10200 19TH AVE SE Geotech Report 2018-01-02 MF Import

� , filt ic encountered durin .,rte radin B "� S g (such az near the southwest corner of the site), its suitability for use as stxuctural fil: should be evaluated by our field representative during construction. At the dme of our last site visit(June I1, 1993), the moisture contem of the native till soils was generally at or slighdy above the optimum moisture conten!.. We expecc that the on- site materials would generally be suitable without aeration during the late summer months. During eztended periods of�ot weather, it may be necessary to add water to properly compact � some of the soils classified as SP-SM. The giacial till is very dense at depth such that practicai refusal was encount�red during � excavation of the test pits with the CASE 580 6acl�hoe. We expecc thac upper 2'h to 5 feet � (approximate) of the weathered till can be exc;avatecl with conventional excavation equipment. '' However, large ezcavators may be needed to excavate deep trenches and it may be necessary to • use rippers to loosen the unweathered till during.mass gradiog. We recommend that all fill placed within the building area and within 2 feet of Lhe pavement subgrade be compacted to at least 95 percent of the maximum dry density as determined in accordance with ASTA4 D-1557. The stiuctural fill with this densiq• criterion for the building azea shculd extend iaterapy beyond the perimeter of the building a distance , equivalent to the height of the fill. We recommend that all structural fill placed more than 2 fee[ ' below the pavement subgrade elevation be compacted to at least 90 percent uf the same standard. - We recommend that structural fill be placed in loose layers not more than 10 inrhes thick. Each liCt should be uniformiy c;ompacted ac recommended before placing additional lihs uf fill. We recommend that the appropriate lih thickness, and the adequacy of subgrade prepazation and st:uccural fill compaction be evaluated by a field representative from our ficm during � ' construction. A sufficient number of in-place deasity tests should be perfurmed ;�s ihe fill i� t.. - being placed to determine if the required compaMion is beir.g achievzd, PERNfANENT SLOPES We recommend that temporary cut slopes in we2thered tifl and suvcturel fill soils be inclined at 1H:1 V (horizontal to vertical). Temporary cut slopes in the dense unweathered glacial till may be inclined at 'hH:1V. !f"uncontrolled" fill is encountered in cut slopes, GeoEngineers shnuld evaluated the allowable slope inclination based on the 5eld conditions encoantered. For slopes that wil! not be exposed to standing water, we recommend a maximum permanent slope inclination of 2FI:1V in the native, undisturbed soil or in structural fill placed in accordance with our recommendations. For wetted slopes, such az for wedand azeas and drainage ditches, we recommend a manimum permanent slope inclination of 3A:IV. Swctural fill placed within � ' building and pavement azeas should meet the criteria described in the previous section, fiill s6ould be carefully cc�mpacted on the slope face, or the fili embankment can be overbuilt and cut back to iu final configuration. Permanent slopes must be hydroseeded or otherwise protected from e�rosion. Temporary erosion control measures will be necessazy until permanent ve$etation is established. G e o E n � i n e e t � 6 Fk Na.0975-017-R73/062993