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

Geotechnical Engineering Report lrerracon Proposed Flight Line Steam Line Project Boeing Everett Facility Everett, Washington January 17, 2012 Terracon Project No.: 81115085 Per the Modified Proctor Test(ASTM:D-1557) Material Type and Location Minimum Range of Moisture Contents for Compaction Compaction Relative to Optimum Requirement(%) Minimum Maximum Beneath foundations 95 -2% +2% Utilidor trench backfill 95 -2% +2% Aggregate base (beneath pavements) 95 -2% +2% 4.2.9 Trench Backfill at Utilidor Phase 1 & 2 Transition Zone , We understand that construction of the utilidor will be phased in order to maintain one open airplane tow path throughout the construction process. We understand that the southern 165 feet of the utilidor (Station 13+12 to 14+77) will be constructed, backfilled, and repaved during Phase 1. During Phase 2, the airplane tow path will be shifted south and will cross over the completed Phase 1 utilidor. Preliminary plans indicate that the outboard plane wheel will be located about 15 feet from the temporary end of the Phase 1 utilidor box culvert. The box culvert will have about 11/2 feet of cover at this location. We recommend that trench backfill near the end of the Phase 1 box culvert consist of Control Density Fill (CDF) to reduce the potential for temporary fill slope raveling and provide adequate support for airplane wheel loads. CDF should meet the requirements of Section 2-09.3(1)E, CDF or CLSM, as presented in the Washington State Department of Transportation (WSDOT) Standard Specifications for Road, Bridge, and Municipal Construction. We recommend that CDF be poured neat against the box culvert and the trench wall. The face of the CDF trench backfill should be near vertical and roughly coincident with the end of the temporary Phase 1 box culvert. We anticipate that wooden formwork may be needed to construct the near vertical I CDF face. The CDF should extend from the temporary end of the box culvert at least 10 feet back into the Phase 1 trench excavation and should extend up to the top of the box culvert. Section 4.4.3 of this report provides recommendations for a utilidor foundation drain system. The free draining aggregate and perforated pipe for this system must not become contaminated with CDF. Provisions should be included in the project plans to protect the foundation drain at CDF backfill locations. This could include the placement of a plastic sheet above the drainage system prior to CDF placement. Alternatively, the perforated drain pipe and free drainage aggregate could be replaced with a solid wall PVC pipe at the locations of CDF placement. Engineered fill placed above the CDF trench backfill and box culvert may consist of Gravel I Borrow or the planned pavement section Crushed Surfacing Top Course, as appropriate for the remaining limited excavation depth. We recommend that the toe of the engineered fill be located about 2 feet from the temporary end of the box culvert and have a maximum temporary slope inclination of 2H:1V. i Responsive • Resourceful • Reliable 10