No abstract

No abstract

In-situ capping is a method to manage contaminated sediments and minimize dredging for environmental remediation projects. Placement of a cap on soft sediments poses challenges to the geotechnical stability of the cap and underlying sediments. Failures of in-situ caps sliding over subaqueous soft sediments are not uncommon. The current state of practice for the geotechnical design and construction of in-situ caps on soft sediments is based largely on experience. Various construction techniques, such as placing thin lifts of cap materials in stages and allowing sufficient time between each lift, are used in an attempt to prevent cap failures. However, there is a lack of guidance for the evaluation of geotechnical properties of soft sediments and the assessment of stability of the cap and underlying sediments during placement. This paper presents a method that was developed to evaluate the geotechnical stability of an in-situ cap placed on soft sediments. A technical approach is presented to estimate the design lift thickness of the cap and the waiting period between lifts.

Geotextile tubes provide a quick and potentially cost-effective solution for dewatering. Use of geotextile tubes to dewater contaminated materials causes less impact on the environment, because the slurry-like contaminated materials are contained in the tubes during the process. In some cases, geotextile tubes need to be stacked in multiple layers because of limited site footprint. A parametric study was carried out to evaluate the slope stability of stacked geotextile tubes. Results of the study are presented in this paper as slope stability charts. These charts can be used to quickly evaluate the feasibility of a project that involves stacked geotextile tubes with regard to geotechnical slope stability.

No abstract