6.6. SR 08-19-2002 - Laserfiche WebLink

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AET #20-02044 - Page 7 Movements of exterior sidewalks, slabs and stoops is especially important at building doorway areas. These exterior features should be designed to accommodate frost heave movements of the magnitudes described, or the on-site soils should be removed and replaced with non-frost susceptible sands. In bituminous parking and drive areas, frost heaving is not necessarily a problem unless the heave occurs as an abrupt differential movement. For this reason, consistency of soil conditions or gradual changes of the soil conditions across the pavement area is favorable. Drainage Properties The fine or mixed alluvial soils, glacial tills and the f'me grained silty sand parts of the coarse alluvium are judged to be slow to moderate draining soils. The coarse alluvial sands and sands with silt are judged to be moderately fast to fast draining. Pavement Stability Properties The fine alluvial lean clays and silts are judged to have low strength and pavement stability. The mixed alluvium, coarse alluvium and till soils are judged to have moderate strength and pavement stability. However, if these soils are wet, they can become unstable if subjected to repeated traffic. If they become unstable, they can be improved by subcutting, moisture conditioning, and then recompacting. This correction should be performed during favorable weather conditions, but is difficult to perform during the Spring and Fall of the year. Effect of Ground Water Basements should be positioned a safe distance above the water levels to allow for future fluctuations. The basement construction should include a perimeter draintile system to collect and dispose of perched or infiltrating surface runoff water. If larger quantities of water are present, use of additional trench drain systems may be needed in parts of the site. Since the soils are interlayered, there is a potential for water at variable elevations and use of trench drains may be