1031 51ST PL SW Geotech Report 2023-06-23

9.6 GEOTEXTILES 9.6.1 Separation and Drainage Geotextile We recommend using a non-woven geotextile drainage material around subsurface drains to separate drain rock from adjacent materials. The geotextile should conform to the specifications for non-woven separation material provided in WSS 9-33.2(1)-Geotextile Properties, Table 3 Geotextile for Separation or Soil Stabilization, similar to Mirafi 160N. • 10.0 OBSERVATION OF CONSTRUCTION Recommendations provided in this report assume that GeoDesign will be retained to provide geotechnical consultation and observation services during construction. Satisfactory earthwork and foundation performance depends to a large degree on the quality of construction. Subsurface conditions observed during construction should be compared with those encountered during the subsurface explorations. Recognition of changed conditions requires experience with the site conditions and an understanding of the geotechnical recommendations; therefore, GeoDesign personnel should visit the site with sufficient frequency to detect whether subsurface conditions change significantly from those anticipated and to verify that the work is completed in accordance with the construction drawings and specifications. Sufficient observation of the contractor's activities is a key part of determining that the work is completed in accordance with the construction drawings, project specifications, and our recommendations. We recommend that GeoDesign be retained to observe all earthwork activities, including the following: • Excavation activities • Subgrade preparation prior to fill placement or foundation construction • Verification of foundation subgrades • Placement and compaction of fill, including fill placed in utility trenches and around buried structures • Laboratory compaction and field moisture-density tests 11.0 LIMITATIONS We have prepared this report for use by NW Homefinders, Inc. and the design and construction team for the proposed development. The data and report can be used for bidding or estimating purposes, but our report, conclusions, and interpretations should not be construed as warranty of the subsurface conditions and are not applicable to other sites. Explorationobservationsindicatesoil conditions only atspecific locations and only to the depths penetrated. They do not necessarily reflect soil strata or water level variations that may exist between exploration locations. If subsurface conditions differing from those described are noted during excavation and construction, re-evaluation will be necessary. G EODESIGN3 14 NWHnme-1-fl1 1(1161 R