Which statement best describes trench bottom compaction in relation to pipe support?

• A. Providing additional drainage
• B. Providing continuous firm support
• C. Allowing expansion under load
• D. Reducing backfill time

Answer: (B)

Providing continuous firm support under the pipe is essential because it creates a solid, uniform base along the entire bottom of the trench. This prevents differential settlement and pipe deformation as loads from the backfill and service pressures are applied, helping to maintain proper alignment and joint integrity over time. Drainage is a separate consideration in trench design, expansion under load is undesirable when the bottom is properly compacted (a firm base resists unwanted movement), and backfill time isn’t the primary function of bottom compaction.