1988-001078 - new structure - Laserfiche WebLink

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Page Two During our full-time observations at the site , the contractor removed the poor soils from the building area and from a 12 ' oversize area beyond the perimeter building walls of the two east structures , as field staked by the project surveyor. All corner offset stakes were set. at 16 ' out from building and retained throughout the excavation activities . No space was left between the proposed structures . Instead , the soil correction for both buildings was handled on a single excavation basis . Old fill material was removed, together with a layer of organic topsoil . In the west half of the excavation, the depth of excavation was approximately 5 ' to 6 1/2 ' below original ground surface . In the central portion of the work area, the excavation started sloping downward to a maximum depth of approximately 11 ' and 13 ' in the northeast and southeast oversize corners , respectively. In the deeper excavation area, there were peat and muck soils located beneath the topsoil . Then, a layer approximately 2 ' thick and consisting of bog lime and soft gray alluvial clay was located beneath the peat and muck soils. All organic materials and a majority of alluvial clay were removed in the excavation process. Approximately 6" of clay was left in the bottom of the excavation to help minimize the amount of water entering the excavation. As the excavation work progressed, relatively clean sand materials were pushed into the excavation from a steep bank, scouring the excavation bottom as the work progressed from west to east . Along the east bank, the excavation work continued toward the south or the deeper excavation area.. Throughout this work, a maximum depth of water of about 3 ' existed . Some pumping was performed to allow direct observation of the bottom, while some bucket inspection was performed to verify the remainder of the excavation area. At the southeast corner of the excavation area the south oversize line was extended out, beyond the 16 ' identified stakes in order to provide room for the final cleanout . CONCLUSIONS AND RECOMMENDATIONS Based on our full-time observations at the site and our engineering experience , we have formulated the following conclusions and recommendations : 1 . It is our opinion that all old fill materials , topsoil , organic soils , and weaker alluvial soils have been removed from the surveyor-staked structural areas of the two buildings and from an oversize area exceeding 10 ' around the structures in the deeper fill regions.