Fortunately, most people don't need to dig through frozen dirt; it is so solid that many experts actually compare it to concrete. If you think about it, though, the need to do this is genuine in some instances for things like digging down to frozen utility pipes and burying caskets. So, how do the professionals handle these kinds of jobs?
Tools for Digging Through Frozen Dirt
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The majority of ground freezing occurs close to the surface, forming a permafrost crust. Once you have pierced that permafrost layer, things get a lot easier. Professionals have specific tools that they use to pierce through and excavate frozen ground, including frost buckets. These are for commercial purposes, attaching to machines, such as cranes, before use. They are bucket-shaped and made with narrow points and sharp tines and can penetrate through the top layers of frozen dirt.
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Static rippers can also be used to dig up the frozen ground. These have a large, single "tooth" and attach onto machines as well. These produce high-frequency vibrations that go into the ground while the ripper gets pulled along, creating a more extended, narrower break than a frost bucket. Some of these more significant pieces of equipment can be hard on machinery because they have a weighty impact and use a lot of force.
Digging Through Permafrost
Hydrovac or daylighting is based on pumping hot water into the ground for suction removal and requires highly specialized equipment and team members. This particular method introduces many other concerns, though, such as a more complicated process for the proper disposal of the excavated materials and an introduction of possible water contamination. Rotary cutters have rows of turning blades and use hydraulic rotational force to chip through the solid frozen ground. These cutters can be effective, but they work very slowly.
Hydraulic hammers also use that kind of force but with a punching action that basically hammers holes into the frozen ground. These hydraulic hammers have additional bits that can pry up chunks and loosen the ground. The last choice and the one with the highest cost is using self-contained ground heating systems, which operate like giant industrial blankets that you place on the ground and use to heat the earth's surface.
Heating the Ground
Companies use those electrically heated blankets to thaw the stubborn ground. They are weathertight and usually have weights or grommets to allow them to be staked or tied down. These blankets can also have internal thermostats, and you can often add extra insulation to make them heat up faster. Cemeteries and landscapers use these kinds of products.
If you need to warm up ground on your property and don't want to invest in any of these tools, you can build a temporary shelter, like a giant tent, over the place where you need to dig. This tent can increase the ground temperature, and even a few degrees can help. Another choice is to build a charcoal fire over the area, but this can present a fire risk. Keep the fire on the smaller side and do not put it inside the shelter.
Many people also heat frozen ground with water, but you can't do this in a very large space. You'll need to boil enough to cover the area and saturate it. Boil a couple of gallons at a time and pour it over the ground over a time period of a few hours. When you see that it has softened, get a sharp shovel or a pick and try to break through the first layer. Once you break through this top layer, you should be able to finish the job.