In the US, by law, you must call Digline before beginning any digging project. Call 811 to contact a local call center. The service is completely free to use.
Trees, shrubs and other plants may suffer injury or die if their roots are damaged in excavation. Driveways, sidewalks, and structures can collapse if they are undermined. Small plants, even turf grasses, can be removed and stored for replanting with proper care.
Some plumbing systems are gravity operated, and require a slope so the waste or water will flow unaided to the discharge location. In this situation, you may find the trench will be deeper on one end than the other.
Shoring: This process uses a support structure for your ditch sides so they do not cave in and injure anyone, or undo the digging you have done before the project is complete. For example, a small excavation could use sheets of plywood supported by posts. Large excavations could use steel trench boxes or sheet piling. Anything deeper than 3 feet (0. 91 m) should be shored up. Never enter a trench deeper than your waist if it is not shored up. De-watering: This removes the excess water from the soil to help stabilize it while working. This can be accomplished either with a well point system, or a sock pipe and mud-hog type diaphragm pump to remove the water as it seeps into the excavation. Benching the excavation: If you are digging in loose soil, a deep vertical trench wall is at risk of collapse. Benching involves digging the trench in steps or tiers instead, so the banks do not have to support more material than they are capable of. These benches are usually at intervals 2. 5–3 feet (0. 76–0. 91 m) deep and twice as wide. They do take quite a bit of sidewall digging, which can require extensive area to complete. Keep in mind that it can still collapse the deeper the trench goes.
Unless you are already experienced with these types of equipment, it may be cheaper and safer in the long run to hire a professional excavator.
If the topsoil is going to be stored for prolonged periods of time, over-seed with non-invasive grass species to reduce erosion, or cover it with a heavy tarp or plastic sheet. You may be charged fines if heavy soil or muddy water runs off your work site. Installing erosion control wattles or rolls can contain the water and prevent fines. These can be purchased at landscape and\or construction supply outlets.
If you need to bench, make subsequent entrenchments to the depth of each bench prior to digging deeper, so the banks of each bench will remain stable throughout the process.
It is very difficult to ‘walk’ a piece of equipment back down an excavated trench. The heavy weight of the tools or machinery can increase the risk of collapsing trench walls. If you are operating equipment on your own, always keep it on undisturbed solid ground for as much of the process as possible.
