Backfilling and related work shall be so done, and the quality of the materials used shall be such, as to prevent the movement of the earth of adjoining properties or the subsequent caving-in of backfilled areas. Backfilling shall not be done until retaining walls, foundation walls, or other construction against which backfill is placed are in suitable condition to resist lateral pressure; and no backfilling shall be done by methods which may cause dislodgement of any retaining wall or other permanent structure.