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I I I I I I I I I I I I I I I I I I I Simons, Li and Associates, Inc. Job. No. 6l43J002 Project: Portland Flume Reconstruction saturated. It is recommended that foundation excavations into undisturbed soils be inspected by the geotechnical engineer and deepened if loose or disturbed soils are encountered. If the soil conditions encountered are significantly different than those presented in this report, this firm should be contacted for verification and/or supplemental recommendations. Site preparation: It is anticipated that excavation into the near surface soils should be possible with conventional excava- tion equipment. Excavation into areas with dense cobbles may possibly require heavy-duty, track-mounted excavation equipment with single-tooth rippers. Large boulders and ~andstone bed- rock will probably require overexcavation or the use of pneu- matic operated jack-hammers or drills to facilitate rock break- up and removal. Since the material is a highly variable con- glomerate, maximum particle size and percentage will vary con- siderably along the alignment of the flume. In general, maxi- mum particle size will increase toward the top of the flume. The largest boulder size encountered in the test pits was 2 feet, but even larger sizes may be encountered during construc- tion. Because the test pits were not excavated exactly on the alignment, some lenses or massive areas of underlying bedrock besides that observed in Test pit No.6 may be encountered, probably near the top of the flume. It should be anticipated that shoring of excavation side slopes will be required along some portions of the alignment. Areas of coarse granular material will require temporary lateral sup- port as will areas where subsurface seepage is encountered. Groundwater was not encountered in the test pits, however, subsurface seepage may occur throughout the alignment and may vary depending on the time of year that construction takes place. -4-