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AMERICAN ENGINEERING TESTING, INC. AET Project No. 26-00538 <br /> 6.5 Utility Support, Bedding and Backfilling <br /> We judge the existing soils below the current subgrade to be suitable for utility foundation <br /> support. If clayey or silty soils are present at the trench bottom, a 4-inch thick Granular bedding <br /> (MnIDOT Specification 3149.F) layer should be placed beneath pipes to improve support <br /> uniformity. <br /> Differing bedding thicknesses and/or material types may be needed if unstable soils or if water is <br /> present in the trench bottom. Additional details regarding utility bedding and utility backfilling <br /> can be found on the attached standard sheets entitled "Bedding/Foundation Support of Buried <br /> Pipe" and"Standard Recommendations for Utility Trench Backfilling". <br /> 7.0 CONSTRUCTION CONSIDERATIONS <br /> 7.1 Potential Difficulties <br /> 71.1 Runoff Water in Excavation <br /> Water can be expected to collect in the excavation bottom during times of inclement weather or <br /> snow melt. To allow observation of the excavation bottom, to reduce the potential for soil <br /> disturbance, and to facilitate filling operations, we recommend water be removed from within the <br /> excavation during construction. Based on the soils encountered, we anticipate the ground water <br /> can be handled with well points <br /> 7.1.2 Disturbance of Soils <br /> The on-site soils can become disturbed under construction traffic, especially if the soils are wet. <br /> If soils become disturbed, they should be subcut to the underlying undisturbed soils. The subeut <br /> soils can then be dried and recompacted back into place, or they should be removed and replaced <br /> with drier imported fill. <br /> Page 8 of 9 <br />