1010 N BROADWAY STARBUCKS Geotech Report 2025-07-24

Geotechnical Engineering Evaluation Irerracon Broadway& 10th Starbucks 0 Everett, WA January 9, 2014 = Terracon Project No. 81135080 4.2 Soil Stratigraphy Our exploratory borings revealed two primary soil types below the site, as described in the following paragraphs. The boring logs contained in Appendix A and the lab sheets contained in Appendix B provide details regarding on-site soil conditions. Although our scope of work did not involve any sampling or testing for possible environmental soil contaminants, it should be noted that we did not see any petroleum sheens or smell any petroleum odors in any of the soil samples that we obtained. a Granular Fill Soils: Immediately beneath the pavement, all four of our borings disclosed a surficial layer of dense silty sand with gravel. This layer measured approximately 3 feet thick in each of our borings. We infer this soil to be a layer of imported fill soil that was placed during the grading operations as a part of the current parking lot construction. Field moisture contents were measured at about 7 percent. a Native Glacial Till: Below the granular fill soils, we encountered a layer of dense to very dense silty sand with gravel to gravelly silty sand in each of the borings. We interpret the layer to be a glacially overridden till, as indicated on regional geologic maps. Our grain-size analyses performed on representative samples of the glacial till revealed a fines content (that portion passing the US No. 200 sieve) ranging from approximately 17 to 39 percent. In-situ moisture contents were measured on the order of 9 to 10 percent. 4.3 Groundwater Levels Each boring was observed while drilling and after completion for the presence and level of groundwater. Groundwater was not detected in any of the borings while drilling, or for the short duration that the borings were allowed to remain open after drilling. Groundwater level fluctuations occur due to seasonal variations in the amount of rainfall, runoff, and other factors not evident at the time the borings were performed. In addition, perched water can develop over low-permeability soil, such as the glacial till encountered below the existing fill. Therefore, groundwater levels during construction or at other times in the life of the structure may be higher or lower than the levels indicated on the boring logs. 5.0 CONCLUSIONS AND RECOMMENDATIONS Based on our surface reconnaissance, subsurface exploration, and document research, we conclude that the proposed site development is feasible from a geotechnical standpoint, contingent on proper design implementation and construction practices. Our geotechnical conclusions and recommendations concerning general considerations, site preparation, spread Reliable s Responsive ® Convenient s Innovative 5