In situ capping of contaminated sediments in rivers, lakes and ponds has been successfully used to contain the contaminants in sediments and prevent water contamination.
While capping is a good alternative for remediation, the cap load may cause consolidation-induced migration of Non-Aqueous Phase Liquids (NAPLs). In this study, the consolidation properties of NAPL-contaminated sediments were investigated. Anisotropic consolidation tests were conducted on very soft contaminated sediment specimens in a modified triaxial cell. Kaolinite was used to represent the sediment solid phase and Soltrol 130 (a type of mineral oil) was used to represent the NAPL. Compression index (Cc) and coefficient of consolidation (Cv) values were obtained for specimens at various NAPL saturations.
The hydraulic conductivity values were back-calculated by using the Cv values. The results indicate that NAPL can be expelled during consolidation if its saturation is high enough. While there is not a significant change in the Cc values for different NAPL contents, Cv values increase significantly when the NAPL saturation increases. When designing a cap system for contaminated sediments, the effect of NAPL on consolidation behavior is an important consideration.
- Geosyntec Authors: Mustafa B Erten
- Title: Consolidation Properties of NAPL Contaminated Sediments
- Event or Publication: Proceedings of GeoCongress 2012: State of the Art and Practice in Geotechnical Engineering
- Practice Areas: Geotechnical and Geoenvironmental Engineering
- Date: 2012
- Location: Oakland, California
- Type: Presentation