2211 GIBSON PL Geotech Report 2023-04-06

August 18, 2014 Gibson Bluff L&A Job No. 14-056 Page 17 loaded dump truck. Any areas with excessive weaving or flexing should be over- excavated and re-compacted or replaced with a structural fill or crushed rock placed and compacted in accordance with the recommendations provided in the STRUCTURAL FILL section of this report. We recommend that a 4-inch-thick minimum, compacted, crushed rock base (CRB), consisting of 7/8-inch-minus crushed rock, be constructed under the pavement of the road/driveways. This crushed rock base should be overlain with a 3-inch asphalt treated base (ATB) topped by a 2-inch-thick Class B asphalt concrete (AC) surficial course for the public road and overlain by a 3-inch-thick Class B asphalt concrete (AC) surficial course for private driveways. Drainage Control Building Footprint Excavation Groundwater seepage is unlikely to be encountered in building footprint excavation for the proposed residences. However, if encountered, the bottom of building footprint excavation should be sloped and ditches excavated along the bases of the cut banks to direct collected groundwater into sump pits from which water can be pumped into a nearby storm sewer inlet. A layer of 2-inch crushed rock should be placed over footing bearing subgrade soils, 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 compacted in 12-inch lifts to a non-yielding state with a vibratory mechanical compactor. LIU & ASSOCIATES, INC.