1315 MADRONA AVE 2016-01-01 MF Import

Geotechnical Engmeenng Report 1313 Madrona Avenue Everett, Washington Ntarch 11, 2013 RtJ Rle tJo 2793-001A Page 3 advance outwash was placed oy the advanc�ng glaciers and was everridden and �:ell compacted by the glacier Transitional Beds (Fraser Glaciation to Pre-Fraser Glaciation) (Qtb) -- 7hese deposrts consist of clay, sdt, and very fine to fine sand; some layers of peary sand and gravel are i� the lower part of compact but may be unstable because of high moisture content, plasticity, and Iocal vertical �ointing The sediments were mostly deposrted m still to slowly moving water. except for the coarse stream depos�ts in the Icwer part of the unit The geo�og�c urnts for this area are mapped on the Geoloo�c Map of the Everett Quadranqle Snohomish County. Washinqton, by James P. Minard N.S. Geological Survey, 1985) The site is mapped as being underlain by transitional bed depos�ts. Our ;ite exploratiors encountered glacial drift and outwash. Glacial dnft is s�m�lar to glaaal ull, bu; may ei:h�bit mere sort�ng of vanous soil grain sizes Explorations �Ve explored subsurface corditions �vithin the s�te on ivlarch i, 2013 by dnli�ng t�vo bormgs with a portable hollow stem auger dnli ng provided and operated by an mdependent drilling hrm ICN Drilling. IncJ, working under subcontract to Robinsen Noble, Inc- The bonngs were dnlled to depths oi 15Y: feet below [he ground surface. Samples were obtained from the borings at ?Ya foot interva�s by drivmg a split spoon sampler wrth a 140-pound hammer dropping 30 inches. The number of blows required for penetration of three 6 inch intervals was recorded To determine the standard penetration nwnber at that depth the number of blows required for the low�er two intervals are summed. If the number of blows reached 50 before the sampler �,vas dnven through any 6-inch intervai, the sampler was not driven further and the blow count was recorded as 50 for the actuai penetration distance. The �onngs were Iocated in the field by an engmeer from this firm who also examined the soils and geologic condrtions encouNered, and maintained logs of the borings. The approximate locations of the bonngs are shown on the Site Plan in Figure 2. The soils we�e wsually r.lass�iied in qeneral accordance with [he Unified Soil Classification System, a copy of which is presented as Figure 3. The logs of [he borings are presented m Figures 4 and 5 Subsurface Conditions A brief descnption of the conditions encountered in our explorations is included below f-or a more detailed descnption oi the soils encountered, review the boring logs in Figures 4 and 5. Our exploraUons generally encountered a surficial layer of topsoil that was 1 foot or less in thic4:ness. The topsoil consisted of loose, dar4; brown to black sandy silt to silty sand wRh organics. Underlymg the topsoil we encountered loose to dense silty sand and sand with sili with varymg amounts of gravel Ihat was inierpreted as glacial drift to a depth of about 9Y: feet in both borings. Underlying the glacial dn(t we encountered very dense fine to coarse sand with varying amounts o( silt and gravel that was interpreted as advance ou��vash In both bonngs this matenal extended to the full depths explored of 15'G• feet. Rob�nsun Noble, Inc