Method of measurement of building and civil engineering works, Part 25: tunnelling
1971 Edition

Overview of IS 1200 Part 25 (1971) – Scope and Measurement Details

• Scope: This section defines standardized measurement techniques for grouting procedures, particularly pack and pressure grouting related to concrete lining in tunnels.

• Measurement Criteria:

  • Grouting quantities are determined by the weight of cement injected into drilled holes.
  • Additional materials such as stone dust are measured independently in their loose, dry form using calibrated containers.

• Measurement Accuracy (Clause 2.3):

  • Linear measurements to the nearest 0.01 m
  • Surface areas to the nearest 0.01 m²
  • Volumes to the nearest 0.01 m³
  • Weights to the nearest 0.1 kg

Measurement Accuracy Summary

Important Notes:

• Cement weight is the primary basis for grout quantification.
• Stone dust and additives are measured separately before mixing.
• Measurements reflect net quantities after installation.

flowchart TD
    A[Grouting Activities] --> B[Measure Cement Weight]
    A --> C[Measure Stone Dust and Additives]
    B --> D[Weight recorded in kg (nearest 0.1)]
    C --> E[Loose dry volume via approved boxes]
    D & E --> F[Total Grouting Quantity]

IS 1200 Part 25: Core Principles and Definitions for Tunnel Work Measurement

This part focuses on the measurement methodology specifically for tunneling operations. Key highlights include:

Fundamental Principles:

• Measurements reflect the actual executed work on-site.
• Excavation volumes are expressed in cubic meters (m³), while lining and surface areas are in square meters (m²).
• Measurement techniques adhere to guidelines established in IS 1200 Part II (1974) for civil engineering tasks.

Specifications:

• Excavation: Net volume after accounting for overlaps or material bulking.
• Supports and Linings: Surface area excluding any overlapping sections.
• Handling Overbreaks and Underbreaks: Adjustments made according to site measurements.

Typical Measurement Table:

Volume Calculation Formula for Excavation:

[ V = A \times L ]

• (V): Excavation volume (m³)
• (A): Cross-sectional tunnel area (m²)
• (L): Tunnel length (m)

flowchart TD
    A[Tunnel Excavation] --> B[Determine Cross-Section Area (A)]
    B --> C[Measure Tunnel Length (L)]
    C --> D[Calculate Volume: V = A × L]
    D --> E[Subtract Overbreak Volume]
    E --> F[Final Excavation Quantity]

Note: Refer to IS 1200 Part II (1974) for comprehensive measurement rules relevant to tunnel work.

IS 1200 Part 25: Excavation Quantification Methods for Tunnels

Essential Guidelines & Calculations

• Excavation Volume (Clause 3.3):
  Measure the volume within the designated 'B' line (pay line) specified by the supervising engineer, irrespective of actual digging extents.
  [ \text{Excavation Volume} = \text{Cross-sectional area within 'B' line} \times \text{Tunnel length} ]

• Extended Excavation (Clause 3.3.2):
  Any excavation exceeding the initial 'B' line should be measured distinctly for the additional volume between the initial and new boundaries.

• Site Description (Clause 2.7):
  Record geological strata, terrain features such as ridges or valleys, and tunnel gradient for precise volume assessment.

Measurement Workflow

1. Define the 'B' line cross-section (pay line).
2. Calculate cross-sectional area (A) inside the 'B' line.
3. Multiply by tunnel length (L): [ V = A \times L ]
4. If excavation extends beyond 'B' line, measure additional volume separately.

Area Calculation Examples

flowchart LR
    A[Define 'B' Line] --> B[Calculate Cross-Sectional Area]
    B --> C[Multiply by Tunnel Length]
    C --> D{Is Excavation Beyond 'B' Line?}
    D -- Yes --> E[Measure Additional Excavation Volume]
    D -- No --> F[Record Excavation Volume]

IS 1200 Part 25: Guidelines for Measuring Tunnel Supports

Measurement Basis

• Temporary Supports: Calculated by the area supported, which equals the perimeter length multiplied by the tunnel's linear length.
• Permanent Supports: Measured by total weight (kilograms) encompassing all constituent parts.

Components Included in Permanent Support Weight

• Steel structural sections (riveted or welded)
• Lagging materials, butt and feather plates
• Fasteners including bolts, nuts, dowels, wedges, tie rods, spikes, and drift pins
• Temporary timber spreaders
• Concrete pedestals (if applicable)
• Blocking and backfilling with excavated debris

Important Considerations

• Any reinforcement or enhancement of existing supports via added components is quantified separately.
• Weight measurements cover all connecting and fastening elements comprehensively.

Measurement Summary

flowchart LR
    A[Support Structures] --> B[Temporary Supports]
    A --> C[Permanent Supports]

    B --> D[Measured by Area]
    D --> E[Perimeter × Tunnel Length]

    C --> F[Measured by Weight (kg)]
    F --> G[Steel Sections + Fasteners + Plates]
    F --> H[Timber Spreaders + Concrete Pedestals + Backfilling]

This method guarantees precise accounting for supports during tunneling projects.

IS 1200 Part 25: Procedures for Measuring Concrete Lining in Tunnels

Volume Measurement (Clause 5.1)

• Measure the volume of concrete between the formwork (or the external surface of steel shells) and the pay line ('B' line).
• Include the volume of formwork itself.
• Do not subtract the volume occupied by reinforcement bars.
• Deduct the volume of permanent steel supports from the total concrete volume.

Precast Concrete Blocks (Clause 4.5)

• Precast concrete blocks used as lagging are measured independently.
• Their volume is deducted from concrete lining volume when located within the 'B' line.

Overbreak Concrete (Clause 5.1.1)

• Concrete used to fill excavation overbreaks beyond the 'B' line is included within the main or primary concrete lining volume.

Grouting Over Concrete Lining (Clause 4.5)

• Grout filling between the 'B' line and precast or steel lining is measured based on cement weight.
• This includes both manual and mechanical placement techniques.

Summary Table: Inclusion and Deduction in Concrete Volume

Concrete Volume Formula:

[ V = \text{Concrete volume between formwork/steel shell and 'B' line} - \text{Permanent steel supports volume} ]

flowchart LR
    A[Formwork or Steel Shell Outer Surface] --> C[Define Inner Boundary of Concrete]
    B['B' Line (Pay Line)] --> C[Define Outer Boundary of Concrete]
    D[Permanent Steel Supports] -->|Volume Deducted| C
    E[Reinforcement] -->|Volume Not Deducted| C
    F[Precast Blocks] -->|Measured Separately| C

IS 1200 Part 25: Guidelines for Measuring Pack and Pressure Grouting Over Concrete Lining

Key Measurement Details

• Grout Holes (Clause 6.1):

  • Length of grout holes drilled through concrete or rock measured in running meters.
  • For holes drilled through steel liners, count the number of holes.

• Grouting Quantification (Clause 6.4):

  • Based on the weight of cement in the grout injected into holes.
  • Stone dust and other additives measured separately in loose dry conditions using approved containers.

• Concrete Filling for Overbreaks (Clause 5.1.1):

  • Concrete filling beyond the 'B' line is accounted for within the primary lining volume.

• Grouting Behind Supports (Clause 4.3):

  • Measured by the weight of cement utilized, including materials consumed.

Typical Grout Volume Calculation

[ \text{Grout Volume} = \pi \times r^2 \times L ]

Where:

• (r) = radius of grout hole (meters)
• (L) = length of grout hole (meters)

Cement Weight Calculation

[ W_c = V_g \times \rho_g \times C_f ]

Where:

• (W_c) = cement weight (kg)
• (V_g) = grout volume (m³)
• (\rho_g) = grout density (kg/m³)
• (C_f) = cement proportion in grout mix

Measurement Units Summary

flowchart TD
    A[Drill Grout Holes] --> B[Measure Hole Length (m)]
    B --> C[Inject Grout]
    C --> D[Record Cement Weight (kg)]
    C --> E[Record Additives Volume]
    D --> F[Calculate Total Grout Volume and Materials]

Refer to IS 1200 Part 25 and related cement standards for detailed procedures.

IS 1200 Part 25: Guidelines for Quantifying Pumping and Dewatering Efforts

Key Measurement Details (Clause 2.5)

• Each pumping phase, including intermediate stages, should be measured separately.
• Units of measurement differ by pumping type:
  • Electrical pumping: Kilowatt-hours (kW·h) or brake power hours (bp·h).
  • Pneumatic pumping: Measured by the rated capacity of the compressor in cubic meters of air delivered per hour.
  • Special pumping (non-electric): Measured in kilolitres (kL) or kilowatt-hours of water when applicable.

Measurement Rules

• Each stage is recorded independently.
• Pneumatic pumping quantification is based on air volume delivered.
• Grouting measurement (Clause 6.4) is based on cement weight injected; stone dust and additives are measured separately in loose dry form.

Summary Table for Pumping Measurement

This facilitates precise tracking and billing of pumping and dewatering activities.

IS 1200 Part 25: Procedures for Measuring Water Pressure Tests in Tunneling

Key Points:

• Clause 6.3: Each water pressure test must be measured and recorded separately for every individual hole.

• Clause 6.4: Grouting quantities are measured by the actual weight of cement injected into holes.

  • Additives such as stone dust are measured separately in their loose dry condition using calibrated boxes.

Units of Measurement:

• Water pressure testing: per hole basis.
• Grouting cement: kilograms or tonnes.
• Additives: volumetric measurement in loose dry state.

Additional Notes:

• Pumping measurements (Clause 2.5) include:
  • Electrical pumping: kW·hours or brake power hours.
  • Pneumatic pumping: cubic meters of air per hour.
  • Special pumping without electricity: kilolitres or kW·hours.

Summary Table

Conceptual Procedure Flow

flowchart TD
    A[Start] --> B[Identify Holes Individually]
    B --> C[Conduct Water Pressure Tests]
    C --> D[Record Test Data Per Hole]
    D --> E[Prepare Grout Mix]
    E --> F[Measure Cement Weight]
    F --> G[Measure Additive Volumes]
    G --> H[Inject Grout into Holes]
    H --> I[Record Injection Quantities]
    I --> J[Complete Measurement Process]

For comprehensive details, consult IS 1200 Part II (Cement and Concrete Works) alongside this standard.

IS 1200 Part 25: Guidelines on Booking Dimensions and Rounding

Dimension Booking (Clause 2.2)

• Dimensions should be recorded consistently in the sequence:
  Length → Width → Height/Depth/Thickness

Measurement Precision (Clause 2.3)

Rounding Instructions (Clause 0.6)

• Follow rounding guidelines according to IS 2-1960.
• Maintain the number of significant digits as specified in the standard.
• Round off all final measured or computed values accordingly.

Additional Notes

• Special pumping measurements are recorded separately in kilolitres or kilowatt-hours (Clause 2.5).
• Measurements denote net quantities based on fixed-in-place work.
• Consistency in booking and rounding minimizes disputes and fosters uniformity.

flowchart LR
    A[Start Measurement] --> B{Is Booking Order Correct?}
    B -- Yes --> C[Record Length → Width → Height/Depth]
    C --> D[Record Precise Values]
    D --> E[Apply Rounding per IS 2-1960]
    E --> F[Finalize Recorded Dimension]

This process ensures standardized recording and billing in tunneling and civil engineering projects.

IS 1200 Part 25: Categorization of Tunnel Excavation Items

Main Categories (Clause 3.1)

• a) Hard Rock Excavation:
  • Excavation requiring no support structures.
• b) Soil or Soft/Hard Rock Excavation:
  • Excavation necessitating temporary or permanent supports (refer to IS 1200 Part 1 for soil classification).

Note: Support structures are measured separately as per Clause 4.

Important Site Description (Clause 2.7):

• Document geological strata, terrain features such as ridges and valleys.
• Note the tunnel’s inclination angle.

Measurement Principles:

• Excavation quantities are measured by volume.
• Supports are accounted for separately.
• Follow general civil engineering measurement rules.

Tunnel Excavation Classification Summary

This classification facilitates clear measurement and billing based on ground conditions and support needs.

IS 1200 Part 25: Procedures for Measuring Overbreaks

Overbreak Measurement (Clause 3.3.1)

• Overbreak volumes outside the designated 'B' line should be measured separately.
• Overbreaks caused by negligence or carelessness, as certified by the Engineer-in-Charge, are excluded from separate measurement.

Concrete Filling for Overbreaks (Clause 5.1.1)

• Concrete placed to fill overbreaks beyond the 'B' line is included within the main or primary concrete lining quantity.

Grouting Measurement (Clause 6.4)

• Grouting quantities are measured by the weight of cement injected.
• Additives such as stone dust are measured separately in their loose dry form using approved containers.

Overbreak and Grouting Measurement Summary

Practical Guidance:

• Engineer-in-Charge certification is mandatory for classifying overbreaks.
• Use scales for cement weight and volumetric boxes for additives.
• Overbreak volume = Excavated volume minus design volume within 'B' line.

flowchart LR
    A[Excavation] --> B{Is Overbreak Present?}
    B -- Yes --> C[Measure Overbreak Volume Separately]
    B -- No --> D[Include in Main Lining Volume]
    C --> E{Cause of Overbreak?}
    E -- Negligence --> F[Exclude from Separate Measurement]
    E -- Otherwise --> G[Include in Measurement]
    G --> H[Concrete Filling Measured with Lining]
    F --> D

This approach ensures proper billing and quality assurance in tunnelling operations.

IS 1200 Part 25: Measurement Protocols for Timber and Precast Concrete Lagging

Key Specifications

• Precast Concrete Lagging (Clause 4.5):

  • Volumes of precast concrete blocks are measured separately.
  • Their volume is deducted from the concrete lining volume if located within the 'B' line.
  • Refer to IS 1200 Part II (Concrete Works) for concrete lining measurement details.

• Supports (Clause 4.3):

  • Measured by weight (kg), including steel sections, lagging materials, bolts, and nuts.

• Timber Lagging (Clause 4.3.1):

  • Measured separately by volume or as per IS 1200 Part XXI (Woodwork).

Typical Measurement Methods

Reference Standards

• IS 1200 Part II – Concrete Works
• IS 1200 Part XXI – Woodwork

flowchart TD
    A[Lagging Measurement] --> B[Precast Concrete Blocks]
    A --> C[Timber Lagging]
    B --> D[Calculate Volume (m³)]
    D --> E[Deduct from Concrete Lining Volume]
    C --> F[Calculate Volume (m³) as per IS 1200 Pt XXI]
    A --> G[Temporary/Permanent Supports]
    G --> H[Measure Weight (kg) including steel and lagging]

This ensures precise quantity estimation for project management and billing.

IS 1200 Part 25: Procedures for Measuring Rock Bolts and Steel Supports

Rock Bolts (Clauses 4.6 & 4.7)

• Measured by weight (kg) including:
  • Entire bolt body and threaded sections
  • Anchoring wedges or devices
  • Washers and nuts
  • Installation labor and charges
• Drilled holes for bolts are measured separately in running meters.

Steel Supports (Clauses 4.2 & 4.3)

• Measured by total weight (kg) encompassing:
  • Steel structural members
  • Lagging if present
  • Butt and feather plates
  • Bolts, nuts, tie rods
  • Temporary timber spreaders
  • Concrete pedestals
  • Backfilling with excavated material

Measurement Summary

Additional Notes

• Any enhancement of existing supports by adding members is measured separately.
• Weight-based measurement ensures accurate material and labor costing.

flowchart LR
    A[Rock Bolts] --> B[Measure Weight (kg)]
    B --> C[Includes bolts, wedges, nuts, washers]
    D[Drilled Holes] --> E[Measure Length (m)]
    F[Steel Supports] --> G[Measure Weight (kg)]
    G --> H[Includes steel sections, lagging, bolts, plates, tie rods]

This approach guarantees detailed and precise quantification of rock bolts and steel supports.

IS 1200 Part 25: Standard Units and Decimal Usage for Measurement

Measurement Accuracy (Clause 2.3):

• Linear dimensions are recorded to the nearest 0.01 meter.
• Surface areas are recorded to the nearest 0.01 square meter.
• Volumes are recorded to the nearest 0.01 cubic meter.
• Weights are recorded to the nearest 0.1 kilogram.

Special Cases (Clause 2.5):

• Special pumping is measured separately:
  • In kilolitres (kL) when electrical power is unavailable.
  • In kilowatt-hours (kWh) when using electric pumping.

Rounding Rules:

• Follow the rounding conventions of IS 2-1960.
• Maintain the number of significant figures as specified in this standard.

Summary Table of Units and Precision

Notes:

• Measurements are net values based on fixed-in-place items.
• Decimal and unit standards promote uniformity and clarity in civil engineering measurements.
• Precision supports accurate cost estimation and payment procedures.

flowchart TD
    A[Measurement Types] --> B[Linear Dimensions]
    A --> C[Surface Areas]
    A --> D[Volumes]
    A --> E[Weights]
    A --> F[Special Pumping]

    B --> |0.01 m precision| B1
    C --> |0.01 m² precision| C1
    D --> |0.01 m³ precision| D1
    E --> |0.1 kg precision| E1
    F --> |kL or kWh units| F1

This framework ensures consistent and accurate measurement practices for tunnelling and related civil works.

IS 1200 Part 25: Summary of Amendments and Revisions

• Clause 2.7 (Page 5): Entire clause has been deleted.

• Clause 3.1(b) (Page 5): Updated reference:

  • Previous: IS 1200 (Part 1) - 1974
  • Revised: IS 1200 (Part 1) : 1992
  • Footnote: Method of measurement of building and civil engineering works: Part 1 Earthwork (fourth revision).

• Clause 4.5 (Page 6): Reference updated from [see IS:1200(Part II)-1968+] to [see IS:1200(Part II)-1974+].

• Clause 5.1 (Page 7): Reference changed from [see also IS:1200 (Part II)-1968*] to [see also IS:1200(Part II)-1974*].

• Amendment No. 3 (April 1981): Applies to this part’s second revision for tunnel measurement.

Highlights:

• Updates mainly involve cross-references to newer editions of related IS parts.
• Footnotes clarify the latest versions applicable.
• No changes to core formulas or measurement tables, focusing on referencing updates.

For detailed measurement formulas or tables, refer to the updated IS 1200 Part 1 (1992) and Part II (1974).