Module 2: Setting Out and Excavation 

1. Site Layout and Marking

Reading Construction Drawings

• Blueprint Interpretation: Understanding foundation plans, elevation drawings, and utility layouts.

• Key Elements: Identifying boundaries, excavation depths, and structural positions.

• Scaling & Dimensions: Using measured scales (1:50, 1:100) to transfer plans to the actual site.

Using Levels, Pegs, and String Lines

• Levels (Laser/Spirit Levels): Ensures flat and even surfaces before excavation.

• Peg Markers: Wooden or metal pegs mark trench boundaries, corners, and levels.

• String Lines: Guides straight excavation lines and helps maintain correct depth and alignment.

2. Excavation Techniques

Manual vs. Mechanical Excavation

Trenching and Bulk Excavation

• Trenching: Narrow, deep digs for pipelines, cables, or footings.

• Must follow safe depth-to-width ratios to prevent collapse.

• Bulk Excavation: Large-scale digging for basements, foundations, or land leveling.

• Requires dump trucks and bulldozers for soil removal.

3. Soil Types and Stability

Identifying Soil Conditions

Risks of Collapse and Prevention

• Causes of Collapse:

• Loose soil (sand/gravel).

• Water saturation (weakens trenches).

• Vibrations (near heavy machinery).

• Prevention Methods:

• Shoring: Installing metal or wooden supports inside trenches.

• Battering (Sloping): Cutting trench walls at an angle to reduce pressure.

• Trench Boxes: Protective shields for workers inside deep trenches.

• Regular Inspections: Checking for cracks or soil movement.

Conclusion

This module covers accurate site marking, efficient excavation methods, and soil safety measures—key for preventing costly errors and accidents. The next module will focus on drainage and utilities installation.