1. General Description
This specification outlines the requirements for quarrying, transporting, and spreading selected materials from designated borrow areas to construct embankments. The work includes placing materials in uniform layers not exceeding 23 centimeters in thickness, dressing, breaking clods, compacting at the required moisture content to achieve the specified dry density using appropriate rollers, and watering at Optimum Moisture Content (OMC). The scope covers all operations within a lead distance of up to 1.0 kilometer and includes all necessary lifts and dewatering to ensure the stability and integrity of the embankment.
2. Materials
- Borrow Material: The selected material shall be sourced from approved borrow areas and shall conform to the project specifications for embankment construction. The material shall be free from organic matter, deleterious substances, and shall possess suitable gradation to achieve the required compaction and stability.
3. Equipment
Excavation Equipment: Appropriate machinery such as excavators, loaders, and bulldozers shall be used for quarrying and loading materials from the borrow areas.
Transportation Equipment: Trucks or hauling units capable of efficiently transporting materials within the specified lead distance of 1.0 kilometer shall be utilized.
Compaction Equipment: Rollers suitable for achieving the desired compaction, such as vibratory, pneumatic-tired, or static weight rollers, shall be employed. The type of roller used shall be appropriate for the material type and site conditions.
Watering Equipment: Water tankers equipped with spray bars to uniformly distribute water for moisture conditioning of the embankment material.
4. Construction Methods
Site Preparation: Before commencing embankment construction, clear the site of all vegetation, debris, and unsuitable materials. The foundation surface shall be scarified to a depth of not less than 100 millimeters to ensure proper bonding between the existing ground and the new embankment material.
Material Excavation and Transportation: Excavate the approved borrow material and transport it to the embankment site within the specified lead distance. Ensure that the hauling routes are maintained to prevent spillage and contamination of materials.
Spreading and Layering: Deposit the material in uniform layers not exceeding 230 millimeters in loose thickness. Each layer shall be spread evenly and dressed to the required profile before compaction.
Moisture Conditioning: Adjust the moisture content of the material to within ±2% of the Optimum Moisture Content (OMC) as determined by standard Proctor compaction tests. Uniformly apply water using the watering equipment and mix thoroughly to achieve consistent moisture distribution.
Compaction: Compact each layer to achieve a minimum of 95% of the maximum dry density as per AASHTO T 99 (Standard Proctor). The compaction process shall be continuous until the desired density is attained, with particular attention to edges and corners to ensure uniform compaction throughout.
Dewatering: Implement necessary dewatering measures to maintain dry conditions during construction. This may include the use of pumps, drainage channels, or other appropriate methods to remove surface and subsurface water.
Quality Control: Conduct field density tests on each compacted layer to verify compliance with the specified compaction requirements. Testing frequency and locations shall be as directed by the Engineer.
5. Measurement and Payment
Measurement: The quantity of embankment material shall be measured in cubic meters, based on the compacted volume in place. Measurements shall account for the dimensions shown on the project drawings or as directed by the Engineer.
Payment: Payment for embankment construction shall be made at the contract unit price per cubic meter, which shall include compensation for quarrying, transporting, spreading, moisture conditioning, compaction, dewatering, and all other incidental work necessary to complete the item as specified.
6. Safety and Environmental Considerations
Safety: All operations shall comply with applicable safety regulations. Personnel shall be equipped with appropriate personal protective equipment (PPE), and machinery shall be operated by qualified individuals.
Environmental Protection: Take necessary precautions to minimize environmental impact, including dust control measures during transportation and compaction, proper management of water discharge from dewatering operations, and restoration of borrow areas in accordance with environmental guidelines.
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