3003 W CASINO RD BLDG 45-06 Geotech Report 2025-03-03

Geotechnical Engineering Report Proposed Flight Line Steam Line Project lierracon ' Boeing Everett Facility • Everett, Washington January 17, 2012 • Terracon Project No.: 81115085 'I . For passive earth pressure to develop, wall must move horizontally to mobilize resistance. • Uniform surcharge, where S is surcharge pressure • In-situ soil backfill weight a maximum of 125 pcf 'I . Horizontal backfill • Loading from heavy compaction equipment not included • No hydrostatic pressures acting on wall ■ No safety factor included in soil parameters • Ignore passive pressure in frost zone ' Backfill placed against structures should consist of granular soils. To calculate the resistance to sliding, a value of 0.45 should be used as the ultimate coefficient of friction between the footing and ' the underlying soil. Passive resistance may be used in combination with sliding friction to resist lateral loads. Backfill within 3 feet of the wall should be compacted to 95 percent of modified Proctor maximum dry density per ASTM:D-1557 by small, hand-operated compaction equipment to prevent the buildup of excess lateral soil pressures due to over compaction of backfill against 111 the wall. Construction monitoring should be provided to determine actual compaction percentages, and over compaction should not be allowed. All remaining backfill should be compacted in accordance with the recommendations provided in the Engineered Fill and ' Compaction sections of this report. 1 To control hydrostatic pressure behind the wall, we recommend that granular, free-draining material be placed directly behind the walls, extending from the bottom of the wall to the top of the wall. The free-draining material should meet the requirements of Section 9-03.14(1), Gravel Borrow, as presented in the Washington State Department of Transportation (WSDOT) Standard Specifications for Road, Bridge, and Municipal Construction. Site soils do not appear to meet the requirements of Gravel Borrow, and as a result, this material will likely need to be imported. A minimum 6-inch diameter, rigid, perforated PVC drain pipe should be placed at the bottom of the wall as outlined in Foundation Drains section of this report. The lateral earth pressures discussed above do not include the influence of surcharge, equipment, or floor loading, which should be added. Heavy equipment should not operate within a distance closer than the exposed height of retaining walls to prevent lateral pressures more than those provided. 4.6 Utilidor Lid Surcharge Load Considerations Preliminary plans indicate that the top or lid of the utilidor will have a varying thickness of cover along the alignment. Surcharge loads applied at the ground surface (such as airplane wheel loads or equipment loads) will dissipate with depth. The change in pressure at depth below a surcharge may be calculated using the 1 H:2V slope method. If the stress zone is defined by a Responsive • Resourceful • Reliable 17