All backfilling shall be done with a clean cohesionless soil, such as sand or gravel, free from lumps and stone or, if approved by the Director, other material of equivalent compacting qualities. Broken pavement, large stones, roots and other debris shall not be used in the backfill. Such backfill shall be done in a manner that will permit the restoration of the surface to a density condition not less than that existing prior to excavation, unless otherwise specified. Backfill is required to be placed in lifts no greater than three feet in depth if a Hydro Hammer or other heavy compactor is to be used. Where hand compaction is to be done, the depth of the lift is limited to four inches. In the latter case, the number of men backfilling shall not exceed the number engaged in compacting. The Director may require soil tests to be furnished by a recognized soil-testing laboratory or registered professional engineer specializing in soil mechanics when, in his opinion, backfill for any excavation is not being adequately compacted. In order for the resurfacing to be permitted, such tests must show that the backfill material meets the minimum requirements as prescribed by the Director. All expenses of such tests shall be borne by the permittee.
(Ord. 3428-69. Passed 8-18-69.)