Excavation in Road Construction: Methods and Steps

Excavation in Road Construction: Methods and Steps

Excavation is critical in any construction project that involves removing dirt, rocks, and any unwanted materials from a site in order to build a strong foundation for a structure.

When it comes to road construction, good excavation work is the first step to a strong and stable subgrade, thus demanding execution with precision using the right equipment and skilled workers.

This blog explores the purposes, methods, and steps before starting excavation in a road construction project. 

Importance of Excavation in Road Construction

Excavation is a vital part of the road construction process for several reasons:

Site Preparation: 

The construction site ground should be cleared of obstacles and levelled. Excavation helps to eliminate bushes, rocks, debris, and other impediments and level the construction site. This ensures that the foundation and other structural components are erected on stable ground.

         Subgrade Preparation: 

The base of your pavement is extremely important in determining how long it will last and how well it will withstand the traffic load for its expected lifetime. When it comes to road construction, making subgrade preparations and installation is one of the most important steps of your pavement project.

Drainage and Erosion Control: 

Effective excavation aids in the design and implementation of effective drainage systems, reducing the possibility of water deposits and erosion near the construction site. This is crucial in regions that frequently experience heavy rain or flooding.

Access and Transportation: 

During the construction process, excavation can be used to build access roads, paths, or ramps for the transportation of goods, equipment, and workers. This improves the project’s efficiency and helps keep workers safe while they are working on the site.

Methods of Excavation Applied in Road Construction

Topsoil Excavation

This type of excavation is performed for the removal of the exposed or uppermost section of the earth’s surface. This excavation procedure eliminates bushes, soil, and any other decaying objects so that the site becomes ideal for supporting construction loads.

Rock Excavation 

This excavation method is used to remove rocks from the rocky soil to prepare the sites for road construction, as rocky surfaces obstruct the construction process. In comparison to the other varieties, rock excavation is challenging and requires specialised equipment and procedures, such as drilling or blasting to remove the rock or clear a difficult surface.

Muck Excavation

Muck, a mixture of earth and water, is mostly undesirable during construction and must be removed. Muck excavation is named after the material that is being extracted. The muck is either transferred to a different location or spread out to dry.

Earth Excavation

Earth excavation involves excavating the soil below the topline to the required depth to prepare a subgrade of the required density by compaction. 

Cut and Fill Excavation

This type of excavation in construction, also known as stripping excavation, is used to clear large areas. The procedure includes removing wide and shallow layers of topsoil, rocks, sand, and other undesirable objects. Land grading may also be a part of this process.

Steps to be completed before starting excavation in road construction 

Site Surveying 

Site surveying is done to create a topographic map of the land and helps provide the following vital information: 

  • Elevations and notable features of the land, such as trees, hedges, fences, sewage access, manholes, etc. 
  • Land size and shape, and the contours of valleys, slopes, gorges, etc. 
  • Right-of-way and easement locations
  • All features important to the landowner’s measurements and distances from his boundary, such as houses, sheds, fences, utilities, etc.
  • Defines the boundaries of the land by indicating the location and description of objects or markers.

Soil Testing 

Before constructing a road, soil testing is required to identify the composition and features of the soil at the construction site. This information is necessary for designing and building a road that is secure and solid enough to bear the weight and movement of vehicles.

Testing the soil is also required to identify any potential difficulties, such as soft spots or spots with significant erosion, that may need to be addressed prior to the start of construction. Additionally, testing can help determine the best building practices and materials to use, ensuring that the road is reliable and durable.

Geotechnical Analysis of the Land

Analysing the geological composition and groundwater conditions of the location is another extremely important type of soil research performed by geotechnical engineers or engineering geologists. 

Groundwater and its level have a significant impact on the foundation soil’s carrying capability. Soil mechanics state that as the groundwater level declines, the pore water pressure in the foundation soil drops and the effective stress rises, causing the foundation to settle.

Geotechnical studies evaluate groundwater levels to determine the best strategies for ensuring damage-free construction. There are maps that illustrate the water table height and sites that may be vulnerable owing to shallow groundwater pooling. 

If you are building a road in an area where the water table is high enough to block your excavation, you must install a temporary pump and dig a trench to channel the water away from the excavation site. This could be a challenging task for novice excavators.

Get the Right Tools and Instruments

Contrary to popular belief, excavation requires skill and patience. If you want your excavation to be exact, you should work with an experienced and licensed company like Fluid Construction, which employs the proper tools for a range of excavation needs. This not only contributes to a neat and tidy product but also to the timely completion of the task.

Some Common Types of Excavation Equipment

  • Shovel
  • Spade
  • Hoe
  • Pick axe
  • Rake
  • Backhoe loader
  • Bulldozer
  • Crawler loader
  • Spider excavator
  • Swamp excavator
  • Zero-swing excavators
  • Trencher
  • Skid-steer loader

Another very important area where people tend to cut corners is in safety precautions. This is very risky and may cause disruption to the project because an excavation site is prone to a variety of accidents and material loss possibilities, such as:

  • Sudden cave-in of the area of excavation.
  • Falling of people or animals in the pit
  • Equipment damage or destruction

Many of the potentially dangerous incidents that can occur at excavation sites can be avoided by ensuring that the excavation area is blocked off from the access of unauthorised people, workers have put on safety gear, and proper instruments have been used. 

Excavation is the vital initial step that creates the foundation for a network of roads that is secure, sturdy, and long-lasting. The various techniques, which range from mechanical excavation to physical labour and blasting, all aim to provide a stable foundation.Are you interested in learning more about road construction? Keep exploring our blogs for more information on the intriguing world of infrastructure and building. Remember, the road to knowledge is always under construction. Stay curious!