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-3- <br />SUBSURFACE EXPLORATIONS <br />Subsurface conditions for this project were explored by two hollow-stem auger <br />borings at the approximate locations shown on the Site and Explorat�on Plan, <br />Figure 1. The exploratior.s were performed an May 13, 1991 and a. :�nced to <br />depths of approximately 52 feet below the existing ground surface. The <br />results of our explorations are presented on the logs of borings B-1 and B-2 <br />on Figure 2 and Figure 3. Boring B-1 was located in the field by a <br />representative af Snohomish County�P.U.D. No. 1 and was measured from existing <br />structures in the substatien. Boring B-2 was located outside of Snohomish <br />County P.U.D. property adjacent to the south_border of the substation and was <br />also located by measuring from existing�5tructures. An electrician from <br />Snohomish County P.U.D. was on site during the drilling of boring B-1. <br />The borings were drilled with a truck-mounted Acker Soil Max drill rig. <br />Hollow stem augers with a 8.75-inch outside diameter and a 4-inch inside <br />diameter were used to advance the boring.: Sampling was performed through the <br />hollow stem of the auger. � <br />Standard Penetration Tests (SPT) were taken at approximately 5-foot depth <br />intervals beginning at 2 feet with a two-inch diameter split-spoon sampler in <br />general accordance with ASTM D-1586. The split-spoon sampler typically was <br />� driven into the soil a distance of 18 inches (where possible) with a 140-pound <br />hammer freely falling from a height of 30 inches. Rer.orded blows for.each six <br />inches of penetration, or portian thereof, are shown an the boring logs. The <br />number of blows required to drive the sampler the last 12 inches is the <br />Standard Penetration R�sistance. This resistance, or blow count, provides a <br />qualitative measure of the relative density of granular soils and consistency <br />of cohesive soils. Representative portions of the split-spoon samples were <br />placed in jars, sealed and transported to our laboratory for further <br />observation. <br />An en9ineer from our firm was present throughout the field work program to <br />observe the explorations, assist in sampling, and to prepare the descriptive <br />logs of the exploratians. Soils were classified in general accordance with <br />ASTM D-2488, "Standard Practice for Description and Identification of Soils <br />co�m� c«,�,n� r�w <br />