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3. EXPLORATION RESULTS 3.1 Site and Geology The borings were completed through the bituminous pavement section in the drive lanes of Oneka Lake Boulevard and Harrow Avenue North. Boring elevations ranged from about 925.3 to 942.5 feet, and indicate a moderately undulating terrain. The Washington County Geologic Atlas indicates the surficial geology of the area is mostly lake deposited sand and pockets of organic deposits. 3.2 Subsurface Soil and Groundwater Conditions The boring profile generally consisted of the pavement section and fill materials overlying lake deposited sandy soils. Boring PB -13 encountered organic deposits below the fills. Pavement Section The pavement section generally consisted of about 4 to 5 inches of bituminous asphalt, with an average of 4 inches, and about 6 to 12 inches of aggregate base, with an average of 10 inches. Fills The fills encountered in the borings generally consisted of a mixture of sands with silt and sands with gravel. These fills were commonly encountered to depths of about 2'/2 to 3 feet below grade, but at Boring PB -5 was encountered to a depth of about 6 feet and at Boring PB -13 was encountered to a depth of about 5 feet. Organics Boring PB -13 encountered peat and clays with organics below the fill materials. These organic soils were encountered to a depth of about 20 feet below grade. The organic soils were black in color and generally wet to saturated. Lake deposits The lake (lacustrine) deposits encountered in the borings ranged from sands with silt to silty sands to silty sands with clay. These soils were brown in color where encountered in the upper 15 feet of the boring, and at Boring PB -13 were gray to dark brown to brown in color. These soils were moist to wet to waterbearing. 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 borings completed and remarks regarding the material strengths of the soils. Table 1: Penetration Resistances Soil Type Classification Penetration Remarks Resistances Fill Varies 5 to 8 BPF Poorly compacted Peat / Organics PT, OL 2 to 3 BPF Very soft Lake Deposits SP -SM, SM, SC 2 to 20 BPF Very loose to medium dense Average 8 /2 BPF Generally loose Geotechnical Report Oneka Lake Boulevard and Harrow Avenue Improvements Hugo, Minnesota WSB Project No. 010893-000 Page 3