Australia Model Code of Practice: Excavation Work 3.5a: 3.5 Protect adjacent buildings and structures from collapse

Excavation can weaken the stability or security of a structure, or part of one, on or next to the site and lead to structural failure or collapse. Work must not begin until steps have been taken to prevent full or partial collapse of any building or structure that could be affected. Where digging goes below the footings of a structure, including retaining walls, and could affect its stability, a competent person should assess it and it should be secured by a ground support system designed by a competent person. A competent person should also identify any bracing the structure needs.