Preliminary Geotechnical Engineering Report <br />Project No. 18-4986, 177 Day Island Road, Eugene, Oregon <br />NO " <br />unyielding condition, over-excavated and replaced with engineered fill (as described below) or <br />stabilized with rock prior to placement of engineered fill. The depth of over-excavation, if required, <br />should be evaluated by the geotechnical engineer at the time of construction. <br />Engineered Fill <br />All grading for the proposed development should be performed as engineered grading in <br />accordance with the applicable building code at time of construction with the exceptions and <br />additions noted herein. Proper test frequency and earthwork documentation usually requires daily <br />observation and testing during stripping, rough grading, and placement of engineered fill. Imported <br />fill material must be approved by the geotechnical engineer prior to being imported to the site. <br />Oversize material greater than 6 inches in size should not be used within 3 feet of foundation <br />footings, and material greater than 12 inches in diameter should not be used in engineered fill. <br />Engineered fill should be compacted in horizontal lifts not exceeding 8 inches using standard <br />compaction equipment. We recommend that engineered fill be compacted to at least 90% of the <br />maximum dry density determined by ASTM D1557 (Modified Proctor) or equivalent. Field density <br />testing should conform to ASTM D2922 and D3017, or D1556. All engineered fill should be <br />observed and tested by the project geotechnical engineer or his representative. Rocky fill may <br />need to be evaluated by proofrolling and should be placed wet of optimum moisture content. <br />Typically, one density test is performed for at least every 2 vertical feet of fill placed or every 500 <br />yd3, whichever requires more testing. Because testing is performed on an on-call basis, we <br />recommend that the earthwork contractor be held contractually responsible for test scheduling and <br />frequency. <br />Site earthwork will be impacted by soil moisture and shallow groundwater conditions. Earthwork in <br />wet weather would likely require extensive use of cement or lime treatment, or other special <br />measures, at considerable additional cost compared to earthwork performed under dry-weather <br />conditions. <br />Excavating Conditions and Utility Trench Backfill <br />All temporary cuts in excess of 4 feet in height should be sloped in accordance with U.S. <br />Occupational Safety and Health Administration (OSHA) regulations (29 CFR Part 1926) or be <br />shored. The existing native soils classify as Type B Soil and temporary excavation side slope <br />inclinations as steep as 1 H:1 V may be assumed for planning purposes. This cut slope inclination <br />is applicable to excavations above the water table only. Maintenance of safe working conditions, <br />including temporary excavation stability, is the responsibility of the contractor. Actual slope <br />inclinations at the time of construction should be determined based on safety requirements and <br />actual soil and groundwater conditions. <br />Saturated soils and groundwater may be encountered in utility trenches, particularly during the wet <br />season. Adequate shoring should be maintained. We anticipate that dewatering systems <br />consisting of ditches, sumps and pumps would be adequate for control of perched groundwater. <br />18-4986, 177 Day Island Road GRPT 6 GEOPACIFIC ENGINEERING, INC. <br />Version 1, August 27, 2018 <br />