8417 EVERGREEN WAY Geotech Report 2022-10-25

Geotechnical Engineering Report- Revised l�i�rracon Proposed CFT Retail Everett,Washington February 1, 2018 Terracon Project No. 81185002 Based on our review of the Washington Interactive Geologic Map available online (https://fortress.wa.qov/dnr/protectiongis/geology/?Theme=wigm), the nearest fault to the project site is the Southern Whidbey Island fault zone approximately 21A miles west of the project site. According to the USGS, the fault age is less than 15,000 years and has been mapped as an inferred fault trace. Based on the information described above, we estimate that the risk associated with surface rupture at the site is low. The risk of liquefaction was evaluated and based on our understanding of groundwater and geology at the site, it is our opinion that the risk of liquefaction is low. 4.6 Lateral Earth Pressures The proposed site development does not indicate for a retaining wall to be built. However,temporary shoring may be necessary as construction continues. The lateral earth pressure recommendations herein are applicable to the design of rigid retaining walls subject to slight rotation, such as cantilever, or gravity type concrete walls. These recommendations are not applicable to the design of modular block, geogrid-reinforced backfill walls or rockeries. If these types of walls are preferred, Terracon is available to provide additional recommendations or design services. For active pressure movement S = Surcharge --►r 4 (0.002 H to 0.004 H) S For at-rest pressure - No Movement Assumed Horizontal • Finished Grade H Horizontal Finished Grade —p2 -p,-+I Retaining Wall EARTH EARTH PRESSURE EQUIVALENT SURCHARGE EARTH PRESSURE FLUID DENSITY PRESSURE, pi PRESSURE, p2 CONDITIONS ONDITIONS (pcf) (psf) (psf) Active (Ka) 0.28 36 (0.28)S (36)H At-Rest(Ko) 0.44 57 (0.44)S (57)H Passive(Kp) 3.5 450 --- --- Responsive Resourceful Reliable 14