Santa Clara County Municipal Code Part 3 Fills

Fill shall be constructed in layers. The loose thickness of each layer of fill material before compaction shall not exceed eight inches. Completed fills shall be stable masses of well integrated materials bonded to adjacent materials and to the materials on which they rest. Fills shall be competent to support anticipated loads and be stable at the design slopes shown on the plans. Proper drainage and other appropriate measures shall be taken to ensure the continuing integrity of fills.

(Ord. No. NS-1203.120, § 1, 4-9-13)

All fills shall be compacted throughout their full extent to a minimum of 90 percent of maximum density as determined by Test Method No. Calif. 216-G, or other alternate methods approved by the Grading Official. Sufficient tests shall be made for reasonable assurance of compliance with the provisions of this chapter.

EXCEPTIONS:

(a) Compaction may be less than 90 percent of maximum density, as determined by the above test, within six inches of the slope surface when such surface material is placed and compacted by a method acceptable to the Grading Official for the planting of the slopes.

(a) Fills not intended to support structures or roads need not be compacted to these standards if the applicant's civil engineer determines that such compaction is unnecessary for stability, safety and the purpose of the grading, and the Grading Official concurs.

The Grading Official may require that an investigation be made by soils laboratory to establish the characteristics of the soil, the amount of settlement to be expected, and the susceptibility of the soil to erosion or slippage.

(Ord. No. NS-1203.120, § 1, 4-9-13)

The natural ground surface shall be prepared to receive fill by removing vegetation, non-complying fill, topsoil, or other incompetent material, and where slopes are five horizontal to one vertical, or steeper, by keying into competent material. The lowermost key shall be at least six feet wide, except where recommended by the civil engineer as not being necessary. Subdrains shall be provided under all fills placed in natural watercourses and in other locations where seepage is evident. Such subdrainage systems shall be of a material and design approved by the soils engineer and acceptable to Grading Official. The location of the subdrains shall be shown in plan and elevation views on the plan.

(Ord. No. NS-1203.120, § 1, 4-9-13)

No fill shall be made which creates an exposed surface steeper in average slope than two horizontal to one vertical, exclusive of benches and exclusive of surroundings described herein, unless permitted by the Grading Official after receipt of a report by a soils engineer, based on appropriate laboratory tests, certifying such steeper slope will be stable and support erosion control plantings. The Grading Official may require that the fill be constructed with an exposed surface flatter than two horizontal to one vertical, or may require such other measures as he deems necessary for stability and safety. Fill slopes shall be rounded into existing terrain to produce a contoured transition from fill face to natural ground and abutting cut or fill surfaces where conditions permit.

(Ord. No. NS-1203.120, § 1, 4-9-13)

No organic material shall be permitted in fills. Rock or similar irreducible material with a maximum dimension greater than eight inches shall not be buried or placed in fills within two feet of finished grade. When such greater size material is placed in fills it shall be done in accordance with recommendations of the soils engineer, and must be approved by the Grading Official.

(Ord. No. NS-1203.120, § 1, 4-9-13)

Fill slopes exceeding 30 feet in vertical height shall have drainage terraces at vertical intervals not exceeding 25 feet, except that where only one terrace is required, it shall be at approximately mid-height unless some other location is approved by the Grading Official. Such drainage terraces shall be at least six feet wide and shall be designed and constructed so as to provide a swale or ditch having a minimal depth of one foot and a longitudinal grade of not less than four percent nor more than 12 percent. There shall be no reduction in grade along the direction of flow unless the velocity of flow is such that slope debris will remain in suspension on the reduced grade. Down drains or drainage outlets shall be provided at approximately 300-foot intervals along the drainage terrace or an equivalent location. Down drains and drainage outlets shall be of approved materials and of adequate capacity to convey the intercepted waters to the point of disposal. The terrace, including the swale or ditch, shall be protected from erosion and the flow discharges into a safe disposal area. If the drainage discharges onto natural ground, adequate erosion prevention measures shall be provided.

(Ord. No. NS-1203.120, § 1, 4-9-13)

Fill placed on the top of an existing or proposed cut or natural slope shall be set back a minimum distance of six feet measured horizontally from the property line. Tests to determine the density of compacted fills shall be made on the basis of not less than one test for each two-foot vertical lift of the fill, but not less than one test for each 1,000 cubic yards of material placed. Additional density test at a point approximately one foot below the fill slope surface shall be made on the basis of not less than one test for each 1,000 square feet in slope surface, but not less than one test for each ten-foot vertical of slope height. Additional tests may be required throughout the fill as determined by the inspector for the County surveyor. All tests shall be reasonably uniformly distributed within the fill or fill slope surface. Results of such testing and location of tests shall be presented in the periodic and final reports.

(Ord. No. NS-1203.120, § 1, 4-9-13)

In areas intended or designed to support buildings, expansive soil shall not be placed within two feet of the finish grade in such building areas unless recommended by a civil engineer based on laboratory tests and certifying that a design of footings or floor slab or other procedure will alleviate problems created by placing the expansive soil within such building areas.

(Ord. No. NS-1203.120, § 1, 4-9-13)