7818 LARIMER RD B Geotech Report 2022-10-25

Import soils should be approved by AGS prior to placement. Fill placement observations and fill compaction tests should be performed by AGS Engineering to minimize the potential for future problems. Fill material should not be placed on frozen ground. Vegetation, roots, topsoil, the existing fill materials, and other deleterious material to depth of approximately 6 inches should be removed before new fill material is placed. On -site fill to be placed should be moisture treated to within 2 percent of optimum moisture content (OMC) for sand fill. Fill to be placed in wall backfill areas and driveway areas and all other structural areas should be compacted to 95% of Modified Proctor (ASTM D1557) maximum dry density or greater. Compaction in landscape areas should be 85% or greater. Imported structural fill should consist of sand or gravel material with a maximum particle size of 3 inches or less. In addition, this material shall have a liquid limit less than 30 and a plasticity index of 15 or less. Structural fill should also have a percent fine between 15 to 30 percent passing the No. 200 sieve. Structural fill should be moisture conditioned to within 2 percent of OMC and compacted to at least 95 percent of Modified Proctor (ASTM D1557) maximum dry density. Excavation: In our opinion, the materials encountered at this site may be excavated with conventional mechanical excavating equipment. Although our borings did not encounter "buried" foundation elements or other structures or debris, these materials will most likely be encountered during excavation activities. Debris materials such as brick, wood, concrete, and abandoned utility lines, if encountered, should be removed from structural areas when encountered in excavations and either wasted from the site or placed in landscaped areas. Temporary excavations should comply with OSHA and other applicable federal, state, and local safety regulations. In our opinion, OSHA Type A soils will be encountered at this site during excavation. OSHA recommends maximum allowable unbraced temporary excavation slopes of 1.25:1(H:V) for Type A soils for excavations up to 10 feet deep. Permanent cut and fill slopes are anticipated to be stable at slope ratios as steep as 2H:1V (horizontal to vertical) under dry conditions. New slopes should be revegetated as soon as possible after completion to minimize erosion. We recommend a minimum of 15 feet of clearance between the top of excavation slopes and soil stockpiles or heavy equipment or adjacent structures (subject to approval of AGS). If braced excavations are to be used, they should be reviewed and designed by AGS. It should be noted that near -surface soils encountered at the site will be susceptible to some sloughing and excavations should be periodically monitored by AGS's representative. Proposed Construction Project No: 0470-WA18 January 24, 2019 Page No: 13 of 17