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Report of Geotechnical Exploration West Armstrong Redevelopment Area, Ramsey, Minnesota March 30, 2022 AET Report No. P-0004952 6.0 RECOMMENDATIONS 6.1 Definitions AM EP I AN ENGINEERING TESTING The italicized words used in this section have specific definitions. These definitions are presented on the attached Standard Sheet entitled "Definitions Relating to Pavement Construction" or in ASTM Standards or MnDOT references. 6.2 Approach Discussion We recommend that at a minimum the upper foot of fill be removed from beneath the proposed roadway extension and removal of the existing bituminous and aggregate base in the reconstruction portion of the project. Additional topsoil or fill may need to be removed based on the organic content of the soils or if soft or loose soils are encountered. We recommend these soils be evaluated by AET geotechnical personnel before new fill is placed. A subgrade R-value of 50 can be assumed for the anticipated subgrade. 6.3 Subgrade Preparation To prepare the area for new roadway embankment placement, we recommend removing all existing pavement, aggregate base, and topsoil from below the roadway area. The excavation would need to include lateral oversizing to accommodate the lateral loads imposed. The soils exposed in the subgrade excavations are likely to consist of silty sands, sands with silt, and sands. We recommend these soils be evaluated by AET geotechnical personnel before new fill is placed. If soft or unstable soils are observed, then correction should be performed as needed by subcutting and replacing the inferior soils; or by scarification, drying, and re - compaction. Following excavation of inferior soils, new engineered fill can be placed as needed to re -attain subgrade elevation. Suitable Grading Material can be used as general embankment fill; except that where fill is placed over wet, unstable ground conditions or in standing water, cleaner granular soils should be used. The fill should be placed per the requirements of MnDOT Specification 2106.3G.1 (Specified Density Method). This specification requires soils placed within the critical subgrade zone be compacted to a minimum of 100% of the standard maximum dry unit weight defined in ASTM: D698 (Standard Proctor test), at a water content 65% to 102% of the standard optimum water content. This water content requirement does not apply to the sand subbase zone. A reduced Page 4 of 7