4003 NASSAU PL 2016-01-01 MF Import

� , Geqtechnical Engincering Report Kvemmo Single-Family Residence ' 4003 Nassau Place, Everctt September 17, 20G2 NGA File No. 356102 Page 4 1 detailed description cf the site soils, the boring logs should be reviewed. � Fill material consisting of moist silty sand with gravel and organics was encountered in Boring 1 to a � depth of 6 feet. Fill material concisting of inedium dense/ medium stiff silty sand interbedded with silt and organics was encountered in Boring 3 to a depth of 5 feet. Boring 2 encountercd medium stiff to stiff ', silt with fine sand to a depth of 8 feet. This materiel wes interpreted as weathered outwash/transitional beds. ' Below the fill and the weathercd horizon, all of our three explorations encountercd'moist, very stiff to hard gray silt that extended to the depth explored, 31.5 feet. We interpreted the silt to be transitional bed material. The subsurface conditions within the site were previously explored on May 26, 1987 by excavating 6 test piu to depths of 6 to 14 feet bel�w the existing ground surface. These explorations encountered 1 W 11 feet of fill material consisting of loose, moist to wet, silry soils with organics and occasional logs. The material underlying the fill consisud of inedium dense to densc silry sand with varying amounts of grevel. It is our understanding that the site has not been significantly graded sina that time. �� We encountered ground water in B-1 a�id B-2 immediately above the silt materisl at about 5 to 6 feet in depth. In B-3, wet soil conditions were observed above the silt material, encountered at a depth of approxin�ately I8 feet. We interpreud this ground water to be perched water. Perched gound water occurs when surface water infiltrates through more pertneable, near-surfhce soils, and is impeded by less permeable soils at depth. The amounts of perched ground water tend to ;�ary depending upon the amount of recharge. We would expect that perched ground water would be more prevalent during the wetter times of the year. SENSITIVE AREA EVALUATION Seismic Hazard The site is located within Zone 3 of the Seismic Zone Map shown as Figure 16-2 of the 1997 Unifortn Building Code (UBC). This corresponds to a Seismic Zone Factor, Z, of 030. The underlying very still NELSON GEOTL"CHNICAL ASSOC/ATES, INC. �28'