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Bus <br /> SUBSURFACE CONDITIONS <br /> SUBSOILS <br /> ' The information obtained from the soil borings indicates the site has relatively uniform <br /> subsurface conditions. The soil borings identified an upper stratum that extends to about 20 feet <br /> ' below the ground surface. This stratum consists of very moist, firm to stiff, low plasticity lean <br /> clay and sandy lean clay interbedded with pockets of a very moist, stiff, low plasticity silt and a <br /> very moist, medium dense, clayey sand. A second stratum extending to at least the termination <br /> of the borings, was below the upper stratum. This stratum is composed primarily of saturated, <br /> ' medium dense, fine-medium sand. Within these borings, as is typical with glacial outwash soil, <br /> seams, pockets and layers of sand, clayey sand and silty sand were found. <br /> ' The types, stratification and laboratory test results of the subsoils encountered within the depths <br /> drilled, are shown on the enclosed boring logs, as are the depths to groundwater, and other <br /> pertinent information (see Appendix B). <br /> ' GROUNDWATER <br /> Groundwater observations were made for each of the borings during the drilling procedure. The <br /> ' depth to free water was measured and found at a depth of 18.5 to 24.5 feet. The groundwater <br /> observations are shown on the boring logs. The water depths at the time of drilling should not <br /> be viewed as a permanent condition. Free subsurface water can often be found trapped in <br /> pervious zones within the upper loessial and outwash soil strata. This water is precipitation that <br /> seeps into these soils and becomes trapped. The resulting quantity and elevation of this type of <br /> groundwater will vary seasonally. The presence of water-bearing sand within the depths <br /> explored is indicative of the necessity of controlling large quantities of water during the <br /> construction phase of this project. <br /> Geotechnical Exploration for Sanitary Pipeline <br /> New Vulcan Waterline Pipeline, Decatur, Macon County, Illinois <br /> SKS Project No. 12-418885 Page 4 <br />