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<br />5 <br /> <br />Changes in the nature, design or location of all or parts of this project may occur. If so, we <br />should be informed as additional analysis and revised recommendations may be necessary. <br /> <br />4.2 Discussion <br /> <br />Aggregate Base/Possible Aggregate Base Soil borings SB-1 and SB-3 were completed within <br />or near the gravel driveway. Soil boring SB-1 encountered about 5 inches of aggregate that <br />appeared to be a crushed limestone product. The aggregate base at SB-1 had a P-200 content <br />within the range for MN/DOT aggregate base which suggest that the material might be <br />suitable for reuse as Class 5 Aggregate base. If the material will be salvaged and reused <br />additional samples should be collected and analyzed to confirm that the material meets the <br />full gradation requirements for MN/DOT Class 5 aggregate base. <br /> <br />The Possible Aggregate base at boring SB-3 had a P-200 content of about 26 ½ percent which <br />was significantly greater than MN/DOT requirements. The aggregate base at boring SB-3 will <br />likely not be suitable for reuse as MN/DOT Class 5 aggregate base. <br /> <br />Subgrade Soils New watermain, storm sewer and sanitary sewer utilities could be installed <br />as part of this project. We anticipate that new utilities will bear at depths ranging from about <br />5 to 10 feet below the ground surface. At these depths, we anticipate that the pipes will bear <br />on medium to stiff native glacial till soils or compacted engineered fill which in our opinion <br />are suitable for pipe support. <br /> <br />The clayey glacial till soil in our opinion are suitable for pavement support. However, these <br />soils are moderately to highly frost susceptible and can heave if they become saturated and <br />heave. To reduce the effects of frost heave you may wish to consider using a 12 to 18-inch- <br />thick drained sand sub-base below the aggregate base course. <br /> <br />Portion of the clayey soil had a rather soft consistency and because of that some soft soils could <br />be encountered during utility installation and/or during proof-rolling of the roadway <br />subgrade. Soft soils, if any, will need to be removed and replaced with suitable compacted <br />engineered fill or excavated, dried and recompacted. Soils that cannot be dried and <br />recompacted may need to be replaced with suitable materials. <br /> <br />Laboratory Moisture Contents Laboratory moisture content of the clayey soils ranged from <br />about 20 to 26 ½ percent indicating that the soils were likely above their assumed optimum <br />soil moisture content. Clayey soils that will be reused as fill or backfill will likely need to <br />moisture conditioned (dried) to meet the recommend compaction levels. Summer months are <br />typically more favorable for drying wet clays. <br /> <br />Groundwater Groundwater was not encountered in the soil boring while drilling and <br />sampling or after removing the augers from the boreholes. We do not anticipate that <br />groundwater will be encountered during construction and do not anticipate that dewatering <br />will be required. <br /> <br /> <br /> <br /> <br /> <br />211