[WARNING – DIRT NERD CONTENT]
Do you realize how many different ways there are to measure soil for an excavation and earthwork project?
All of them are very useful to understand! We’re going to break them down for you and discuss how each one can be used, and how you can convert between different measurements!
First, there are three primary categories to measure dirt in an excavation or earthwork project: weight, volume, and density. We’ll discuss nuances to each below.
For the first in this series, we’ll discuss the volume of material, the most commonly used unit of measure. Most earthwork projects measure in cubic yards. (1 CY = 27 cubic feet). Cubic yards are typically just called CY, but did you know there’s also LCY, BCY, and ECY? The problem with measuring dirt in cubic yards if that when you pull dirt out of a hole and load it in a truck, it fluffs up, creates air voids between the particles, and loses density. This dirt is now roughly 10%-20% more volume than it was when it was in the earth. The technical term for this phenomenon is swell: when you convert from BCY (bank yards) to LCY (loose yards).
When that truck then dumps out that dirt, a dozer knocks it down, and a vibratory roller comes by and beats the heck out of it that dirt becomes dense, embanked CY (ECY). Depending on compaction specifications and existing conditions, that dirt can be anywhere from 0%-10% less volume than when it was in the hole to begin with! This is called shrink, when soil loses volume.
You could see how people can easily disagree on quantities on pay applications.
If you’re counting loaded trucks, you might think you’ve moved 100 CY when you’ve only excavated 80 CY!
It’s important when discussing measurement and payment that everyone is on the same page so that disagreements are to a minimum and project operate as a smooth team. So if you’re looking for an excavation contractor in Colorado Springs that understands soil, we know your dirt.
Stay tuned for the next posts discussing how to know for sure exactly how much shrink and swell you’re getting!
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