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n t IF 041, il if .. , ........... --------------- ' ea'� Oslo Road Improvement Project Page 6 File No. 11 -5420 The seasonal high groundwater level is affected by a number of factors . The drainage characteristics of the soils , the land surface elevation , relief points such as drainage ditches , lakes , rivers , swamp areas , etc . , and distance to relief points are some of the more important factors influencing the seasonal high groundwater level . When estimating the normal seasonal high groundwater table level (s) , consideration was given to the fact that the soil borings were performed during a period of drought . Based on our interpretation of the site conditions using the boring logs and the Soil Survey, we preliminarily estimate the normal seasonal high groundwater level at the site to be somewhat higher than the groundwater levels encountered at the time of our field exploration , assuming that the existing site drainage is maintained . Our estimates are presented on the Soil Boring Profiles on Figures 4 and 5 . We note that if site drainage conditions are altered from those at the time of our borings , our estimates may not be valid . If requested , Ardaman can verify the plotting of the estimated seasonal high groundwater levels on the roadway cross sections . Also , we can verify that the bottom of the proposed base material elevation has proper separation from the seasonal high groundwater elevation , or make recommendations for special base treatment in deficient areas. We note that groundwater may also temporarily "perch" atop the shallow clayey soils at depths above the estimated normal seasonal high groundwater level , during or immediately following periods of heavy or prolonged rainfall . 4.5 Construction Considerations Roadway construction should be performed in accordance with the appropriate sections of the current edition of the Florida Department of Transportation ( FDOT) Standard Specifications for Road and Bridge Construction . In accordance with these specifications, the removal of any organic materials (A-8 soils) including topsoil as encountered , and any plastic (A-2 -6) soil should be accomplished in accordance with FDOT Standard Index 500 unless otherwise indicated on the plans. Backfill should generally consist of select material (A-3 and A-24) compacted in accordance with Section 120-9 of the Standard Specifications . In-place density tests should be performed on the fill soils to verify the specified degree of compaction . The minimum density test frequency should be in accordance with the FDOT Materials , Sampling , Testing , and Reporting Guide . Fill Placement and Side Slopes for Embankment Construction are presented in the FDOT Standard Index 505 . As mentioned above , A-21,w4 type soils will likely be encountered along much of the alignment within the upper 5 feet . The A-24 type soils can be used for roadway construction using strict moisture control (in - place moisture near optimum moisture content as determined by the Proctor test) . Special compaction equipment ( i . e . , sheepsfoot-type rollers , etc.) and allowing time forthe material to dry sufficiently may also be needed to use these soils in construction . If A-2-4 soils excavated from below the groundwater table are to be used for embankment fill, we recommend stockpiling the excavated clayey/silty soils as high as possible so as to increase the rate of drainage . Prior to their use , the soils should be spread out and disced to further reduce moisture levels. Nevertheless, soil with high percentage of fines will be slow in draining and may present problems during compaction efforts . ,:. Or VI IV V LJ IjV ir 3 :"'` . . ' k` f ''kz . . u , .. _ ' . . . _ . w , , . .u,, :t : ,. _ z. .. _