(A) General. Unless otherwise recommended in the approved soils engineering or engineering geology report, fills shall conform to the provisions of this section. Any soils engineering or engineering geology report shall be sealed by an appropriately registered engineer in the State of Arizona. In the absence of an approved soils engineering report, these provisions may be waived for minor fills (less than six inches deep) not intended to support structures.
(B) Preparation of ground. Fill slopes shall not be constructed on natural slopes steeper than 1 unit vertical in 2 units horizontal (50% slope). The ground surface shall be prepared to receive fill by removing vegetation, non-complying fill, topsoil and other unsuitable materials scarifying to provide a bond with the new fill and, where slopes are steeper than 1 unit vertical in 5 units horizontal (20% slope) and the height is greater than 5 feet, by benching into sound bedrock or other competent material as determined by the soils engineer. The bench under the toe of a fill on a slope steeper than 1 unit vertical in 5 units horizontal (20% slope) shall be at least 10 feet wide. The area beyond the toe of fill shall be sloped for sheet overflow or a paved drain shall be provided. When fill is to be placed over a cut, the bench under the toe of fill shall be at least 10 feet wide but the cut shall be made before placing the fill and acceptance by the soils engineer or engineering geologist or both as suitable foundation for fills.
(C) Fill material. Detrimental amounts of organic material shall not be permitted in fills. Except as permitted by the Town Engineer, no rock or similar irreducible material with a maximum dimension greater than 12 inches shall be buried or placed in fills.
(D) Exception. The Town Engineer may permit placement of larger rock in fills when the following conditions are followed:
(1) When a soils engineer properly devises a method of placement, and continuously inspects its placement and approves the fill stability.
(2) Rock sizes greater than 12 inches in maximum dimension shall be 10 feet or more below grade, measured vertically.
(3) Rocks shall be placed so as to assure filling of all voids with well-graded soil.
(E) Compaction. All fills shall be compacted to a minimum of 90% of maximum density for all areas not under a structure. Any compaction in a fill under a structure shall meet the Building Department requirements.
(F) Slope of fill. The slope of fill surfaces shall be no steeper than is safe for the intended use. Fill slopes steeper than 1 unit vertical to 3 units horizontal (33.3% slope) shall be protected from erosion by rip-rap being an average size of 6 inches in diameter, or larger. Exceptions may be made for revegetating the slope to provide stability and erosion protection. Fill slopes shall be no steeper than 1 unit vertical to 2 units horizontal (50% slope) unless the permittee furnishes a soils engineering or an engineering geology report, or both, stating that the site has been investigated and giving an opinion that a fill at a steeper slope will be stable and not erode and will not create a hazard to public or private property.
(Res. 1637, passed 2-28-02; Am. 782, passed 6-3-10; Am. Res. 2871, passed 9-17-15; Am. Ord. 872, passed 9-17-15)