1228 GRAND AVE Geotech Report 2022-10-25

April 7,2008 Mr.Don Levin L&A Job No.8A037 Page 4 redeposit to a flatter inclination. The underlying fresh advance outwash deposits in their native, undisturbed state can provide good foundation support with little settlement expected for light to moderate residential structures. SOIL CONDITIONS We were the geotechnical engineer of record for a new duplex building project recently constructed on the Reference Site, about one block north of the subject residence site. We provided geotechnical engineering and construction inspection services, and verified footing bearing soils and evaluate cut bank stability of footprint excavation for the Reference Project. The building footprint on the Reference Site was cut down to about 7 feet deep. The soil conditions exposed on the cut banks were composed of 10 to 12 inches of dark-brown, loose, organic topsoil, underlain by 3 to 4 feet of light-brown, dense,fine to medium sand with a trace of gravel. This sand layer was underlain by a deposit of gray, hard, fine sandy silt. A steel T-bar manually pushed into footing bearing soils at bottom of excavation could penetrate no more than an inch. The cut banks of the building footprint excavation had stood very stable without any signs of raveling or sloughing. We expect the soil conditions at the subject residence site to be similar to those at the Reference Site. GROUNDWATER CONDITIONS A very minor trickle of groundwater seepage (less than 0.25 gpm)out of the cut was observed on September 5, 2007, at the southeast corner of the building footprint excavation on the Reference Site. This seeping groundwater was perching on top of the underlying fine sandy silt deposit which was of extremely low permeability. LIU & ASSOCIATES, INC.