The success of a construction project hinges on the successful collaboration between many people with varied technical backgrounds and areas of expertise—from general contractors and subcontractors, to civil, structural, and geotechnical engineers.

While these professions share a broad vernacular—shaped by experience, tools, and real-world challenges—each also has its own technical language, including terminology that often can’t be found in a textbook.

Not speaking each other’s language can create confusion and frustration, and since time can be in short supply on fast-moving construction sites, the information below will give you a head start on learning a set of terms and acronyms relating to site work, soil types, and classification.

Geotechnical and Soil Mechanics Terms

When dealing with the complexities of modern construction, it’s critical to understand the types of soils that are present on a project, as well as the status of potential conditions affecting site work, pavements, working surfaces, and other geotechnical factors.

Here are some frequently used terms related to this work:

• Expansive soils (shrink swell clays): 
  Clayey soils that are highly sensitive to moisture content, expanding when wet and shrinking when dry, due to water absorption. 
  
  
• Fat clays: 
  Cohesive soils that are highly plastic and absorb a lot of water, becoming sticky or otherwise difficult to work with when damp. 
  
  
• Organic soils: 
  Soils rich in decomposed plants and animal matter (organic matter), typically dark in color and formed in wet conditions. They are usually weak in strength and highly variable. Construction over these types of soil usually results in non-uniform consolidation under load. 
  
  
• Sugar sand: 
  Sugar sand is an extremely fine, pale-colored soil, often found in regions like the New Jersey Pine Barrens. It’s known for being nutrient-poor, highly porous, and prone to rapid drying due to its high silica content. Sugar sand is difficult to cultivate, and, due to its fine, loose nature, acts as a poor base for construction, is unstable for building, and often requires deep foundations, and soil stabilization or removal. 
  
  
• Moisture content: 
  Soils are made up of solid particles, and voids between the particles that may hold air or water. The moisture content of a soil is a standard measure of how wet the soil is, based on how much water is present in the voids relative to the amount of solids in the soil.

Want to learn more?

We cover more geotechnical terms and abbreviations in our Beneath the Build series on YouTube! Click here to the first episode and learn more.