This award supports the collection of basic soil indices and compaction data for approximately 100 samples of freshly excavated dredged material (DM) under the auspices of US Corps of Engineers (USACE) contract number W912BU-06-C-0024, entitled, Renewable Capacity at the Fort Mifflin Disposal Area." This 1-year (2006/7) and first of its kind beneficial use contract features the removal of 500,000 cubic yards (CY) of unmodified DM from a 100-acre containment and disposal facility (CDF) in Philadelphia for mine reclamation. The award leverages a unique and time critical opportunity to collect targeted samples of soft, fine-grained DM (OH, MH, CH, OL, ML, and CL soils) for materials testing.
The main materials management strategy historically utilized for DM has been the hydraulic placement of DM in CDFs, and other forms of upland disposal have focused on pozzolanic-based treatment (for contaminated DM). As such, raw DM compaction data is scarce, which introduces challenges for use in fill construction mainly due to unfamiliarity and high material variability. Preliminary work in this area has indicated that DM does not adhere to the traditionally used Ohio DOT family of compaction curves, which allows for the rapid adjustment of compaction criteria in the field owing to changes in the fill media.
Accordingly, this SGER award resolves an important data gap (compaction data) which can enable the use of DM in constructed fills in and near the urban, coastal environment where the material is generated. The collection of soil index and compaction data (~100 suites) is essential for determining if a family of one-point Proctor curves (e.g., AASHTO T272) can be developed for DM, and the extent to which this set of curves is analogous to the ODOT family of curves. Relationships and correlations between basic soil indices and compaction behavior also will be explored, including the unclear role of organic matter content on soil properties.
The quantitative data provided by this work will have immediate, tangible and real impacts on an industry struggling to overcome barriers to implementing beneficial use by enlarging essential data sets that support industry acceptance of sustainable geotechnics approaches to urban fill construction and land reclamation.
