7425 HARDESON RD BASE FILE 2016-01-01 MF Import

� , � GEOTECHNICAL ENGINEERING STUDY Trace and Associates July 19, 2005 � Subsurface � � � � � r- � � � � � � � � � � E-1 7 880 Page �t Subsurface conditions at the site were evaluated by excavating six test pits within the proposed improvement areas. The test pits were excavated to a maximum depth ot 14.5 feet below existing grade using a rubber-tired backhoe. The approximate locations of the test pits are shown on Test Pit Location Plan, Plate 2. The :est pit logs are include� as Plates A2 through A7. A description of the field exploration methods is included in Appe:idix A. The following is a generalized description of the subsurface conditions encountered at our test pit locations. At our test pit locations we encountered existing fiil to the maximum exploration depth. 7he existing fill consisted primarily of loose to medium dense silty sand with varying amounts of gravel (Unified Soil Classification SM) and localized layers of sandy silt and medium dense to dense soil. In Test Pits TP-3, TP-4, and TP-6 we encountered pockets of organic debris comprised of moderately to highly decomposed wood debris. Groundwater Light groundwater seepage was encountered at 6 feet below grade in Test Pit TP-6 at the time of our exploration (June 20051. In addition, we encountered increased soil moisture starting at approximatefy 8 feet below grade in Test Pit TP-3 and at 9 feet below grade in Test Pit TP-6. The observed seepage and increased soii moisture are likely indicative of perched groundwater. Dependi:�g on the time of year the grading is conducted and the depth of the excavations, local�zed zones of groundwater seepage may be encounterEd in the vault or deep utility excavations. The contractor should be aware tliat groundwater levels are not static. There will likely be iluctuations in the levels depenJing on tha season, amount of rainfall, surface water runoff, and other factors. Generally, the water level is higher and seepage rates are greater in the wetter, winter months (typically October through May). ranh Consultanls. Inc.