This is Ding Dong, foothills for the Texas Hill Country. That means ‘rock’ and a lot of it. Normally, you would be able to sink the support posts using an 8 pound sledge, but not here. To the rescue, on Bosch hammer drill with a 33″ 1 1/8 drill bit supplemented by a 15″ 1 1/2 drill bit.
Using the hammer drill, we were able to drill thru much of the limestone or at least shatter it enough to get the pipes in the ground. When it got really rough we would put the 1 1/2″ bit on to increase the diameter of the hole. We put water down the holes to help make the caliche gummy while be hammered in the poles.
You can see the limestone coming from the hole.
We would fill the hole with water, ream out the excess mixture, add more water, then set the pipe.
There are advantages and disadvantages to height!