11419 19TH AVE SE Geotech Report 2018-01-02 MF Import

,� ( � 8.0 Structural Fiil � Only rough grading plans were aclilable at the time of this rcport. We understand that the finished floor elevations will Uc approximately as sho�vn on the site plan given us and therefore, on site or � possibly imported fill will be required. All references to structural fill in this report refer to subgrade preparation, utility backfill, fill type, placement, and compaction oi materials as discussed in this section. After the soil has b�en excavated, the upper 12 inches of exposed ground to receive � structural fill should be recompacted to a mi:�imum of 90% of the modified Proctor m�imum density using ASTM:D I�57 as the standard. If the subgrade contains too much moisture, adequate I � recompaction may be difficult or impossi�'te to obtain and sliould probably not be attempted. In lieu of recompaction, the area to receive F.il should be blanketed with washed rock or quarry spalls to act as a capillary break between the new fill and the wet subgrade. � After recompaction of the exposed ground is tested and approved, or a free-draining rock course is laid, structural fill may be placeci to attain desired grades. Structural fill is defined as non-organic � soil, acceptable to the geotechnical engineer, placed in 8 inch loo�e lifts with each lift being compacted to 95%of the modiEed Proctor maximum dry density(ASTM:DI�57). Therefore, during overexcava[ion and replacement, the stockpiles should be protected so that the soil remains close to � its existing moisture content. Soils in which the amount of fine-erained material (sr,ialle: than No. 200 sieve) is greater than ' � approximately 5% (measured on the minus No. 4 sieve size) should be considered moisture- seusitive. Use of moisture-sensitive soil in the structural fill sY.ouid be limited ro favorable dry weather conditions. Consequently, if earfhwork operations will occur during the wetter times of the � year, a clean, &ee-draining gravel and/or sand should be used. Free-draining fiil consists of nen- ' organic soil with the amount of fine-grained matetial limited to 5% by weight when measured on !i � the minus No. 4 sieve &action. Most ot"the onsite soils are not considered to be free draining. � The top of the compacted fill should extend horizontally outward a minimum distance of at least 3 � feet beyond the location of their perimr.ter footings or pavement edge before sloping down at a ma�imum angle of 2H: i V (Horizontal: Vertical). ' The contractor should note that any proposed fill soils must be eva!uated by a representative of our . firm prior to their use in structural tills. This would required that w�e have a sample of the material 48 Itouse in advance [o perform a Proctor test and determine its field compac,ion standard. , A representative from our firm shculd inspect the stripped subgrade and be present on z full-time b�uis during placement of structural fill to observe the wurk and perfortn a representative number � of in-place density tests. In this way the adequacy of the earthwork may be evaivated. As filling -� progresses, any prcUlem areas may Ue corrected at tha[time. It is important to understand [hat taking � random compaction tests on a part-time basis will noi assure unifoanity or acceptable performance ofa fill. ' � S� ,� ' MAYES TESTING ENGINE�RS