7000 HARDESON RD 2018-01-02 MF Import

Quadrant 6-917-10200 12 April 1996 PON 3 prior to 1989. Based upon the density of the fill encountered within the upper 10 to 15 feet at this location, the sediment appears to have been covered with at least 10 feet of compacted fill. The relic sediment samples obtained from the borings eomisted p.interity arf yrariatar fin intermixed with silt. 3.3 Groundwater Regional groundwater is located approximately 80 feet below the current rough graded site elevation. Assumed groundwater gradient is to the north. Perched groundwater was encountered in areas of the site underlain by soft silty fill and settling pond sediments. Perched groundwater generally occurs when the downward percolation of groundwater is inhibited by a low -permeability layer. Glacial till fill encountered at the site can frequently contain perched water. Groundwater conditions should be expected to fluctuate throughout the year due to season, precipitation, site utilization, as well as other on- and off -site factors. 4.0 CONCLUSIONS AND RECOMMENDATIONS The site evaluated for this study is the proposed location for a one-story with mezzanine tilt -up concrete building with a heavily loaded slab -on -grade floor. Based on the subsurface conditions we encountered at this site, the proposed development is feasible from a geotechnical standpoint utilizing shallow foundations and slab -on -grade floor support. Areas of the maintenance building pad underlain by relic settling pond sediments should be preloaded as described in the following report sections. Owing to the silt content of the upper site soils, construction should be completed during periods of sustained dry weather, if possible. The following sections of this report detail our specific recommendations relative to site preparation, structural fill placement, foundation design, and pavement thickness design. 4.1 Site Preparation Due to the silt content and moisture sensitive nature of the on site soils, earthwork attempted during wet seasons may be difficult or impossible. Prior to site grading, any site surface runoff and groundwater seepage should be collected and routed away to a proper drainage to facilitate earthwork and future foundation and pavement construction. Prior to "structural fill" placement, we recommend that areas which are at subgrade level or which will receive fill, be scarified to a depth of six inches. The ground should then be prerolled and compacted with a roller or other suitable heavy equipment to a firm and non -yielding condition in order to achieve a minimum compacted level of at least 90 percent density (ASTM:D 1557). The upper foot of subgrade soils in pavement subgrade areas should be compacted to at least 95 percent of the ASTM:D 1557 maximum dry density value. To minimize delays during earthwork, we suggest that the contractor provide bulk samples (approximately 24 Ibs) of all soils which will be used for structural fill. In this way, laboratory Proctor tests may be performed before placement of structural fill proceeds. Due to the silty nature of the site soils, prerolling and adequate compaction can only be achieved when the soils are at or near their optimum moisture content. Any soft, wet, or significantly organic areas