1802 75TH ST SW Geotech Report 2022-10-25

-3- • gradation of imported fill and backfill materials, backfill compaction requirements and earthwork construction consideration, • stripping depths and removal of other unsuitable materials if needed, • site grading and drainage. 5. Providing soil parameters for the MFAD (formerly PADALL) computer analysis program developed by the Electrical Power Research Institute for drilled shaft and direct embedment foundations. The parameters include data on soil type, friction angle, cohesion, total unit weight, modulus of deformation, bearing capacity and skin friction. SUBSURFACE.EXPLORATIONS AND LABORATORY TESTING PROGRAM Subsurface conditions for this project were explored by two hollow -stern auger borings at the approximate locations shown on the Site and Exploration Plan, Figure 1. The explorations were performed on May 13, 1991 and advanced to a depth of 15.5 feet each. The results of our exploration are presented on boring log B-1 and B-2 on Figure 2 and Figure 3. The explorations were located in the field by a representative of Snohomish County PUD No. 1 and ! were measured from existing structures in the substation. An electrician from Snohomish County PUD was on -site during all of the work. The borings were advanced with a truck -mounted Acker Soil Max drill rig. Hollow stem augers with a 8.75-inch outside diameter and a 4-inch inside j diameter were used to advance the boring. Sampling was performed through the hollow stem of the auger. I Standard Penetration Tests (SPT) were taken at approximately 2.5-foot depth intervals for the first 10 feet of the boring and 5-foot intervals for depths greater than 10 feet with a two-inch diameter split -spoon sampler in general accordance with ASTM D-1586. The split -spoon sampler was driven into the soil a distance of 18 inches (where possible) with a 140-pound hammer freely falling from a height of 30 inches. Recorded blows for each six inches of penetration, or portion thereof, are shown on the boring logs. The number {} of blows required to drive the sampler the last 12 inches is the Standard Converse Consultants NW