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I I I I I I I I I I I I I I I I I I I 06/07 b. Unsatisfactory soil materials are those defined in ASTM D-2321 soil classification designation Class IV and V along with peat and other highly organic soils. 2. Materials shall be furnished as required from off site sources and hauled to the site. B. Foundation 1. A stable foundation must be provided to insure proper line and grade is maintained. Unsuitable foundations must be stabilized at the engineer's direction. Unsuitable or unstable foundations may be undercut and replaced with a suitable bedding material, placed in 6" lifts. Other methods of stabilization, such as geotextiles may be appropriate based on the engineer's judgment. C. Bedding: 1. A stable and uniform bedding shall be provided for the pipe and any protruding features of its joints and/or fittings. The middle of the bedding equal to 1/3 of the 0.0. should be loosely placed, with the remainder compacted to a minimum of 90% standard proctor density. Class I, II, and III materials are suitable for use as bedding. D. Haunching 1. Proper haunching provides a major portion of the pipes strength and stability therefore care must be exercised in insure placement and compaction of the embedment material in the haunches. For larger diameter pipes (>30") embedment materials should be worked under the haunches by hand. Haunching materials may be Class I, II, or III and must be placed and compacted in 8" maximum lifts, compacted to 90% standard proctor density. E. Initial Backfill: 1. Initial backfill materials are required to a minimum of the pipe diameter for proper structural performance of the pipe. The ASTM specifications extend the initial backfill from the springline to 6"-12" above the pipe to provide protection for the pipe from construction operations during placement of the final backfill and protect the pipe form stones or cobbles in the final backfill. For proper structural performance of the pipe, the initial backfill need only extend to the pipe diameter. Class I, II, or III materials may be used as initial backfill however: a. Class I materials must be used in wet trenches if Class I bedding and haunching materials are used. b. Class II materials must be compacted in 6" lifts to 90% standard proctor density. c. Class III materials must be compacted in 6" lifts to 90% standard proctor density. 02221-4 03-4197