Work Procedure of Excavation at Construction Site

Excavation Process in Construction

Excavation is a crucial phase in construction, involving the movement of earth, rock, or other materials using tools, equipment, or explosives. It includes trenching, wall shafts, tunneling, and other underground activities, serving as the foundational activity for any construction project. Understanding excavation entails knowledge of drawings, setting out plans, soil management, and quality assurance checks to ensure precision and adherence to project specifications.

Drawings Required for Excavation

1. Centerline Drawing or Gridline Drawing

• Description: These drawings show grids marked with numbers and alphabets, which help in site marking for reference. Grid lines align with excavation and footing areas.

1. Excavation Drawing

• Description: This drawing specifies the dimensions (length, width, and depth) of the excavation, usually represented by a dotted line.

Scope of Work for Excavation

The scope of work in excavation includes several key tasks conducted before, during, and after the excavation process:

• Setting out corner benchmarks
• Surveying ground levels and top levels
• Excavating to approved depths
• Dressing loose soil and ensuring compliance with cut-off levels
• Constructing dewatering wells and interconnecting trenches
• Marking building boundaries and constructing protective bunds and drains

Working Procedure of Excavation

The excavation process involves the following steps:

1. Clearing and Site Preparation

• Description: Clear the site of unwanted vegetation, bushes, and debris.

1. Setting Out

• Description: Mark excavation lines and centerlines on the ground. Establish corner benchmarks on permanent structures to guide level measurements.

1. Depth Fixing and Excavation

• Description: Determine and execute excavation depth using reference drawings and benchmarks, manually or with machinery, based on availability.

1. Soil Management

• Description: Remove excavated soil from the site or stock it nearby, keeping a minimum distance of 1 meter from the excavation pit to prevent soil erosion.

1. Pit Dressing and Safety Measures

• Description: Dress excavated pits as per drawing specifications. Implement proper shoring in loose soil areas for safety and seal all sides of the building.

Removal of Excess Soil

Efficient management of excavated materials is vital for project efficiency:

• Reuse of Excavated Material: Use for backfilling, gardening, or road preparation.
• Simultaneous Excavation and Filling: Carry out both to minimize handling.
• Stacking and Disposal: Stack excess material appropriately to prevent obstruction of other activities and promptly dispose of unwanted material.

Quality Checks for Excavation

Quality assurance measures are integral to ensure the excavation process adheres to project specifications:

1. Initial Ground Levels and Pit Dimensions

• Record initial ground levels and verify pit dimensions.

1. Material Management

• Dispose of unsuitable material and stack suitable material for backfilling.

1. Approval for Strata Classification

• Obtain approval from competent authorities.

1. Compliance with Drawing Specifications

• Ensure pit bottom and side dressing comply with drawing specifications.

1. Safety Measures

• Implement necessary safety measures throughout the excavation and filling procedures.

By meticulously following these procedures and quality checks, excavation activities can be conducted efficiently, laying a strong foundation for successful construction projects.