4704 HARBOR LN 2018-01-02 MF Import

[I APPENDIX A FIELD EXPLORATIONS The subsurface conditions were explored at the site on August 26, 27, and 28, 2009 with five geotechnical borings extending from 12.5 to 31.5 feet below the existing ground surface using a portable drill rig. Four of the borings were loci; -d near the top of the steep slope, and one boring was located in front of the house. 'three hand auger explorations were also conducted on the slope. Geologists from Nelson Geotechnical Associates, Inc. (NGA) were present during the explorations, examined the soils and geologic conditions encountered, obtained samples of the different soil types, and maintained logs of the explorations. A Standard Penetration Test (SPT) was perfonned on each of the samples during drilling to document soil density at depth. The SPT consists of driving a 2-inch outer -diameter, split -spoon sampler 18 inches using a 140-pound hanuner with a drop of 30 inches. The number of blows required to drive the sampler the final 12 inches is referred to as the " N" value and is presented on the boring logs. The N value is used to evaluate the strength and density of the soil deposit. The soils were visually classified in general accordance with the Unified Soil Classification System, presented as Figure A-l. The logs of the borings and hand augers, edited to reflect examination of soil selected samples chosen for laboratory analyses, are presented in Figures A-2 through A-7. A general description of the subsurface conditions encountered in the borings and hand augers has been provided in the body of the report, under the Subsurface Conditions subsection. NELSON GEOTECHNICAL ASSOCIATES, INC. 3 ca