04/25/96 Agenda & Packet - Laserfiche WebLink

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• AET #95-1343 - Page 5 other sites, we roughly estimate that future settlements of the existing athletic field area (no additional fill load imposed) would be on the order of 3" to 4" over the next 20 years. This settlement is estimated to be less than 1" in areas of thinner swamp deposits (such as Boring #2). Therefore, these predicted long-term settlements would likely be differential. Regrading activities will result in some areas receiving additional load, which would result in additional primary consolidation. As an example, if 3' of additional fill were placed in the deeper swamp deposit areas, settlements associated with primary consolidation are estimated to be on the order of 9" to 1'. This illustrates the settlement sensitivity of regrading. Also, we noted that a large stockpile currently exists at the site, which has likely resulted in local consolidation of the peats. Therefore, future differential settlements may occur between the land under the current stockpile versus the surrounding unloaded land. • Surface Stability The upper fill soils are anticipated to be relatively unstable under dymanic traffic loads. This would be a primary concern in the parking lot area. The extent of instability is likely a function of the amount of peat and organic clay intermixing, the depth at which these soils are intermixed, and the depth to the ground water table. Drainage For the most part, the on-site soil profile has moderate drainage properties. An exception may be where clay soils are present (such as at Boring #1) which can perch ground water if the clay has horizontal continuity. Also, the fine grained silty sands have the ability to "hold" a high water content. Frost Susceptibility The upper soils within the freezing zone are moderately high in frost susceptibility. The shallow • around water level and the potential for the on-site soils to allow capillary rise can result in ice lease formation, which can greatly exaggerate frost heaving.