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Mr. Joe Green <br />Project No. EAIX-91-4%l <br />Report No. 09-121-2123 <br />December 26, t991 <br />Page 2 <br /> <br />site Description <br /> <br />The site is at street grade and flat with a s~eep bank <br />dropping to the north into deep ravine. Site is grass <br />covered with cuts made for foundations at the west and east <br />ends of the site. The top of the slope bank contains scarps <br />with displacement of at 6" which extend at 5 foot back from <br />the bank. These scarps approach within 2 feet of the west <br />pad and extend into the northeast corner of the ~ast pad. <br /> <br />subsurface Exploration <br /> <br />In order to ascertain soil conditions, 3 test borings were <br />made using a truck-mounted hollow-stem power auger. Boring <br />locations are shown in Fig. 1, attached. 'Samples were taken <br />at 2.5-ft. intervals to a depth of 15 feet, and at 5-ft. <br />intervals thereafter in conjunction with th~ Standard <br />Penetration Test. The Standard-Penetration Test is performed <br />by driving a 2-in. O.D. split-spoon sampler into. the <br />undisturbed formation at the bottom of the boring with <br />repeated blows of a 140-lb. pin-guided hammer falling 30 <br />inches. The number of blows required to drive the sampler a <br />given distance is a measure of th~ soil consistency. Samples <br />were identified in t~e field, placed in sealed containers and <br />transported to the laboratory for further classification and <br />testing. <br /> <br />Soils and. Geology <br /> <br />Soils in the project area consist of a sequence of fine- <br />grained sediments (silts and sands) found extensively <br />throughout the Wiilamette and Tualatin Valleys (Willamette <br />Silt), underlain by fine-grained soils of the Troutdale <br />Formation. The Troutdale Formation is known from other <br />subsurface information'to extend to depths of several hundred <br />feet. Specific units are described briefly as follows: <br /> <br /> <br />