Agenda - Council - 04/14/2020 - Laserfiche WebLink

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Ul 20-01 Variolite Street Reconstruction Ramsey, Minnesota NTI Project No. 19. MSP09109.000 Variolite Street Northwest — Borings SB-1 through SB-57 Bituminous pavement thickness within this area ranged from approximately 1.5 to 8.0 inches at the boring locations. Apparent aggregate base thickness ranged from approximately 3.0 to 24.0 inches. As an exception, apparent aggregate base was not observed at the Boring SB-17 location. Apparent previously -placed fill soils generally consisting of poorly graded sand (SP), poorly graded sand with silt (SP-SM), silty sand (SM), and sandy lean clay (CL) were encountered to depths ranging from approximately 2.0 to 7.0 feet below the top of pavement. As exceptions, apparent previously placed fill was not observed at Boring SB-38 and Boring SB-5 terminated in fill materials at a depth of approximately 10.5 feet below the top of pavement. Organic materials and bituminous pieces were occasionally encountered within the fill materials. Native glacial deposit soils consisting of poorly graded sand to poorly graded sand with gravel (SP), poorly graded sand with silt to poorly graded sand with silt with gravel (SP-SM), silty sand (SM), and clayey sand (SC) were observed extending to the boring termination depths. Swamp deposit soils were observed at Borings SB-23, SB-24, SB-35, SB-37, SB-39 through SB-44, and SB- 46 through SB-49 consisting of silty sand (SM), poorly graded sand (SP), poorly graded sand with silt (SP- SM), sandy silt (ML), and peat (Pt). Organic contents of selected samples ranged from 2.1 to 53.7 percent with moisture contents ranging from 26 to 236 percent. Groundwater was observed in thirty-five of the fifty-seven (57) boreholes at the time of drilling. The groundwater depths ranged from approximately 2.5 to 11.5 feet below the top of pavement. The lack of observed groundwater in the remaining boring is likely due to the short duration for which the borehole remained open combined with the varying site elevations. In addition, the on -site silt laden soils have the potential to be somewhat impervious and conducive to the development of zones of perched water at varying elevations and locations across the project area. Please refer to the boring log included in the appendices. Tables 1A and 1B summarizes the encountered subsurface conditions for Variolite Street Northwest. Page 3 of 10