1228 GRAND AVE Geotech Report 2022-10-25

April 7,2008 Mr.Don Levin L&A Job No. 8A037 Page 9 Fill embankments placed over areas steeper than 15% grade should be structurally supported. The ground over which structural fill is to be placed should be prepared in accordance with recommendations in the Site Preparation and General Grading and Excavation Slopes sections of this report. Structural fill should be placed in lifts no more than 10 inches thick in its loose state, with each lift compacted to a minimum percentage of the maximum dry density determined by ASTM D1557(Modified Proctor Method)as follows: Application %of Maximum Dry Density Within building pads of additions and garage 95% Roadway/Driveway subgrade 95%for top 3 feet and 90%below Basement/Retaining wall backfill 92% Utility trench backfill 95%for top 4 feet and 90%below BUILDING SETBACK The purpose of building setback from the top or toe or an overly steep portion of a slope is to establish a safe buffer such that if a slope failure should occur on the slope, the stability of the structure can be maintained and damages to the structure minimized. Factors affecting required setback of the new residence from the crest of adjacent steep slope include: geological constraints (such as soil and hydrological conditions) of the site, hazard from development to subject property and surrounding properties/right-of-ways, impact of construction method and technique on critical areas,mitigation of impacts on critical areas, impact of utility installation and roadway construction on geologically hazardous areas,etc. The subject site is underlain by dense silty sand and hard fine sandy silt of high shear strength with high resistance against slope failures. Therefore, geological restraints of the site which may LIU & ASSOCIATES, INC.