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Construction Report -Section 28 Pond <br />Proctor Samples P9 and P10 were obtained from the colluvial fan deposit borrow site <br />permitted under TR-68. These two samples represent the significant majority of the <br />compacted fill. <br />All four samples (P7, T8, P9, and P10) yielded a maximum density of between 111 and <br />116 pounds per cubic foot. See Attachment 2 for a listing of the laboratory results. <br />The original design contained the following five specification items for embankment <br />material and construction procedures. These were adopted from the original <br />geotechnical report presented in Volume 13, Exhibit 7, Part F and are presented below: <br />1) Site Preparation <br />Prior to placing fill the area should be stripped of organic topsoil or other deleterious <br />materials. <br />2) Acceptable Fill Materials <br />Suitable fill materials can be obtained from pond excavations or from nearby borrow <br />sources. Suitable materials include native clay soils, clayey sand soils, and bedrock <br />materials which are broken down to these soil types (SC, GC, CL and CH). bedrock <br />materials should be processed to produce asoil-like material with maximum particle size <br />of 6 inches. The materials used as embankment fill should have at least 25 percent <br />fines (material finer than no. 200 sieve). <br />3) Unacceptable Fill Materials <br />Materials not considered suitable for use as embankment fill include cleaner sand and <br />gravel. Also unacceptable are highly carbonaceous materials obtained from bedrock <br />excavations or well-cemented sandstones which do not break down to soil like <br />material. Highly organic soils or materials containing construction debris are also not <br />acceptable. Frozen soil is not acceptable. <br />4) Fill Placement and Compaction <br />Embankment fill should be placed in thin horizontal lifts (8 to 12 inches loose thickness.) <br />The fill should be moisture conditioned to within 2 percent of optimum moisture content <br />and compacted to at least 95 percent of standard proctor maximum dry density (ASTM <br />D-698). The placing and spreading of fill materials should be started at the lowest point <br />of the embankment. Fill placement and compaction should be observed and tested by <br />qualified geotechnical engineering firm. <br />5) Monitoring and Inspections <br />Monitoring and inspections should be pen`ormed by qualified individuals as outlined in <br />CDMG regulations. <br />Following receipt of the laboratory testing, it was determined that the some of the <br />available borrow materials were marginally outside of the range on the plasticity chart <br />for CL materials. Instead, two of the borrow samples (7P and 8P) were in the CL-ML <br />category. (Samples P5 and P6 were obtained from the interior of Prospect Pond, these <br />were initially envisioned as a source but ultimately were not used as a borrow source <br />and can be ignored.) Samples 9P and 10P were in the CL category and met the <br />original specification. See Attachment 1. After consultation with the geotechnical <br />Page 2 <br />