3003 W CASINO RD BLDG 40-23 Geotech Report 2025-01-22

and in building areas (including utility trench backfill) should be compacted to at least 95 percent of the maximum dry density (MDD) estimated in general accordance with ASTM D 1557. 5A.3.Temporary Slopes and Excavations Temporary slopes and excavations must conform to the provisions of Title 296 Washington Administrative Code (WAC), Part N, "Excavation, Trenching and Shoring." We recommend that temporary cut slopes be constructed at 1H:1V. Flatter slopes may be necessary if seepage is present on the face of the out slopes or if localized sloughing occurs. Steeper slopes up to 3/aH:1V may be feasible in the very dense glacial till soils, provided the geotechnical engineer confirms soil conditions are consistent and evaluates the stability of the slopes during construction. Neat cuts in the native glacial till soils are feasible for shallow foundation elements. For open cuts at the site, we recommend that: im No traffic, construction equipment, stockpiles or building supplies be allowed at the top of the cut slopes within a distance of at least 5 feet from the top of the cut; Exposed soil along the slope be protected from surface erosion by using waterproof tarps or plastic sheeting; Construction activities be scheduled so that the length of time the temporary cut is left open is reduced to the extent practicable; is Erosion control measures be implemented as appropriate such that runoff from the site is reduced to the extent practicable; Surface water be diverted away from the slope; and in The general condition of the slopes be observed periodically by the geotechnical engineer to confirm adequate stability. Because the contractor has control of the construction operations, the contractor should be made responsible for the stability of cut slopes, as well as the safety of the excavations. Shoring and temporary slopes must conform to applicable local, state and federal safety regulations. We have prepared this report for the exclusive use of The Boeing Company and members of the design team for the proposed 777X Horizontal Build Line (HBL) Expansion project located within the 40-23 Building at the Boeing Everett Factory in Everett, Washington. The data and report should be provided to prospective contractors for their bidding or estimating purposes, but our report, conclusions and interpretations should not be construed as a warranty of the subsurface conditions. Within the limitations of scope, schedule and budget, our services have been executed in accordance with generally accepted practices in the field of geotechnical engineering in this area at the time this report was prepared. No warranty or other conditions, express or implied, should be understood. Any electronic form, facsimile or hard copy of the original document (email, text, table and/or figure), if provided, and any attachments are only a copy of the original document. The original document is stored by GeoEngineers, Inc. and will serve as the official document of record. Please refer to Appendix E for additional information pertaining to use of this report. GEOENGINEER .tune 15, 2022 , Page 7 File No. 0!24-294-92