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I <br /> f <br /> Of t <br /> amec { ; <br /> foster I <br /> wheeler <br /> Geotechnical laboratory tests revealed that the lacustrine silts had a fines (silt and clay) content that <br /> ranged from 70 to 90 percent, with high moisture content that ranged from 16 to 36 percent. We <br /> interpret the lacustrine silts to be above their optimum moisture content for compaction and highly <br /> sensitive to additional moisture content. The Advance Outwash sand and gravel had a fines content <br /> ranging from 10 to 18 percent with a moisture content between 5 and 12 percent. We interpret the <br /> Advance Outwash soils to be near optimum moisture content for compaction and moderately sensitive I <br /> to additional moisture content. The laboratory testing sheets presented in Appendix B graphically <br /> present the laboratory test results, and Table 3 summarizes these results. <br /> Table 3 Laboratory Test Results <br /> Moisture Grain Size Distribution11 <br /> Sample Content Gravel Sand Silt/Clay <br /> Number Depth (feet) Soil Type (percent) (percent) (percent) (percent) <br /> B-1/S-2 5.0—6.5 Silt 32 N/T N/T 88 <br /> B-1/S-6 20—21.5 Gravelly Sand 6 0.0 90 10 <br /> B-2/S-2 5.0—6.5 Silt 25 0.0 14 86 <br /> B-2/S-4 12.5— 14.5 Silt 16 N/T N/T N/T <br /> B-2/S-5 17.5—19 Gravelly Sand 12 1.0 82 18 <br /> B-3/S-2 5.0—6.5 Silt 26 N/T N/T 74 I <br /> B-3/S-4 12.5- 14 Gravelly Sand 5 9 75 16 <br /> B-3/S-5 17.5 - 19 Gravelly Sand 6 N/T N/T 10 <br /> B-4/S-1 2.5—4.0 Silt 26 0.0 10 90 <br /> B-4/S-4 12.5—14 Silt 21 N/T N/T N/T <br /> B-5/S-2 5.0—6.5 Silt 28 N/T N/T 70 <br /> B-5/S-3 7.5—9.0 Silt 27 N/T N/T N/T ' <br /> B-5/S-5 17.5—19 Silty Sand 6 0.0 82 18 <br /> B-6/S-2C 6.0 6.5 Silt 27 N/T N/T 78 <br /> B-6/S-4 12.5-14.0 Silt 36 N/T N/T N/T <br /> N/T=Not tested <br /> 3.3 GROUNDWATER CONDITIONS I <br /> At the time of our exploration (September 6, 2016), none of our explorations encountered <br /> groundwater at depth. However, mottling and oxidation staining were noted in some of the soil <br /> samples collected, indicating a possible fluctuating groundwater table. We did encounter shallow <br /> perched groundwater at the drainage sand-soil subgrade contact in boring B-1, which was advanced <br /> near the center of the athletic field. The perched groundwater appeared to be caused by the athletic I <br /> field irrigation system. <br /> Because our explorations were performed during the generally dry summer season, the groundwater I <br /> conditions present at this time may closely represent the yearly low level. Yearly groundwater high <br /> Amec Foster Wheeler I <br /> 6 Project No.6-917-18116-0 <br /> \\Sea-fs1\WordProc\ Projects\18000s\18116 Everett School District\Geotech Report\Revised\2017_10-19_Everett Middle School Geotech_Sx.docx <br />