The trenching crew typically uses a wheel trencher or backhoe to dig the pipe trench. DOT requires the top of a pipeline to be buried a minimum of 30 inches below the ground surface. The pipeline must be buried even deeper at river and road crossings.
If the crew finds large quantities of solid rock during the trenching operation, it uses special equipment or explosives to remove the rock. The crew uses explosives carefully, in accordance with state and federal guidelines, to ensure a safe and controlled blast.
In cultivated areas, the topsoil over the trench is removed first and kept separate from the excavated subsoil, a process called topsoiling. As backfilling operations begin, the soil is returned to the trench in reverse order with the subsoil put back first, followed by the topsoil. This process ensures the topsoil is returned to its original position.
Other steps in the constructions process:
- Clearing and grading
- Stringing and Welding pipe segments together
- Depositing the pipeline and Backfilling
- Testing
- Restoration