729 100TH ST SE Geotech Report 2018-01-02 MF Import

� IID l. NELSON AND ASSOCIATES, INC. l ConsulNng Enginrrring Geology April 7, 1989 Pro�ect No. 3989 Dage 4 downslope along the east side of the property, and continuing at a minimum 1/2S grade to the nortF.western portion of the s1te. After excavation of the trench, a perforeted 6 inch PVC pipe should be placed along the bottom of the trench, and covered with 6 inches of pea gravel . Cleanout rlsers sAouid be � pler.ed at accessible ereas, preferabiy at the up-gradient end, and at the northMest and northeast bu11d1ng torner ereas. Backfill within the trench ebove the pee gravel should conslst of 2 lnch crushed rock (railroad ballast), compected into plece to Nithin 12 inches of the surface grade. A geotextlle should then be placed ebove the crushed rock, and structural fill placed above the geotextTle up to finish grade. Proofro111ng After dewetering drain placement, the proposed development area should be proofrolled using a vibratory drum roller with static drum weight uf at least 10,000 pounds, and a dynamic rating of at least 25,000 pounds. The compactor should be run over the erea at a slav rate for about 4 hours, end observed by this office during proofrolling. The performance of the proofrolling technlque should aid in observin9 any soft spots which may occur wlthin the exlsting fill body, and provlde some additional compaction of the existing fill meterials. Any soft spots noted should be remaved and replaced with structural f111 . Structural Fill Generol : All f111 pia�ed beneath Dulldings, pavements, or other settlement sensitive � features should be placed es structural f111. Structural fi11 , by definitlon, is placed in accordance with prescribed methods and stanAards, end is � monitored by en experienced geotech M cal professtonal or soils technicien. Field monitoring procedures would include the performance of t representative � number of 1n-place density tests to document the attalnment of the deslred degree of relative cumpact9en. r � i