Monday, April 15, 2013

Curiosity in Everett

I confess I was feeling some self-pride on a project last week. Before contracting out a back hoe or drill rig I took a crack at hand drilling to investigate soil conditions at depth. The basis of the approach was from previous work I had done in this particular part of Everett which suggested that the glacial till that is mapped as underlying the area was thin or might be missing and the unit below is a very well sorted sand that could readily been hand drilled. 

I started with a sharp shovel and very soon encountered very hard tan glacial till. But I had faith in my theory so I pounded and chipped at the till and 18 inches down broke through to a very well sorted sand (well sorted in geology jargon meaning uniform in size and poorly graded in geotech jargon meaning all the sand was the same size).

Once into the sand I started with a wide auger to 5 feet and then switched to a narrow auger with extension rods. Made 14 feet in two holes and got stopped by a rock at 9 feet in a third hole.

So self pride in my geology interpretation, saving my client some money and the satisfaction of hand drilling a few deep holes. Alternatively, it could be that I never really progressed much beyond enjoying playing in the sand box. But then I drilled a lot deeper than Curiosity.

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