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88-082 <br />James McCaffrey -2- March 2, 1988 <br />classifications and strata depths were inferred from the <br />disturbed samples brought to the surface by rotation of the <br />auger. <br />Soils encountered in the borings were visually and manually <br />classified in the field by the crew chief in accordance with ASTM <br />D 2487 "Unified Soils Classification System" and ASTM D 2488 <br />"Recommended Practice for visual and Manual Description of <br />Soils." A copy of ASTM D 2487 is attached. All samples were <br />then returned to the laboratory for review of the field classifi- <br />cations by a soils engineer. Representative samples will remain <br />in our Minneapolis office for a period of 60 days to be available <br />for your examination. <br />Immediately after taking the final sample in the bottom of the <br />borings, we probed the bore holes with the hollow -stem auger in <br />the ground to check for ground water. In addition, immediately <br />after withdrawal of the auger, the bore holes were again probed <br />and the depth to cave-in and the presence or absence of water was <br />noted. The borings were then immediately backfilled. <br />RESULTS <br />Log of Boring sheets indicating `he depths and descriptions of <br />the various soil strata, the penetration resistances, and water <br />level information are attached. The depths shown as changes bet- <br />ween the strata are generally only approximate. The actual <br />changes are likely transitions, and the depths of the transitions <br />likely vary horizontally. <br />The borings typically encountered peat swamp deposits along the <br />driveway alignment. The peat extended to the 19-foot depth at <br />boring B-4 and 29 feet at borings B-1 and B-3. The borings were <br />then stopped in silty sand. The exception is boring B-1 which <br />had 2 1/2 feet of sand fill overlying the seat swamp deposits. <br />Ground water was encountered in the investigation with.n 1 to 2 <br />feet of the swamp grade. fluctuation in ground water will occur <br />due to seasonal and annual weather variations. <br />ANALYSIS AND RECOMMENDATIONS <br />It is our understanding that a driveway approximately 275 feet <br />long may be constructed across this existing marsh. The dri- <br />veway will be approximately 3 feet above existing swamp grade <br />and will be approximately 14 feet in width. <br />As requested, we have not completed an engineering analysis for <br />construction of the driveway across this marsh. If engineering <br />LPRAUR- <br />