Monday, August 4, 2014
Core Drilling - Building the Winery: Part 2
So following this we needed the input of a GeoEngineer (a combined soils engineer and geologist) to determine whether all of our plans could be implemented and how far towards China we have to sink our footings in before we actually start pouring the slab and putting up framing. That's where the core drilling comes in.
The process is really quite simple to understand. Stratums are determined using a split-spoon sampling method which pulls up soil from varying depths and defines its composition. Going down 20', we had three stratums identified. For our first 5' we had silty & clayey sand. From 5' deep to 14' this soil changed over to a well-graded sand, and from about 13' deep to 20' down we had a lean clay composed of a lot of shell fragments. Since our farmlands were well under water thousands upon thousands of years ago, this was no surprise. Then there were the "blow tests", where a 140 pound hammer is allowed to fall 30". Counting the number of hits it takes to go 12" provides an "N"-value. In our 1st stratum it was 9, in our 2nd stratum it increased to 14, and then in our lowest / 3rd stratum it was reduced to 6 (we found mush). Using these two bits of information it allowed the GeoEngineer to define relative density and soil consistency, which then led to the engineering recommendations regarding construction footings. Simple, huh ?
There are a few other tests done too. Like putting the sand through a sieve to determine granular size, and by doing various moisture tests that allows one to conclude how compaction of the soil will be influenced by the weight of the structure.
We are still waiting for our septic system design, so once we get it we can apply for our building permit !