202 ALDER ST Geotech Report 2018-01-02 MF Import

1 ' Proposed blew R�dg: Subsurfare Ecploration, Geologir Hazards, Inj�l�ralion Potenlial, Elemenrarv Schoo7 Replacerrtent and Preliminary Geotechnical Engineenng Repon £veren. W¢shington Projec�and Si�e Condilions ' 3.1 Exploration Borings ' The exploration borings were completed by advancing hollow-stem auger tools with a track- mounted drill rig. During the drilling process, samples were obtained at generally 2.5- to 5-foot-depth intervals. The exploration borings were continuously observed and logged by a 1 representative from our firm. The exploration logs presented in the Appendix are based on the fie1J logs, drilling action, and inspection of the samples secured. , Disturbed but representative samptes were obtained by using the Standard Penetration Test (SPT) procedure in accordance with American Sociery for Testing and Materials ' (ASTM):D 1586. This test and sampling method consists of driving a standard, 2-inch outside-diamerer, 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. lf a total of 50 is recorded within 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 densiry of granulaz soils or the relative consistency of cohesive soils; these values are plotted on the attached exploratiun boring logs. ' The samples obtained from the split-barre( sampler were classified in the field and ' representative portions placed in watertight containers. The samples were [hen transported to our laboratory for further visual classification and laboratory testing, as necessazy. ' 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 selected appiicable geologi� lirerature. Because of the nature of exploratory work below ground, �xtrapolatio❑ of ' subsurface conditions between field explorations is necessazy. It should be noted that differing subsurface conditions may sometimes be present due to the random nature of deposition and , the alreration of topography by past gradmg and/or filling. The namre and extent of any variations between the field explorations may not become fully evident until construction. ' 1 ' September 22, 20/0 ASSOClA7ED EAR7'H SCIENCES. lNC. BWG/rb�K£1GI255A1-Projen3�201001551KEiW!' PBgC 3 '