Day 4: Pounding sand...again

A short post today - more of the same as yesterday. The 3 foot deep hole was filled with about 1 foot of soil at a time. Each of these fills is called a lift. The foot of soil was compacted a few inches, then another lift was applied and compacted. The geotech engineer showed up for another moisture-density test after approximately 2 feet of lifts.

We passed the test and started filling up the remainder of the hole and leveling out the entire subgrade. Here is a vid of me driving the compactor (maximum speed, 50 feet per minute :-)

At the end of the day, the full subgrade for the concrete slab is really beginning to take shape. Here's a pic from where the West entry will be.

Thanks for reading. Feel free to post a comment.

Day 3: Pounding sand...in a good way

If pictures tell a thousand words each, then videos should be even more.

The day began with cleaning out the Western 3 foot deep section of subgrade. Here is a vid of a tree root being removed.

After flattening the 3' deep section, a sheepsfoot compactor is used to, duh, compact the soil. It has a vibrating sand filled steel drum for a front tire. It is driven back and forth over the soil many times like in the following vid.

The goal is to get the soil to 90% of its maximum possible density and as close to optimum moisture content as possible. The geotechnical engineer took a soil sample yesterday to determine the density versus moisture curve for my site soil. Look here for an example curve. We called in the the geotechnical engineer again today to see if the soil was dense enough. He used a machine called a Nuclear Surface Moisture-Density Gauge. First he pounds a pin into the soil at least 6". He then inserts the probe of the gauge into the hole and pushes a button. The results are compared to the lab sample curve in seconds. We passed! The soil is nearly the density of concrete. Here's a vid of those last few steps. Sorry it's 90 degrees off. My old camera doesn't adjust when I rotate it, so you'll have to turn your head.

Finally, I leave you with a picture of Gabby (Steve's dog), the grading mascot.

A good day today. Thanks for reading. Don't be shy, leave a comment.