11830 19TH AVE SE 2016-01-01 MF Import

Seahorse Restaurant W-5583 18 March 1988 Page 7 tests. In this way, the adequacy of earthwork may be evaluated as grading progresses. The suitability of soils for structural fill use depends primarily on the gradation and moisture content of the soil when it is placed. As the fines content (that soil fraction passing the U.S. No. 200 sieve) increases, soil becomes increasingly sensitive to small changes and adequate compaction becomes more difficult or impossible to achieve. Silty soils containing more than about 5 percent fines by weight, such as the site soils encountered in our test pits, cannot be . consistently compacted to a firm, non-yielding condition wheri the moisture content �• is more than about 2 or 3 percent above optimum. The use of "clean", granular import fill soil would therefore be necessary for fill use to complete wet weather site work. Clean granular fill should consist of well-graded sand or sand and gravel containing less than 5 percent fines based on She fraction passing the U.S. No. 4 sieve. Existing topsoil at the site is not considered suitable for structural fill , application but could be stockpiled for later use in landscape areas. Depending on the site grades, the non-organic near-surface site soils that would he available for fill would be primarily silty sands with variable amounts of gravel . These silty soils would be difficult or impossible to use as structural fill except during drier sumner months when the moisture content may be carefully controlled by aeration and drying. Even during the summer, delays in grading may occur due to precipitation or the presence of surface or ground water. If inclement weather occurs, the upper wetted portion af the fill may need to be scarified and allowed to dry prior to further earth work. If it is not practical to dry the wet, silty soils, it may be necessary to remove the upper silty sails and replace them with clean, granular fill to accommodate wet site conditions. Soils used for structural � fill should contain na particle greater than 6 inches and be free of organics and ' other deleterious materials.