9001 AIRPORT RD Geotech Report 2018-01-02 MF Import

i I y}�y,�rface Ezp(oration. Gto:agit Hatard. aut PrelimirwrY Ge°�ecluu�°I�gineering Repon Sno-/s!e SkIAs Center Addirion P�elimi Desi n Recammend�o"5 Everttt, Wathin ton density using ASTM:D 1557 as the standazd• oss ble t bobtain and should prob bly nocrbe adequate recompaction may be difficult or imp attempted. In lieu of recompaction, the area to receive fill should be blankeced W�t1� W�h� rock, quazry spalls, or crushed recycled concrete to act as a capillary break between the new fill and the wet subgrade. Structural fill should be placed and compacted within 2 percent of the optimum moisture content. After compaction of the exposed ground is tested and approved or a free-draining rock course is laid, possibly in conjunction with enSineering stabilization fabric, structural fill may be placed to attain desired grades. Structural fill is defined as non-organic soil, acceptable to the gcotechnical engineer, placed in maximum 12-inch loose lifts, with each lift being compacted to at least 95 percent of the modified Proctor maximum density using ASTM:D 1557 as tha standazd. The contractor should note tha� aay proposed 611 soils should be evaluated by AFSI prior to their use in fiils. This would require that we have a sample of the material 72 hours in advance co Perform a ��tor test and detemrine its field compaction standazd. Soils in which the amount of fine-grained material (smaller than the U.S. No. 200 sieve) is greater than approximately 5 percent (measured on the minus U.S. No. 4 sieve size) should be considered moisture-seasitive. Use of moisture-sensitive soils in smictural fills should be limited to favorable dry weather and near-optimum subgrade moisture conditions. 10.2 Suitabili of On-Site Soils as Swctural Fill � � The on-site lodgement tIll soils aze suitable for use as structural fill and conform to Washington State Depaztment of Transportation (WSDOT) Standazd Specificadon 9-03.14(3) °Common Borrow." Lodgement till contains significant amounts of silt and are considered moisture-sensitive. Construction equipment uaversing the site when the soils aze wet can cause considerable distutbance� If fill is placed during wet �'vea�er or if proper compaction cannot be obtained due to wet subgrade or soil conditions, a select material consisting of a clean, free-draining gravel andlor sand shouid be used. Free-draining fill consists of non- . organic soil with the amount of fine-grained material limited to 5 percent by weight when measured on the minus U.S. No. 4 sieve fraction and at least 25 percent greater than the No. 4 sieve. Silr Content of On-Site Soil - L,aboratory testing indicates that the native lodgement till contains elevated silt contents (between about 40 and 50 perceot) and, as such, do not meet WSDOT specifications fo 1 cation gravel base, ballast, gravel backfill, pipe bedding, select borrow, or any other app where relatively low silt contents aze required. Materials meeting low silt content requirements will require that they be imported from an off-site location. The results of the ASSOCUTED EAR7N S�IF1``�'�NC. June il. 2008 Page i2 pl;.ad �F.FL�801I3A'-No/c�is��1131F�1HP