10200 25TH AVE SE Geotech Report 2018-01-02 MF Import

� � Propased Modernization and Addiriais m Su6surjace Explorution, Geolagic Hazardr, Eisenhower Middle Schoo! and Geoterhnical Engineering Repon Everett, Washrnqton Design Recommendatians placement of an engineering stabilization fabric may be necessary to prevent contaminatio� of the free-draining layer by siit migratioa from below. Afrer recompaction of the exposed ground is tested and approved, or a free-draining rock II course is laid, structural fill may be placed to attain desired grades. Structural fill is defined as non-organic soil, acceptaLle to the geotechnical engineer, placed in maximum 8-inch loose lifts with each lift being compacted to 95 percent of the modified Proctor maximum density using ASTM:D 1557 as the standard. In the case of roadway and utiliry trench fi]]ing, the backfill should be placed and compacted in accordance with current local or county r.odes and standards. The top o� the compacted fill should extend horizontally outward a minimum distance of 3 feet beyor.� the location of the perimeter footings or roadway edge before sloping down a�. an angle of 2E�:1 V. The contractor �hould note that an� proposed fill soils must be evaluated by Associated Earth Sciences, Inc. (AESI) prior to the:r use in fills. This would require that we have � sample of the material 72 hours in advance of filling activities ro perfr,r: i a Prector test and determine its field compaction standard. Soils in which the amount of fine-grained material (smailer than the No. 200 sieve) is greater than approxirnately 5 percent (measured on the minus No. 4 sieve size) should be considered moisture-sensitive. The till soils encountered on-site generally contained substantial amo�nts of silt and are considered highly moisture-sensi:ive. These materials ;,re acceptable for use as fill provided they are placed and compacted at a moisture conrent tha[ allows for the minimum specified compaction presented in this report. Reuse of till soils during wet site or weather conr!itions is expected to be difficult or impossible due to high silt content and moisture sensitiviry. Use ;�f moisture-sensitive soil in structural fills should be limited to favorable dry weathzr conditions. A portion of the existing fill soil on-site was observed to have ele��ated moisture content and is not considere�� suitable for use ir, structural fill applications. Free-draining fill can be used in wetter site and weather conditions under a wider range of moisture conditions than the on-sire soils. Free-draining fill consists of r.on-organic soil with the amount of fine-grained materiaf limited to 5 percent by weight when measured on the minus Nc. 4 sieve fraction and containing at least 25 percent greater than the No. 4 sieve. In dry weather, in-organic oR-si[e soils czr be used as s[rucmral fill if they are cleaned of woody debris and oversized rocks. We recommend that durine construction, traffic across e;cposed si�e soils should be kept to a minimum during and after storm events, until the surface drains. When these marerials are wet, it may result in disturbance of the otherwise firm stratum, requiring removal and replacemer,t of dis[urbed soils. If wet wea[her construction is expected, construction access and stagin�� areas should b�: protecred as described in the Site Preparnriai section of this repor[. Jmumrv 2j, 300d ,iSSOC1.ITED�iRTH SCIE:vCES, INC. / .tlAld-KECJ7J3a i-pru�enrCb717J9:A'E�.teP- R:A' Pa�Te 13 /{U