2621 ROCKEFELLER AVE Geotech Report 2022-10-25

11 11 samples were selected for laboratory testing consisting of determination of moisture content and grain size distribution. A description of the laboratory testing and the test results are presented in IIAppendix B. i SITE CONDITIONS SURFACE CONDITIONS 11 The site is currently occupied by five existing residences. Additional residences exist adjacent to the north and south sides of the site. Existing site improvements associated with the residences include fences, sidewalks, and gravel parking areas adjacent to the alley on the east side of the site. The 11 topography of the site slopes gently down from about Elevation 118 feet along Rockefeller Avenue on the west to about Elevation 110 feet along the alley to the east. The locations of surrounding site features with respect to the proposed improvements are shown on the Site Plan,Figure 2. Vegetation on 11 the site includes trees, shrubs, landscaping, and grass. Utilities on site include underground sewer, water,and gas and above-ground power and communications. GEOLOGY Geologic information for the project area (Minard, 1985) indicates that native surficial soils at the site are composed of glacial till underlain by advance outwash deposits. Glacial till commonly consists of a 11 very compact,poorly sorted, non-stratified mixture of clay, silt, sand, gravel and cobbles. Glacial till commonly appears gray or blue on a fresh surface, while weathered glacial till may be brown to yellow in color. Till may include cobbles and large boulders. Advance outwash deposits underlie the glacial till and typically consist of mostly clean, pebbly sand with gravel. However, fine-grained sand and silt are common in the lower parts of the outwash and 1 sparingly in the upper part on the unit. SUBSURFACE CONDITIONS 1 Based on the explorations performed at the site, the subsurface conditions generally consist of topsoil and fill overlying dense to very dense glacial till and advance outwash. 11 We observed 3 to 4 feet of loose to medium dense silty sand with variable gravel content. This material includes fill and native weathered till. Dense to very dense glacial till was encountered at depths of 3 to 4 feet and extended to the depths explored, except in test pit TP-3. We encountered dense advance outwash sand below the till at a depth of 5 feet in TP-3 and the outwash extended to the depth explored. Table 1 summarizes the elevations of the dense to very dense glacial till encountered in our explorations. I ... I -, File No.12547-001-00 Page 2 GEOENGINEERS/ February 3,2006