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vy « 4 I lee E . J k '45,`Y` G`5 2'' �?;c 4• , M1 >r r , y i 'v y pr`s y L r .. . « ,r, .. ;', • rte ,, le M x el ` 14 1 Oslo Road Improvement Project Page 4 File No . 11 -5420 4.0 CONCLUSIONS AND RECOMMENDATIONS 4 . 1 General Soil Stratigraphy for Roadway The results of the field exploration and laboratory testing programs are presented on the Soil Boring Profiles , Figures 4 and 5 . The stratification of the soil boring profiles represents our interpretation of the field boring logs and the results of the laboratory examination of the recovered samples. The stratification lines represent the approximate boundary between soil types . The actual transitions may be more gradual than implied . The results of our borings indicate the following general soil types : Stratum Classification No Description AASHTO index 505 Dark brown to dark gray slightly silty fine sand to silty fine sand with organics (topsoil) -- 1 Light gray to dark brown fine sand to slightly silty fine sand A-3 S 2 Light gray to dark brown slightly clayey fine sand A-2-4 S 3 Light gray to very dark gray clayey fine sand A-2-6 P 4 Very dark gray organic very clayey fine sand Soils encountered in the borings performed during this phase of exploration along Oslo Road typically included suitable sandy soils with variable amounts of clay and/or silt (AASHTO Classifications A-3 and A-24, Soil Stratum Nos . 1 and 2 ) overlying plastic clayey fine sand soils (A-2-6 , Stratum No . 3) . Soil Stratum Nos. 1 and 2 may be considered as select materials based on MOT criteria . The use of these soils relative to roadway construction should be in accordance with MOT Standard Index 505 . The Soil Stratum No . 3 soils (A-2 - 6) are deemed "plastic" and the Stratum No . 4 soils (A-8) "muck" by the FDOT and , as such , are typically considered unsuitable for use in roadway construction . We note that, while Soil Stratum No . 2 (A-2-4) is considered as select material based on MOT criteria, it is our opinion that this soil type may be problematic for roadway construction . The clay content is sufficient that this stratum will retain moisture resulting in compaction difficulties . Recommendations relative to the use of clayey soils are presented below in Section 4. 5 . Organic material or "topsoil" was encountered along the existing roadway throughout most of the project site to a depth of about 6 inches. The removal of topsoil and/or any other organic soils such as muck ( Soil Stratum No . 4) and plastic materials ( Soil Stratum No . 3) as encountered should be accomplished in accordance with MOT Standard Index 500 , unless otherwise noted on the plans . The stripped topsoil and any other organic or plastic soils should not be used for roadway construction or utility backfill . le ' A.; -