Augering and Soil Types: Best Practices for High Voltage Tower Installations 


Augering, a critical process in the installation of high voltage transmission towers, involves drilling into the earth to create a foundation for these structures. The success of this process heavily depends on understanding and adapting to various soil types. Different soils present unique challenges and require specific techniques to ensure the stability and longevity of the transmission towers. 

Understanding soil types 

Soils are generally classified into several categories, such as clay, silt, sand, gravel and rock. Each type has distinct characteristics affecting its bearing capacity, moisture content and cohesiveness. For instance, clay soils, while stable, can expand or shrink significantly with moisture changes. Sandy soils, on the other hand, are more permeable but may lack the necessary cohesion. 

Best practices for different soils 

Clay and silt soils. In these soils, augering must be done carefully to avoid wall collapse during drilling. Using stabilising agents like bentonite can help maintain the integrity of the borehole. Additionally, immediate placement of the tower foundation following drilling is recommended to prevent soil collapse. 

Sandy and gravel soils. These soils require a different approach due to their loose nature. Using casing during the augering process can help support the walls of the borehole. It’s also crucial to minimise vibration during drilling to prevent soil around the borehole from collapsing. 

Rocky soils. Drilling in rocky terrain may require specialised augering equipment with enhanced cutting capabilities. It’s important to adjust the drilling speed and pressure to efficiently penetrate through rock without damaging the equipment. 

Site assessment and planning 

Conducting a thorough site assessment before beginning the augering process is essential. Soil testing, including analysing soil composition and moisture content, provides valuable information for selecting the appropriate augering technique and equipment. In addition, understanding the local geology helps anticipate potential challenges. 

Augering techniques and equipment 

Selecting the right augering equipment is crucial. For softer soils, augers with wider flights are effective, while for harder soils, a more robust, narrow-flighted auger is preferable. The choice of auger should also consider the depth and diameter required for the tower foundation. 

Environmental considerations 

Environmental impact should be considered, especially in sensitive ecosystems. Techniques that minimise soil disruption and protect the surrounding environment are vital. 

Applying best practices 

Successful augering for high voltage tower installations requires a comprehensive understanding of soil types and appropriate techniques. By employing best practices tailored to specific soil conditions and emphasizing thorough planning and environmental sensitivity, the foundation for transmission towers can be safely and effectively established. 

When it comes to foundation drilling, our role here at Tebco is to provide augers built to the highest engineering standards. We have three generations of experience and over the decades, we’ve helped contractors successfully complete their projects that require powerful drilling.