We follow ASTM D2488 for soil description and ASTM D420 for subsurface exploration. In Austin, the variability between the Taylor Formation clays and the Colorado River alluvium makes direct visual inspection essential. An exploratory test pit lets us see the actual soil profile, photograph it, and log it on site. This beats relying solely on borehole logs when you need to verify shallow bedrock depth or check for undocumented fill. We dig to safe depths, typically 10 to 15 feet, and log every layer. Before placing footings or running utilities, this method gives you the clearest picture of what lies beneath.
Seeing the soil in place — its color, structure, and moisture — tells you more about its behavior than any lab test alone.