2600 FEDERAL AVE 2021 PORT OF EVERETT 2025-09-29

Substantive Requirements Review Landau Associates 3.2.2 Moisture Sensitivity and Reuse of Site Soils Excavated soils can be reused as fill, provided they are free of organic matter, construction debris, and other deleterious materials. Native soils that will be used as utility trench backfill should meet the gradation requirements in Section 9-03.19 of the 2020 WSDOT Standard Specifications. Significant construction debris and organic soils were observed at the site. Significant effort (i.e., screening or manual picking) may be required to process site soils. The sand fill placed during backfilling operations has a limited fines content and is suitable for reuse, provided it is properly placed and compacted. Some site soils are considered moisture sensitive. Moisture-sensitive soils may be difficult to compact without proper conditioning. If present, sand with limited fines can be segregated from fines-rich material to facilitate its reuse. 3.2.3 Wet Weather Earthwork Some site soils are considered moisture sensitive, and shallow groundwater is anticipated in some areas of the site. Performing earthwork during periods of wet weather or in wet conditions could result in disturbed soils and damaged subgrades. The Contractor should be responsible for preventing excessive erosion and ground destabilization during earthwork activities. If earthwork is performed during wet weather or in wet conditions, the Contractor may need to place granular fill to provide a stable working platform. The amount of fines allowed in granular and structural fill should be limited to 5 percent or less, by dry weight, based on the fraction passing the %-inch sieve. If wet weather earthwork is unavoidable, LAI recommends: • Performing earthwork in small sections to minimize subgrade disturbance. • Placing fill material immediately after subgrade preparation. • Implementing surface water-control measures to prevent run-on from entering excavations and fill soil stockpiles. • Removing wet surficial soil daily. Soil should be removed before fill is placed. • Sealing the soil surface with a smooth drum roller to reduce the extent to which soil becomes wet or unstable. 3.2.4 Temporary Construction Dewatering Groundwater is anticipated to be present from 1 to 12 ft bgs, with shallower groundwater conditions anticipated along the eastern edge of the site. Construction dewatering may be necessary for temporary utility excavations. Considerable dewatering effort should be anticipated in areas where the utilities will be installed below the groundwater table, in sandy or organic soils. The water level should be lowered at least 2 ft below the base of the excavation, including any overexcavation to remove unsuitable soils from beneath pipes (i.e., the base of the excavation is not necessarily at the same elevation as the bottom of the pipe bedding). Geotechnical Engineering Report 0121049.040.041 Norton Terminal Development&MTCA 3rd Interim Action 3-3 May 7,2021