The Mysterious "Cemented" Soil

I well remember the day when I had the opportunity to visit with Dr. Jack Mickle and ask questions that had been bothering me. One question I had was about cemented soils. Specifically, the definition of cemented soils in Appendix A of Subpart P seemed to describe caliche but not hardpan, although both are mentioned in the standard.

He agreed, but he encouraged me to keep it simple. “If a hand-size sample cannot be crushed into powder or individual soil particles by finger pressure, we can call it “cemented”, regardless of whether it is caliche or hardpan.”

He explained how each of those cemented soils can be formed, but the take-away for me was to keep it simple. I believe keeping it simple is the key to understanding soil classification in general and specifically when conducting tests to determine the composition of the soil. After all, a few pages in Appendix A is not a course in geology, but a way for the competent person to get a field estimate of the soil’s stability. The point of which is to ensure we have an adequate protective system.