1010 N BROADWAY EVCC 2018-01-01 MF Import

PROPOSED LIBERTY HALL.EVERETT COMMUNITY COLLEGE Everett.Washington underlain by dense to very dense sand. The materials encountered in the borings are described below. Asphalt. Asphalt pavement was observed in borings B-2 through B-7. The asphalt pavement varied from 31/2 to 51/2 inches thick. Approximately 3 inches of asphalt grindings were observed at the surface in boring B-1, which is the area being used as the contractor's lay down yard for the Student Health and Fitness Center project. Fill. Fill was observed in all borings to depths ranging from 1.5 to 9.5 feet below the existing • ground surface. The fill generally consists of soft to stiff silt and clay with variable sand and gravel content. During initial grading of the existing parking lot, multiple areas were overexcavated to remove unsuitable fill soils including tree stumps and logs. The overexcavated areas were backfilled with imported gravel borrow. Approximately 1 to 4-feet of recently placed structural fill associated with the overexcavations should be anticipated in the building footprint between gridlines 8 and 2'. Silt and Clay Soils. Compressible soft to medium stiff silt and clay soils were observed in several of the borings to depths up to 12 feet below the existing ground surface. The depth to dense bearing soils is summarized in Table 1. The compressible soils increase in depth from west to east across the building footprint such that dense soils are expected under the west foundations and up to 10 feet of compressible silt and clay will exist under the east foundations. Glacially Consolidated Soils. Glacially consolidated soils were observed in the borings from a depth of 21/2 feet to the depth explored. The glacially consolidated soils generally consisted of dense to very dense silty fine sand with occasional gravel and hard silt with fine sand. The glacially consolidated soils provide good foundation support for the building. TABLE 1. ELEVATION OF DENSE/VERY STIFF GLACIALLY CONSOLIDATED SOILS Exploration Approximate Ground Depth to Dense/Very Elevation of Dense/Very Surface Elevation(feet) Stiff Soils(feet) Stiff Soils(feet) B-1 89 2 87 B-2 90 1.5 88.5 B-3 86 2 84 B-4 88 3.5 84.5 B-5 86 8.5 77.5 B-6 87 7.5 79.5 B-7 83 9.5 73.5 Groundwater Conditions Perched groundwater was observed in all borings, except B-2, at depths ranging from 3 to 17.5 feet below the existing ground surface. Groundwater observations represent conditions observed during drilling and may not represent the groundwater conditions throughout the year. We anticipate shallow groundwater seepage will exist in permeable soils above the stiff to hard silt GEOENGINEERS ,lune 10,2010 Page ,-ite Dlo.5336 310 OC