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1 <br /> GEOENGLNEERS Memorandum <br /> 8410 154th Avenue NE,Redmond,WA 98052,Telephone:425.861.6000,Fax:425.861.6050 www.geoengineers.com <br /> To: Tim Gabelein, PE, Davido Consulting Group <br /> From: Debra Overbay, PE,GeoEngineers <br /> Date: July 15, 2013 <br /> File: 0120-279-00 <br /> Subject: Preliminary Geotechnical Summary <br /> E-6 Parking Lot Expansion, Boeing Everett, Washington <br /> INTRODUCTION <br /> This memorandum presents a preliminary summary of subsurface conditions encountered in support of the <br /> E-6 Parking Lot Expansion project to be constructed within the southeast corner of the Boeing Plant in <br /> Everett,Washington. Our services were requested to provide infiltration testing and recommendations for site <br /> preparation,earthwork, pavement design sections,and retaining walls. <br /> SITE CONDITIONS <br /> Surface Conditions <br /> We understand the E-6 Parking Lot will be expanded to the north and south by approximately 75 to 85 feet, <br /> I and to the west by approximately 60 feet. The proposed parking expansion area is currently vegetated with <br /> grass and landscaping. The overall site generally slopes down to the west,from about Elevation 553 feet on <br /> the east to a low ditch line at Elevation 546 feet in the west. <br /> Subsurface Conditions <br /> Subsurface Exploration <br /> ' Subsurface soil and groundwater conditions were evaluated by excavating seven test pits with a rubber-tired <br /> backhoe. Small scale pilot infiltration tests were completed in two of the test pits to measure the infiltration <br /> rate. The test pits were continuously monitored by a geotechnical engineer from our firm who examined and <br /> classified the soils encountered,obtained representative soil samples,observed groundwater conditions,and <br /> completed detailed logs of the test pits. All samples were taken to our laboratory for additional classification, <br /> moisture content testing, and sieve and hydrometer testing. Additional details of the field exploration <br /> program and laboratory testing will be provided in our final report. <br /> Soil Conditions and Preliminary Infiltration Rate <br /> Very dense glacial till was encountered at relatively shallow depths in the explorations completed to the north <br /> and south of the proposed parking expansion area. Dense silty sand fill was encountered in the western test <br /> pits. We completed a small scale pilot infiltration test(PIT) in two of the test pits. The results of the testing <br /> indicate an infiltration rate of 0.1 inches per hour or less. This low rate is considered as a hydraulic restriction <br /> layer(less than 0.3 inches per hour)and is not suitable for conventional permeable pavement design. <br /> 1 We trust this memorandum meets your immediate needs. Additional detailed recommendations and <br /> conclusions will be provided in our final report. Please contact us if you need additional information at <br /> this time. <br /> Disclaimer.Any electronic form,facsimile or hard copy of the original document(email,text,table,and/or figure),if provided,and any attachments are only a copy of <br /> the original document The original document is stored by GeoEngineers,Inc.and will serve as the official document of record. <br />