When a pile won't drive properly, the root cause is almost always the soil. But it's important to understand that not every difficult section is created equal. Sometimes a pile gets stuck in a clay lens, while other times it literally hits a boulder. To figure this out, you need to understand what exactly is preventing it from driving. Here are the main types of problematic soils: · Stony or bouldery soil. Underground, there may be a block, a boulder, or simply a scattering of large crushed stone. A pile won't cut into such material—it either hits the ground or goes sideways. · Gravel with clay. This type of soil can "chew" the pile: at first, it goes forward, then suddenly slows down. It seems like it's stuck, but in reality, there's simply not enough torque. · Rocky soil. In this case, a screw pile physically can't drive. It's lik...