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3. EXPLORATION RESULTS 3.1 Site and Geology The borings were performed on existing roadway alignments as described above in Section 1.1. The Ramsey County Geologic Atlas indicated the surficial geology in the area of our borings are lacustrine (lake) deposits. These deposits consist primarily of sand, silty and clayey sands and clay. 3.2 Subsurface Soil and Groundwater Conditions Geologic origins can be difficult to determine solely from boring samples. We referenced online geologic data of the area and used our experience to help determine geologic origin of the soils, however only a detailed geologic exploration would accurately determine the geologic history of the site. The boring profile generally consisted of a pavement section overlying fill and/or naturally deposited glacial till. Pavement Section The bituminous thickness encountered in our borings ranged from about 3 to 5 inches and averaged about 4 inches. The underlying aggregate base ranged from about 3 to 9 inches and averaged under 6 '/2 inches. Fill With the exception of Boring PB-3 our borings encountered fill beneath the aggregate base. The fill consisted mainly of sand with silt that was dark brown to brown and gray in color and generally moist. Borings PB-8 and PB-10 encountered fill that consisted of lean clay that appeared to be mixed with sand. The lean clay fill was brown and moist. Naturally Deposited Soils Below the pavement section or fill, our borings encountered and terminated in lake-deposited soils. The lake deposits consisted of sand, sand with silt and lean clay. These soils were generally brown and moist to wet. It should be noted that much of the lean clay deposits contained sand lenses. 3.3 Strength Characteristics The penetration resistance N-values of the materials encountered were recorded during drilling and are indicated as blows per foot (BPF). Those values provide an indication of soil strength characteristics and are located on the boring log sheets. Also, visual-manual classification techniques and apparent moisture contents were also utilized to make an engineering judgment of the consistency of the materials. Table 1 presents a summary of the penetration resistances in the soils for the standard penetration test borings completed and remarks regarding the material strengths of the soils. Table 1: Penetration Resistances Soil Type Classification Penetration Remarks Resistances Fill Varies 2 to 17 BPF Variable compaction Lacustrine (granular) SP, SP-SM 5 to 11 BPF Loose to medium dense Lacustrine (cohesive) CL 2 to 10 BPF Very soft to firm The preceding is a generalized description of soil conditions at this site. Variations from the generalized profile exist and should be assessed from the boring logs, the normal geologic character of the deposits, and the soils uncovered during site excavation. Geotechnical Report 2020 PMP Street Improvements Arden Hills,Minnesota WSB Project No.014297-000 Page 3