NGA 71 Operator Excavating And Backfilling In The Vicinity Of A Pipeline (Critical AOC) Practice Test

Using shoring or trench boxes is the reliable way to keep a ditch from caving in. These protective systems are designed to hold up the trench walls, transferring earth pressures to a structure that resists collapse. They create a stable, safe workspace even in unstable or saturated soils, which is especially important when working near pipelines where movement or loads could endanger the line. Protective systems are chosen based on soil type and trench depth and must be installed by trained workers under a competent-person plan. This approach directly addresses the force that causes cave-ins, making it the best method. Deepening the trench tends to increase the risk of a collapse by adding more unsupported wall area. Tape offers no structural support, and trying to reduce soil moisture isn’t a reliable or sufficient way to prevent a cave-in.