1329 MADRONA AVE Geotech Report 2022-10-25

• Subsurface Exploration,Geologic Hazard,and lanowicz Property Geotechnical Engineering Report Everett,Washington Project and Site Conditions Disturbed but representative samples were obtained by using the Standard Penetration Test (SPT) procedure in accordance with American Society for Testing and Materials(ASTM) D-1586. This test and sampling method consists of driving a standard, 2-inch outside-diameter, split-barrel sampler a distance of 18 inches into the soil with a 140-pound hammer free-falling a distance of 30 inches. The number of blows for each 6-inch interval is recorded, and the number of blows required to drive the sampler the final 12 inches is known as the Standard Penetration Resistance("N")or blow count. If a total of 50 blows are recorded at or before the end of one 6-inch interval, the blow count is recorded as the number of blows for the corresponding number of inches of penetration. The resistance, or N-value, provides a measure of the relative density of granular soils or the relative consistency of cohesive soils. These values are plotted on the attached boring logs. The samples obtained from the split-barrel sampler were classified in the field and representative portions placed in water-tight containers. The samples were then transported to our laboratory for further visual classification and geotechnical laboratory testing, as necessary. The various types of soil and groundwater elevations, as well as the depths where soil and • groundwater characteristics changed,are indicated on the exploration boring logs presented in the Appendix of this report. Our explorations and reconnaissance were approximately located by measuring from known site features. 4.0 SUBSURFACE CONDITIONS Subsurface conditions at the project site were inferred from the field explorations accomplished for this study,visual reconnaissance of the site, and review of applicable geologic literature. As shown on the field logs,the exploration borings encountered coiluvium, landslide deposits, and pre-Vashon non-glacial sediments. The following section presents more detailed subsurface information organized from the youngest to the oldest sediment types. 4.1 Stratigraphv Topsoil Topsoil was encountered at the surface to a depth of several inches in both exploration borings. These highly organic soils are unsuitable for structure and pavement support. Colluvium Loose, moist to wet, dark brown to gray, silty sand with varying gravel and silt contents was encountered to a depth of 13 feet in exploration boring EB-1. Medium stiff to very stiff sandy May 10,2018 ASSOCIATED EARTH SCIENCES,INC. NS/Id-170649E002-2-ProJects1 201 7064 91KE\WP Page 3