10632 7TH AVE SE Geotech Report 2025-07-28

IJune 6,2008 Serenity Meadows L&A Job No. 8A017 Page 17 Building Footprint Excavation Excavation of building footprints, if encountering groundwater, should have the bottom of excavation sloped and have ditches excavated along the bases of the cut banks to intercept and IIdirect groundwater seepage to flow into a sump pit from which water can be pumped out of the pit into a temporary storage and settling pond. A layer of 2-inch crushed rock should be placed Iover firm subgrade soils under footings, as required, to protect the soils from disturbance by construction traffic. This crushed rock base should be built to a few inches above groundwater level, but not less than 6 inches thick. The crush rock base should be placed in lifts not more than 12 inches in loose state, with each lift compacted to a non-yielding state with a vibratory mechanical compactor. IRunoff over Impervious Surfaces Storm runoff over impervious surfaces,such as roofs and paved roadways and driveways,should Ibe captured by underground drain line systems connected to downspouts and by catch basins installed in paved roadways and driveways. Stormwater collected by such drain line systems I should be tightlined to routed into sediment control structures/oil-water separators before being released into the under drain of the rain gardens. Finish Grade around Buildings-11 . The finish ground, exceptpaved areas, around each buil ding�, should be graded such that surface water is directed to flow away from the buildings. We recommend that unpaved finish ground be sloped at a p gradient of three percent minimum for a distance of at least 10 feet away from each building. 1 Building Footing Drains A subdrain system should be installed around the perimeter footings of each building to minimize accumulation of groundwater under the buildings. The subdrains should consist of a 4- LIU & ASSOCIATES INC.