2000 TOWER ST ARTS AND SCIENCES BLDG 2018-01-02 MF Import

SUBSURFACE SOIL CONDITIONS Soil Conditions Based on the soil conditions encountered in the borings, the building site is generally underlain by asphalt pavement and base course materials overlying dense to very dense glacial till with dense to very dense and very stiff to hard advance outwash deposits at depth. The soil units encountered in the borings arc described below. • Asphalt and Base Course. Asphalt and crushed base course was observed in all the borings. The asphalt section varied from 2 to 3 inches thick. The und, rlying base course section consists of crushed gravel with sand tliat ranges from 4 to 6 inches thick, but is typically 5 to 6 inches thick. • Glacial Till. Dense to very dense glacial till was observed in all of the borings under the existing pavement section. The till generally consists of gray -brown silty tine to medium sand with varying amounts of gravel. The glacial till extended to the full depth of borings B-1, B-3, and B-4, which were terminated 21 to 26 feet below the ground surface. However, the till was about 14.5 and 24 feet thick in borings B-2 and B-5, which were drilled in the cast area of the proposed building. The bottom of the till is at about Elevation 94.5 in B-2 and between elevations 88 to 92 feet in 0-5. Although not observed, cobbles and boulders are commonly encountered within the till deposits. The contact between the glacial till and the underlying advance outwash was somewhat abrupt. The observed elevations of the till deposits are summarized in Table 1. • Advance Outwash Deposits. Advance outwash deposits consisting of dense to very dense silty fine sand and very stiff to hard silt and silty clay were observed below the till in borings B-2 and B-5. These soils appear to be associated with the upper section of the mapped glacial advance outwash deposits. The top of the advance outwash was observed in B-2 at a depth of about 14.5 feet levation 94.5 feet) and in B-5 at a depth between about 20 to 24 feet (Elevation 88 to 92 feet). The observed elevation of the top of the advance outwash deposits arc summarized in Table 1. T.M. 1 Flnvaiinn of Naitvn faaciat Snils Boring FB-1 Approximate Ground Surface Elevation (feet) Glacial Till Elevation (feel) Top of Advance Outwash Elevation (feet) 114.5 93.5' to 114 Not obscrved B-2 109 94.5 to 1 88 94.5 B-3 119.5 93.5- to 119 Not observed B4 115 940 to 114 Not observed B-5 112 88-92 to 111.5 88 to 92 Bottom of the glacial till was not encountered. Groundwater Conditions There was no significant groundwater seepage observed in the borings. However, moist to wet soils were observed in borings B-1, B-2, and B-4 at depths of about 15, 23, and 20 feet, respectively. We anticipate that zones of groundwater will exist in more permeable layers within the till and outwash deposits in response to seasonal changes in precipitation. Although not observed in our borings, we also G e o E n g i r c c r 5 3 File No. 5836-002-00/040204