From the Ground Up: Earthworks Part I
Preparing the Ground: Before a structure stands tall, the soil beneath it must stand firm.
Once the subsurface evaluation and design work are complete and the site has been stripped, cleared, and graded, the next step is assessing the exposed subgrade. This is where we begin confirming that the ground can safely support the structure to come at all locations between the test borings made for the subsurface evaluation.
What Happens During Earthworks
Our inspectors begin by evaluating the natural ground at the site — known as the subgrade — to understand its strength, moisture, and overall stability. This initial assessment sets the stage for every decision that comes next.
One of the first tools we use is proof rolling. A fully loaded dump truck or similar heavy vehicle drives across the prepared surface while we observe how the soil responds. If the tires leave deep ruts, the surface pumps or shifts under the weight, or the soil visibly moves, it’s a clear sign the subgrade isn’t strong or dry enough yet.
These weak spots can develop from saturated clay, disturbed soil, trapped water, or pockets of previously placed fill that were never properly compacted. When we find them, our team digs shallow test pits — small openings that let us see how deep the issue goes and what’s causing it.
Preparing the Site for Foundations
With that information, our engineers determine what the site needs to become build-ready: allowing the soil to dry, strengthening it with lime, cement or geotextiles/geogrids, or removing and replacing material that can’t support future loads. Only once the ground is stable do crews begin adding fill — compacted soil placed in layers to create a strong base for the structure above.
Testing the ground is the first and most important step because it determines everything that comes next. A strong building starts with soil that stands firm.
Come Build on Our Foundation
From the Ground Up is a series exploring the engineering and materials testing processes that support safe construction across Central Virginia.
Explore more in the series