Which practice must be avoided during the backfill process?

During the backfill process, compacting too quickly is a practice that should be avoided because it can lead to several problems, including inadequate compaction and soil instability. If the soil is compacted too rapidly, it may not allow for proper settling and distribution of forces, which can result in voids or weak spots in the backfill material. This can subsequently lead to issues such as sinkholes, settling of the tank, or even damage to the UST system itself. Proper compaction requires a controlled approach, allowing the material to settle and achieve appropriate density without excessive force that can compromise the structure's integrity.

While the other practices listed might also pose risks during backfill operations, fast compaction specifically compromises the stability of the backfill and the safety of the storage tank installation.