Application Materials - Laserfiche WebLink

Preliminary Geotechnical Engineering Report Project No. 18-4986, 177 Day Island Road, Eugene, Oregon NO " 35 feet, medium dense silty SAND (SM) from 35 to 40 feet, and stiff to hard sandy elastic SILT (MH) below 40 feet. Based on the subsurface conditions encountered in our soil borings, we assume that groundwater levels are closely related to the level of water in the slough of the Willamette River adjacent to the site. We therefore assume that at the time of our site investigation on July 3, 2018 groundwater was present at a depth of approximately 5 feet below the ground surface. We reviewed the subsurface profile for potentially liquefiable layers. The layer of GRAVEL (GP) encountered from 5 to 15 feet is not considered susceptible to liquefaction due to the density of the material. The layers of elastic silt are not considered susceptible to liquefaction due to their stiffness and plasticity. The layer of silty SAND (SM) encountered from 35 to 40 feet in boring B-1 is not considered susceptible to liquefaction due to the density and the plasticity of the fines content. Based on our subsurface explorations and on the results of laboratory testing, the only potentially liquefiable layer identified in our explorations is the layer of loose SAND (SP) encountered to a depth of 5 feet in borings B-1 and B-2. As discussed in the sections of this report titled Site Preparation and Structural Foundations, the layer of loose SAND (SP) is to be removed and replaced with engineered fill as part of site development. Assuming that the loose SAND (SP) to a depth of 5 feet below the ground surface is replaced as recommended, it is our opinion that damage to the proposed structure due to liquefaction will be low and that no other special measures will be necessary to address liquefaction. 18-4986, 177 Day Island Road GRPT 16 GEOPACIFIC ENGINEERING, INC. Version 1, August 27, 2018