C04 - Attachment 7 - SD_CS-05_Excavation_2022.docx

Natural Resources Conservation Service

Construction Specification SD-05 Excavation

1. Scope The work shall consist of excavation required by the drawings and specifications and disposal of the excavated material.

2. Classification Excavation is classified as common excavation, rock excavation, or unclassified excavation in accordance with the following definitions.

Common Excavation is defined as the excavation of all materials that can be excavated, transported, and unloaded using heavy ripping equipment and heavy rubber tired loaders or scrapers with pusher tractors or that can be excavated and dumped into place or loaded onto hauling equipment by excavators having a rated capacity of one cubic yard or larger and equipped with attachments (shovel, bucket, backhoe, dragline, or clam shell) appropriate to the material type, character, and nature of the materials. This classification includes rocks smaller than one cubic yard.

Rock Excavation is defined as the excavation of all hard, compacted, or cemented materials that require blasting or the use of unusually large ripping and excavating equipment. This classification includes the removal of isolated rocks larger than one cubic yard.

Unclassified Excavation is defined as the excavation of all materials (including rock) encountered, regardless of the nature of the material or the excavation method needed.

3. Use of Excavated Materials To the extent needed, all suitable materials from excavations shall be used in the construction of specified earth or rock fills. Suitability of materials for specific purposes will be determined by the Natural Resources Conservation Service (NRCS) inspector. The contractor shall not waste or otherwise dispose of suitable excavated materials.

4. Disposal of Waste Materials All surplus and unsuitable excavated materials as designated as waste shall be disposed of by the contractor at the locations shown on the drawings or designated by the landowner or NRCS inspector. The disposal site shall be left in a neat condition suitable to be seeded without additional shaping and sloped to provide drainage.

5. Excavation Limit Excavations shall comply with OSHA Construction Industry Standards (29CFR Part 1926) Subpart P, Excavations, Trenching, and Shoring. All excavations shall be completed and maintained in a safe and stable condition throughout the total construction phase. Structure and trench excavations shall be completed to the specified elevations and to the length and width required to safely install, adjust, and remove any forms, bracing, or supports necessary for the installation of the work. Excavations outside the lines and limits shown on the drawings or specified herein required to meet safety requirements shall be the responsibility of the contractor in constructing and maintaining a safe and stable excavation.

6. Borrow Excavation When suitable materials from specified excavations are insufficient to construct specified earthfills and earth backfills, additional material shall be obtained from designated borrow areas. The extent and depth of borrow pits shall be as approved by the NRCS inspector.

Borrow pits must be shaped to eliminate unsightly conditions and steep or unstable slopes. Borrow areas shall be excavated and finally dressed to blend with the existing topography and sloped to prevent ponding and to provide drainage. All borrow sites shall be left in a neat condition suitable to be seeded without additional shaping.

7. Overexcavation Excavation in earth beyond the specified lines and grades shall be corrected by filling the resulting voids with approved, compacted earthfill. The exception to this is that if the earth is to become the subgrade for riprap, rockfill, sand or gravel bedding, or drainfill, the voids may be filled with material conforming to the specifications for the riprap, rockfill, bedding, or drainfill. Before correcting an overexcavation condition, the contractor shall review the planned corrective action with the engineer and obtain approval of the corrective measures.

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