Sub-Surface Geophysical Sampling - Preparation and Execution
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Residential Sub-Surface Exploration
We have two coring rigs, a big one that goes up to 10" and a smaller one with a 5" capacity. This is the larger one. They both hold themselves in place by pulling a vacuum under the base.
The diamond coring rigs require a water connection to operate. In the house we used a hand-pumped supply (the red can) instead of a hose to a faucet.
Hole #3 was in the bathroom closet and was a tight fit for the tool and operators.
Julie Lindstrom (Foreground) and Jody Hasman coring hole #3.
The core bits rotate at a very high RPM and they are cooled and lubricated by water pumped into the bit. This usually results in slop being strewn about the work area. We 3D printed custom mud shields that were attached to a shop vac. They worked great.
Library Built-Ins are prepped. The gap between the baseboard and floor is visible to the left of the display cabinet.
The Library floor has been removed and Hole #4 is ready to set up. The orange and black reel is our GenEye II video snake and is being used to trace the heating ducts embedded in the slab so that we don't accidently core into one of them.
The Library Tongue and Groove flooring has been removed the entire width of the room.
Hole #8 in the Family Room is the control point because this slab section has not moved. Samples from other holes will be compared against the sample from this hole in the lab. (From L to R) Julie Lindstrom, Jody Hasman, Holly Holzhauer.
The sample will be taken by driving a 2" diameter by 48" long hollow tube down into the dirt below the slab as far as it can be driven. Some component parts of the sampling rig are shown to the left.
The sampling rig is assembled over Hole #8 and is ready to go. In operation, a sliding weight (the 'hammer') is lifted by hand to the top collar and released. The weight then travels down the guide rod and strikes the collar at the bottom (where the wight is now) which drives the coring tube into the earth. The coring tube is hollow and when the sample is complete, the tube is pulled out of the hole with a jack, but the 'core' of dirt stays in the tube. The boring tube is then removed from the rest of the apparatus and the core of dirt is pushed back out of the hollow tube for lab analysis. Voila' you now have a physical profile of the dirt as layered to a depth of 48"!
Solar Testing Laboratories' Mike Russo PE and Brian are sampling Hole #8. MIke has just released the hammer and Brian is observing and recording how far the coring tube is being driven by each hit (an important metric). Consistent technique with the release of the hammer is important too.
Setting up for Hole #6 in the foyer. (L to R) Jody Hasman, Tom Hall, Andrew Tucholsky, Holly Holzhauer.