11632 EVERGREEN WAY BASE FILE 2018-01-01 MF Import

Pmposed Retail Develapment J-1443 112�'Street and Hwy.99 February 26,2004 { Everett,Washington PaB� 14 i l � owner. We recommend that a qualified geotechnical engineer be present during the placement of I shuctural till to observe the work and perfo�tn a representative number of in-place density tests. i In this way,the adequacy of eatthwork may be evaluated as grading progresses. � The suitability of soils used for structural fill depends primarily on the gradation snd � moisture content of the soit when it is placed. As the fines content(that portion passing the U.S. ! No. 200 sicvc) of a soil increases, it becomes increesingly sensitive to small changes in moisture I content and adequate compaction becomes more difficult or impossible ?o achieve. Soils containing more than about 5 percent Snes by weight, such as the soils encountered at ihe site, cannot be consistently compacted to the recommended degree when the moisture content is more than about 2 percent abovc or helow opNmum. Drying of the site soils may only be accomplished during favorable dry weather by methods such as scarifying and windrowing. If inclement weather or soil moisture content prevent the use of on-site or non-selcct material as structural fill, we recommend that use of "selecP' granular fill be consideced. It should be noted that the placement of shuctura! fill is in many cases weather-dependent and delays due to inclement weather are common even when using"selecP'granular fill. When moisture conditioning of the soils is required to increase the moisture content of dry-of-optimum soils, we recommend that the soils be uniformly blended with the added moisture to provide a uniform moisture content throughout the affected soils. On-site native soils may be reused as structural fill for foundation, iloor slab, and � pavement support, provided the soil does not contain significant organics or other deleterious materials and is placed and compacted at a suitable moistwe content. The soils must be placed within a relatively narrow range of the optimum moisture content (f2 percent) for proper compaction. Some drying of on-site soils may be necessary at the time of earthwork and the feasihility of gtading with on-s:te soils will depend on whether adequate drying time occurs. Typically, drying is di�cult or impossible during cold and wet winter and spring months. Recompaction problems should be cxpected in wet weather, or after thawing of frozen soils, due to the moisture sensitiviry of the soil. Reusing wet on-site soils for structural fill durin�periods when aeration and drying is not fcasible would necessitate chemical treatment of the soils to provide a working moisture content for compaction. In the summer, air-drying is commonly incorporated. When air drying is not fcasible, kiln dust admixtures are typically used to increase the workability of the wet soils to a level where the soils can be compacted. The admixtums are extremely alkaline and can increase tUe pH of the soil mixture. Before such admixtures aze considered, we recommend that their � proposed usc be submitted to the appropriate overseeing agency. Excess soils may require stockpiling for extended periods of time before they can be used. It is recommended that all stockpiled soils intended for reuse as structural fill be protected with anchored polycthylene sheet plastic strong enough to withstand local wind condidons. � i 7-1443,022604 I'i j