6920 SEAWAY BLVD Geotech Report 2018-01-02 MF Import

f �1t most locations, [he ruresc durf and fill are underlain by glacial [ill Iueposits. I.ocal deposits r: pea[ and other soft soils occur in some loalying areas. Clean outwash sand and gravel deposits are present along [he drainage � which bounds [he site to the west. The nstive glacial Cill consLsCs of silty sand with varying amoun[s of t gravel. The upper pur[ion �f the ti1L is typically loose to medium dense due Ito the effects of weathering. Thzse deposits grade from medium den5e to very dense with increasing dep[h. ISeveral bog areas werz identified during our reconnaissance af the site. The locations of the larger bog areas are shown on P1aCe L Tes[ Pits 4 and IZO were excava[ed 1n [wo of these areas and hand probings were performed in the remaining areas. The t�•pical soil pcofile in bog areas consists uf au Iupper l�yer of sof[ peat an.3 organic silt overlying Jeposits of soft inorganic silt. The inurganic silt is, in turn, underlatn by glacial till or outwasli I deposits. The soft peat and silt deposits wece generally observed [o be on the order oE 1 Co 3 feet thick, excep[ at the loc�[ions of Test Pits 4 and 20. In Test Pit 4, [he peat and silt were observed to be 8 feet thick, while in ITest Pit 20 these suils extznded to the maximum depth which could be explored by the backhoe (Ll fee[) . ICle�n outwash sand �nd gravel depusits are presen[ along the drainage to the west. Outwash deposi[s were encountered in [he Lower portion oE the Idrainage in Test Pits 22, '3 und 25. 'fhese deposits were also encountered below a cap oE glacial till in Test Pits 5 :�nd 8 on the slope ��hich bounds I the drainage co the eas�. =he ouCwash aeposits are typically medium dense tu dense. Ground waeer oUservati_ns were �.idc as the explora[ions were perfurmed. IIn addition, piezometers we:e installed in Borings l , 2 and 3 to monitor ground waLer levels followiag driiling. Ground wa[er seepage was encoun[ered Ionly in Test Pits 4 and 20 at the time Che test pits were excavated. In bo[h test pits, the seepage uccu_red Erum perched ground water zones within peat Iand silt deposits. This [y�e of seep;ige is no[ expected to be a significan[ factor during construction, �roviding that appropria[e drainage sys[ems are installed. The ground water levels in the piezometers installed in Borings L through 3 were measured on Jc[ober 12, 1983 at dep[hs ranging from L2 to ZL eeet (Elevation 599 to 607 `eet) . Yhe ground water ubserved Ln these borings appears to be perched in sa^d lenses which are distribu[ed Chroughout [he Klacial till deposi[s. It �hould be expec[ed tha[ site ground water levels wi�l fluctuate seasonally, -articularly in perched Ground wa[er zones. �\ U - '� - GeoEngineers incorporated