In last month’sNational Driller, I started a discussion of limited access drilling with some thoughts on site visits, and the challenges presented by the power, torque and pullback of rigs designed to work in smaller spaces. This month, we hit the job site with a look at geotechnical and environmental field work. <br><br>
You’re a home owner, and you want to build an addition on the back of your house. You need a geotechnical investigation done to determine the design of your foundation and footings. What do you do? You can’t get a CME 75 in your backyard, and even a 45 won’t make it through the gate, and then across the nice wooden deck surrounding your pool and up a few steps to your interlocking brick patio. Drilling the holes in front of the house is pointless. The engineers need to get their samples and blow counts from within the footprint of the new addition. Most engineering companies know at least one drilling company that has a small rig for such a situation. Sometimes that “rig” is a couple guys with strong backs, a 70-pound chunk of steel, some rods and a split spoon. Other times, it’s a tripod design, a small portable auger rig on wheels that’s hauled around by hand, or in a more ideal situation it’s a small track-mounted rig that’s narrow enough and nimble enough to maneuver through the gate, and around a corner past the gardens, and powerful enough to make your day easier. Like any other geotechnical project, you still drill to the specified depth, drop your hammer and continue on to the next interval, until the hole is completed and you can move on to the next one or you’re finished for the day.