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FML, Inc. STS Project 93589 August 28, 1985 -11- 1 As indicated on the boring logs, the fill deposits are highly ' I variable in both soil type and relatively density. Much of the fill was dark brown to black and contained traces of organic soil ' and debris. At the locations of Borings 9 and-15, significant amounts of organic silt or fibrous peat were encountered. 1 In general, the soils within the existing fill area are unsuitable for the support of structures, bituminous roadway^ or utilities unless some remedial actions are taken. Conditions in the area of the proposed building location would be suitable for the use of alternative subgrade corrections such as dynamic compaction "pounding", but the cost of this process including mobilization of equipment, engineering, and testing for an area of this small'size would be comparable to that of conventional site preparations. Therefore, we recommend that a conventional approach of excavation and backfilling be used in preparing this building pad. Due to the variability of soil conditions in the fill area, the full extent and nature of the required corrections may be unknown until the time of construction. The two anticipated four-plex structures located at the north end of the site are in the area of Borings 4, 5 and 10 which indicate fill extending to depths of 15 ft, 20 ft and 19 ft, respectively. We recommend that the existing fill within the building area be removed to a depth which will provide a suitable naturally - occurring non -organic excavation base for the support of structural t fill. The excavation should be oversized beyond the outline of the proposed building enough to allow for the proper placement of structural fill. At the location of Boring 5, possible fill was encountered at a depth of 20.5 ft which extended to 27 ft below the existing ground surface. It is possible that this fill would be 'suatable for the support of overlying structural fill and founda- tions. unda- tions. We recommend that this soil as well as the entire excava- tion base be observed and tested by an experienced STS Technician in order to determine its suitability for support of additional i fill.