soil Sample Recovered}}{\text{Tube Penetration Length}} \times 100% ]

Summary Table for Reporting

Workflow Diagram

flowchart TD
    A[Start Boring] --> B[Record Borehole Info]
    B --> C[Monitor Water Levels]
    C --> D[Conduct Sampling]
    D --> E[Document Sampling Data]
    E --> F[Label Sample Tubes]
    F --> G[Compile Report]
    G --> H[Submit and Archive Data]

Adhering to this framework ensures compliance with IS 2132 reporting standards.

IS 2132 Appendix A: Standardized Format for Recording Observations

Field Observations (Clause 4.3.6)

• Document water table information including groundwater level, zones of lost drilling water, and excess water pressure elevations.
• Record temporal changes during sampling.

Data Reporting (Clause 5.1 & Appendix A)

• Complete the standard proforma fully during boring and sampling operations.

Proforma Sections Overview

Tube Labeling Details (Clause 4.5.1)

• Tube number
• Job designation
• Sample location
• Borehole number
• Sample number
• Penetration depth
• Gross recovery ratio

Sample Data Example

flowchart TD
    A[Begin Borehole Drilling] --> B[Record Water Levels]
    B --> C[Prepare for Sampling]
    C --> D[Insert Sampling Tube]
    D --> E[Document Sampling Details]
    E --> F[Label Sample Tubes]
    F --> G[Complete Field Log Sheet]

Summary: Employ this detailed proforma to ensure thorough recording of all drilling and sampling observations, with particular attention to water table and sample integrity.