1321 COLBY AVE 1988 PARKING GARAGE AND MEDICAL OFFICE BUILDING Geotech Report 2018-01-02 MF Import

Everett General Hospital & Medical Center W-5557 29 March 1988 Page 3 3.1 Subsurface Conditions The subsurface exploration program for this study encountered generally consistent subsurface conditions at depth. The borings encountered variable thicknesses of relatively loose fill , organic-rich topsoil , and loose to medium dense native soils overlying very dense, gravelly, silty sand. The very dense, gravelly, silty sand was apparently deposited and subsequently overridden by glaciers, and is generally referred to as "glacial till". Because of the previous load history, this soil is of relatively high strength and low compressibility. The depth to the top of very dense glacial till varies from approximately 3-1/2 to 9 feet below existing ground surface, at the boring locations. The approximate elevation of the top of very dense soil suitable for foundation support is noted for each of the boring locations on Figure 1 of this report. Soils overlying the glacial till consist generally of loose to medium dense, gravelly, silty sand. Occasional zones of organic-rich old topsoil, and wet, fine sandy silt were also encountered above the very dense soils. Boring B-1 also encountered wet, fine sandy silt interlayered with very dense gravelly sand, at a depth of approximately 7 to 9 feet. No free ground water was encountered in the borings. We would anticipate that the ground water conditions will fluctuate due to variations in season, rainfall, changes in site utilization and other factors. Ground water should be anticipated at random depths within the existing fill soils, and near the fill/natural soil interface. 3.3 Previous Soils Explorations Soils reports by Pittsburgh Testing Laboratory for the previously proposed additions and parking garage at Everett General Hospital were reviewed for this study. The reports are dated 8 July 1980. A total of seven borings were completed within the general vicinity of the currently proposed site improvements. Those boring logs I are included with this report. In general , the boring logs indicate similar soils 1 as encountered in our study at depth. The depth to the top of very dense native soil is not well-defined on the previous borings, however. On Figure 1 of this report, we have indicated our interpretation of the top of very dense soils based 1 on the Pittsburgh Testing Laboratory boring logs. It should be noted that the