1919 112TH ST SW 2016-01-01 MF Import

March 1A. 1994 10 943-]525 4.'l Field InveaHgation Our field investigation was conduded on March 8, ]994 and consisted of excavating 8 test pits (TP•1 through TP-8) on the site to a maximum depth of 14 feet. The test pits were excavated using a rubber-tired backhoe under the full-time direction of a member of our engineering staff. The test pits were located in the field by pacing from existing site landmarks. Test pit locations and ;levations were interpolated from a site plan prepared by Target Surveyors, Inc., dated April 8, 1993. Our field engineer observed and directed the test pit explorations, collected representative, but disturbed aoil samples, and recarded soil descriptions, stretigrephy, density/consistency, and groundwater data on a test pit log form. Summary logs of the test pits are presented in Appendix A. Soil samples were described using the Uni(ied Soil Class�cation System (USCS). An explanation of the classification system is included with the test pit logs. Soil samples were returned to our geotechnical laboratory for storage. The test pits were backfilled at the conclusion of sampling and observations. The backfill was tamped in place with the backhoe bucket; I�owever, some ground settlement over the test pit should be expected. 4.3 Subsurface CondiUons 4.3.1 Soil The soil conditions described here represent those conditions observed 3n our test pits. Our test pits encountered a consistent stretigraphic soil section that consisted of a layer of topsoil or forest duff, underlain by a compact to very dense till. The upper portion of the till was weathered and generally compact to dense. The lower till was unweathered and typically dense to very dense. Fill was encountered in only one test pit, TP-1, to a depth of 1.5 feet. The units are described in greater detail below. �opsoiUFore�t Duff - Thi3 unit was observed in all of our test pits and was composed of a loose, organic rich silt and sand with occasional gravel. On lot 35 (T'P-1, 2, and 3) the topsoil was only about 0.25 to 0.75 feet thick and consisted of predominantly grass. 1n ihe remaining test pits the surface contained up to one foot of organic rich, silty sand, forest duff. Fill - Test pit TP-1 was the only test pit to encounter fill. The fill consisted of dense, silty sand, IiNle grevel and was only about 1.5 feet thick The fill appeared to be reworked soil from the subject site. It is likely that other areas of fill will be encountered during construction in the vicinity of the existing house. Weathered Till - This �nit was encountered below the topso�Vforest duff and below the fill in TP-1. It was typically compact to drnse, and yeilow�sli brown in color as opposed to the olive gray color of the underlying unweathered till. The weathered till consisted of a silty sand, with little gravel, with a trace of organics. The contact belween this unit and the unweathered till was gradational. Althaugh not observed on this site, we have found that groundwater seepage is common near fhe weathered/unweathered till contact. The water infiltrates through the weathered zone and perches on the relatively impermeable, unweathered till. Our test pils did not Golder Assoclates