(2) Sludge, silt, various mounds and humus with organic matter content exceeding 8% removed from the site cannot be used as backfill soil, and the remaining soil can be used as backfill soil. The backfill should be compacted in layers, with a compaction of the backfill ≥94%. (3) When backfilling, the south-side of the excavation should be reconstructed at the same time to prevent damage to the structure by asymmetric loads. 4) The roof should be waterproofed and backfilled, and prolonged exposure to the sun should cause temperature cracks in the structure.