3702 TULALIP AVE 2016-01-01 MF Import

� SERS Public Saf, 9-1-1 Communication Tower • PSI Report No. 704-05224-5 December 25, 2G00 Page 6 Proctor), if density testable. Fill materials should be placed in layers that, when compacted, do not exceed about 12 inches, depending upon the type of compaction equipment used. Selected samples of the materials to be used for structural fill should be submitted to our laboratory in order to evaluate the maximum density, optimum moisture content, and suitability of the soil fur use as fill. 5.1.1 Site Preparafion During Wet Wealher Construction The on-site, silty lean clay is considered to be highly moisture sensitive and thus is not recommended for use as structural fill during wet weather construction. Additional fill material, if needed, during wet weather construction should consist of an all-weather, clean, granular fill containing less than 5 percent materiai passing the No. 200 sieve, such as sand, crushed rock, or sand and gra��el. During wet weather grading operations, all excavations should be per(ormed using a smooth-bladed, tracked backhoe working from areas where material has yet to be removed or from the already placed structural fill. Subgrade areas should be cleanly cut to firm undisturbed soil. Proofroiling of excavation botloms is likely not appropriate during wet weather grading in order lo avoid disturbance of moisture-sensitive soils. Should construction take piace during wet weather, we recommend that a representative of the geotechnical engineer be present to observe the subgrade in order to evaluate whether additional preparation is indicated. Placement of crushed rock should fol!ow immediately after site grading in order to provide protection of the se�sitive subgrade soils during construction activities. In traffic areas, the placement of a one-foot thick granular working base is generally recommended with thicker sections and/or geolextile fabrics recommended in heavily traveled areas. Generally, three to six inches of crushed rock is sufficient in foot traHic areas. 5.2 Excavations Excavation and construction operations may expose the on-site soils to inclement weather conditions. The stahili;y of exposed soils may rapidly deteriorate due to preapitation or the action of heavy or repeated construction traHic. Accordingly, foundation area excavations should be adequately protected from the elements, and from the actic i of repetitive or heavy construction loadings. 5.2.1 Construc(ion Dewatering Water seepage in excavations should be anticipated during the wet season oi the year. For rnosl of the excavations for ihis project, �umping from sumps outside the limits of the excavation shouid conlrol water seepage and surface water ponding.