Agenda - Council - 06/27/2017 - Laserfiche WebLink

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Riverdale Drive Improvements Ramsey, Minnesota NTI Project No. 15.61197.100 The boring locations and depths were determined by Bolton & Menk, Inc. personnel. The borings terminated at nominal of 10 feet below the existing ground surface. NTI estimated ground surface elevations based upon publically available MNTopo LiDAR data. Subsurface conditions are summarized in the table below. Please refer to the boring logs for additional information. Table 1: Pavement and Subgrade Summary Apparent Boring Topsoil Fill) Subgrade Native Subgrade No. Thickness 1 Material Material (in) Notes B 1 18 SP-SM SP 4 1/2 Feet of Agricultural Till Zone/ Existing Fill B-2 10 SP-SM SP-SM 4 1/2Feet of Agricultural Till Zone/ Existing Fill B-3 18 NE 2 SP-SM B-4 SP-SM, SC SM 4 1/2Feet of Agricultural Till Zone/ Existing Fill B-5 8 SP-SM SP-SM 4 1/2Feet of Agricultural Till Zone/ Existing Fill 1. Material appeared to contain organic matter. This material may not necessarily meet MnDOT or other specifications for topsoil. 2. Fill not encountered in the soil boring. GROUNDWATER AND GROUNDWATER CONTROL Groundwater was not observed in our soil borings at the time of our explorations. Groundwater elevations can change due to precipitation events seasonally, changes in topography and site development, and due to long-term climate changes. Also, soil conditions between borings may be conducive to localized seeps or perched water zones that may be permanent or transient. UTILITIES The fill and native soils observed in soil borings were generally suitable for utility support. For utilities with planned invert elevations within the existing fill, we recommend that at least the upper 1 foot of the excavation subgrade be scarified, moisture conditioned and re -compacted. In addition, areas unstable or organic laden soils (if encountered) should be subcut and replaced with engineered fill consisting of non -organic debris free mineral soil of similar composition as the underlying native soils. Groundwater, if encountered, should be maintained at least 2 feet below the bottom of the excavation. The Geotechnical Engineer of Record or their designated representative should observe the project excavations to determine that unsuitable materials have been properly removed and adequate bearing support is provided by the exposed soils. The exposed soil at the base should be compacted with a vibratory roller to 95 percent standard Proctor dry density (ASTM D698). Such observations and testing should be performed prior to backfilling. The on -site non -organic soils are anticipated to be suitable for reuse if properly moisture conditioned and compacted. Replacement backfill required in utility trenches should consist of non -organic material similar to the surrounding soil. Page 2 of 14