1600 W MARINE VIEW DR 2016-01-01 MF Import

1 ' I� , , 1 1 APPENDIX A FIELD INVESTIGATION Subsurface conditions were explorr� on April 11 and 12, 1996, under the fiill-time observation of a HWA engineer. The exploration work consisted of d�illing and sempling two exploratory borings (BH-1 and BH-2) at selected locadons within the project area. The borings were advanced to depths ranging from about 61'h to 66'h feet bdow tl►e eacisting ground surface. The borings were locatai appro�timately in the Seld by taping distances from established site feadires and plotted on the Site Plan (Figure 2). A legend to the terms and symbols used on the boring logs is presented on Figure A-1. Summary logs of the exploratory borings are presented on Figures A-2 through A-5. ' Geotechnical drilling was performed by Gregory Drilling, Inc. of Redmond, Washington under subcontract to HWA. The exploratory borings wero drilled with a truck-mounted, CME 85 drill rig equipped with a trip-release mechanism for performing Standard ' Penetration Tests (SPT). The upper 20 feet of each boring was advanced using 6'h-inch diart►eter, continuous flight hollow stem sugers. Beyond the upper 20 feet, the borings ' were advanced using mud rotary techniques. The mud rotary set-up included a 4inch inside diameter steel casing advancer with a tri-cone bit. Upon completion of drilW�g, tl� ' borings wero backSlled with cuttings and bentonite chips. Explorations located in areas of existing pavement were repaired using a quick-setting wncrete patch. , As stated above, the hammer used to perfortn SPT sampling was equipped with an automatic trip-release mechanism, which generally delivers a higher energy than a "standard" hammer equipped with a rope and cathead mechanism. Based on previ�us ' studies (Skempton, 1986), a 79 percent energy ratio should be used in interpreting the recorded SPT blow-counts obtained with a trip hammer, instead of the 60 percent atergy ratio for a safety hammer with a rope and cathead system. As such, N-values measured ' with the automatic trip-release hammer should be multiplied by about 1.3 to convert them to "standard" SPT N-values (N�). 1 t 1 t 1 At each boring location, SPT sampling was perfortned in general acc;ordance with ASTM D 1586, using a 2-inch outside diameter split-spoon sampler and a 140-pound hammer. During the test, samples were obtained by driving the sampler I8 inches into the soil with a hammer free-falling 30 inches. The number of blows required for each 6 inches of penetration was recorded. The Standard Penetration Resistance ("N-value") of the soil was calculated as the number of blows required for the final 12 inches of peneuation. If a total of 50 blows was recorded within a single 6 inch interval, the test was temtinated, and v6ozat�.nac A-1 HoNa WFsr � Assoct�'rEs, Wc.