2130 116TH ST SE Geotech Report 2018-01-02 MF Import

C'� H H b D�PC G� M �Hfn y�h�-i � H 7�0 �H� V1 N �Q�O �-yi ��g rjJV C] t"y� HH gy H C) � !/� � H (/� HOtn � CA�CADE GECTECHNICP.L Apiil 3, 1941 Bill �raber Job No. 9103-07G Paqe � The soils ok�served in the tesY pits generally consisted of uncontrolled fill overlyinq weathered and unweathered glacial till. Approximately s:ix (6) inches to four (4) Peet of uncontrolled fill wae observed in our teet pits. The uncontrolled fill yenerally consisted of a black silty sand with some gravel, that was rich in organic material with some construction deUris and qarbage. It was loose and wet. The native soil obcerved below tne uncontrolled fill consisted of a tan to gtay eilt�� sand with some gravel that was medium dense to 3ense, moi>t to wet and sliyhtly mottled. The upper six (6) inches of the native silty sand were mottled indicating a Iluctuating water table. Moderate to heavy seepage was observed in two of o�r test pits along the contact of the uncontrolled fiil and the u�derlying silty sand. The ground water observed in our test pits appear. to be perched on the till. Minor caving was observed in the uncontrolled fill sectio,� of our test pits. CUNCLUSZONS AND RECOMMENDTTIUNS The uncontrolled fill and oryanic soils found on-site above the native silty sand aze not suitable for the support of structural luads and slab-on-grade floors, as unacceptable differential settlement may o�cur. Structural loads and slab-on-grade flo�rs should be placed directly on the native medium dense to dense silty sand with eome qravel or on suitably compacted structural fill which is in turn frunded on the native bearing soil (till). A spread footinq foundatior placed on the native medium dense to dense, tan to qra�� silty sand with some gravel would be suitable for supportinq design loads up to 2000 psf maximum saPe bearing value if the soil is undisturhed, free of organic material, and