IS 1200: Part I – Earthwork
IS 1200 Part I deals with the methods of measurement of earthwork in civil engineering projects. Below is a detailed summary of this part, covering scope, definitions, general rules, and measurement methods.
1. Scope
This part of IS 1200 specifies the methods for measuring earthwork, including excavation, filling, and embankments, for various civil engineering purposes. It applies to the following types of work:
- Excavation for foundations, trenches, and basements.
- Filling for embankments, backfills, and site leveling.
- Earthwork in roads, railways, canals, and other infrastructure projects.
2. Definitions
Key definitions relevant to earthwork measurement:
- Excavation: The process of removing soil, rock, or other materials from their natural location.
- Filling: The process of placing soil, rock, or other materials to form a desired shape or level.
- Embankment: A constructed mound of earth or stone to carry a roadway, railway, or canal.
- Bulk Excavation: Large-scale excavation work, typically for site preparation.
3. General Rules
- Units of Measurement: Earthwork is measured in cubic meters (m³).
- Levels and Dimensions: Measurements should be taken from established levels and dimensions specified in the project plans.
- Deductions: Deductions are made for voids, bulking, and shrinkage based on specified guidelines.
- Recording: All measurements should be recorded to the nearest 0.01 cubic meters (m³).
4. Methods of Measurement
Excavation
- Classification of Excavated Material:
- Ordinary Soil: Loose or soft soil that can be excavated manually or with light machinery.
- Hard Soil: Dense soil requiring mechanical tools for excavation.
- Rock: Material requiring blasting or specialized equipment for excavation.
- Measurement Principles:
- Volume Calculation: Volume is calculated by measuring the difference between original ground level and the final level after excavation.
- Trenches and Foundations: For regular shapes, volume (V) is calculated using the formula:
[
V = L \times B \times D
]
where ( L ) is the length, ( B ) is the breadth, and ( D ) is the depth.
- Formulas:
- Trapezoidal Rule: For irregular sections, the volume can be estimated using:
[
V = \frac{h}{2} \left[ (A_1 + A_n) + 2 \sum_{i=2}^{n-1} A_i \right]
]
where ( h ) is the interval between sections and ( A ) are the cross-sectional areas.
Filling
- Material Classification:
- Earth: Natural soil used for filling.
- Sand/Gravel: Used for specific types of filling, especially where drainage or stability is required.
- Measurement Principles:
- Volume is measured in cubic meters (m³).
- For embankments, the volume is calculated by cross-sectional area method along the length of the embankment.
- Formulas:
- Volume Calculation for Embankments:
[
V = \frac{1}{2} (B_1 + B_2) \times H \times L
]
where ( B_1 ) and ( B_2 ) are the top and bottom widths, ( H ) is the height, and ( L ) is the length.
Embankment
- Classification:
- Embankments are typically constructed for infrastructure projects like roads, railways, and canals.
- Materials include soil, sand, gravel, and sometimes rocks.
- Measurement Principles:
- Volume is measured in cubic meters (m³).
- The cross-sectional area method is used for calculating volumes along the length of the embankment.
5. Deduction for Voids and Bulking
- Voids: Deductions are made for voids within rock or other materials where applicable.
- Bulking: A bulking factor is applied to account for the increase in volume when soil is excavated and becomes loose.
6. Payment and Billing
- Payment is based on the net volume of work measured.
- Rates include all costs associated with materials, labor, equipment, and any incidental charges.
- Specific provisions are made for handling difficult conditions, such as working in waterlogged areas or handling hazardous materials.
Example Calculations
Excavation Example
For a trench of length 10 meters, width 2 meters, and depth 1.5 meters:
[
V = L \times B \times D = 10 \times 2 \times 1.5 = 30 \, \text{m}^3
]
Embankment Example
For an embankment with a bottom width of 5 meters, top width of 3 meters, height of 2 meters, and length of 100 meters:
[
V = \frac{1}{2} (B_1 + B_2) \times H \times L = \frac{1}{2} (5 + 3) \times 2 \times 100 = 800 \, \text{m}^3
]
Conclusion
IS 1200 Part I ensures standardized methods for measuring earthwork, providing clarity and consistency in the estimation and billing processes for civil engineering projects. Accurate measurement practices are essential for project planning, cost estimation, and ensuring fair payment for work completed.
