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i , <br /> , <br /> with a full depth basement is feasible on.this lot, based on location of the persistent ground water <br /> level (at about a 13 feet depth in the Borings). Finally, perimeter drain lines must be installed along <br /> ' the foundations to remove potential transient water flow through the oxidized zone. <br /> Ground water may be encountered in excavations fo� foundations, floor slabs, sewer and utility <br /> trenches, or other excavations. If ground water is encountered, the excavation must be kept dry by <br /> dewatering. Excavation in poor-draining cohesive soil (silty and clayey) may encounter minor <br /> ground water seepage. Either pumped sumps or gravity-flow drainage trenches can be considered <br /> for dewatering. <br /> To prevent movement of bulk water and capillary moisture into the building a waterproofing system <br /> rrtust be provided. This system is discussed in the WATERPROOFING section of this report. <br /> GROUND <br /> • Natural topsoil encountered in the upper 1 foot of Borings 1 and 2 contains organic matter. <br /> This is an unsuitable material that should not remain beneath the buiiding. The important issue <br /> with significant amounts of organic matter in soil is that it can potentially decay during the life of <br /> the building, especially when exposed to oxygen (air) and bacteria. Bacteria cause decay of <br /> the organic matter, leaving voids in the soil; voids may eventually collapse by ground weight <br /> causing slow ground surtace settlement. <br /> • Natural Horizon B soil encountered in Boring 2 is a suitable material to remain beneath the <br /> building. Glacial Outwash encountered in Boring 1 is a suitable material to remain beneath the <br /> building. It is medium dense in its natural grain packing. <br /> • Supraglacial Till encountered in Borings 1 and 2 is suitable to remain beneath the building. It is <br /> predominantly stiff in its shearing strength. The supraglacial till has an allowable soil bearing <br /> pressure of about 3000 pounds per square foot (psfl. <br /> BUILDING SUPPORT <br /> Shallow-depth foundations can be used to support the building. Building foundation bearing <br /> grades are anticipated to be designated in Horizon B soil, glacial outwash or supraglacial till. All <br /> unsuitable and unreiiable soil must be corrected beneath foundations and ground floors. CoRect <br /> all soil that is very loose to loose, seft to firm, with excessive moisture or is otherwise unsuitable <br /> and unreliable to support the building. Remove (over-excavate) ali unsuitable and unreiiable soil <br /> beneath building foundations and ground floors according to the OVER-EXCAVATION AND <br /> STRUCTURAL BACKFILL section of this report. Replace over-excavated soil with structural <br /> backfill up to foundations and ground floors. Prepare foundation ground support as follows: <br /> FOUNDATION SUPPORTED ON NATURAL GROUND <br /> For continuous (strip-shaped) foundations up to 2 feet wide and isolated (square-shaped) <br /> foundations up to 7 feet wide bearing on stiff Horizon B soil, medium dense glacial oufinrash, or stiff <br /> supraglacial till, vibro-compact all foundation bearing grade surfaces. Make several passes to <br /> Allied Projed 05039 6 July 31, 2005 <br />