Characterizing Monotonic Behavior of Pond Ash within Critical State Approach: Fid-Bau Portal

Characterizing Monotonic Behavior of Pond Ash within Critical State Approach

Zhang, Jiajun / Lo, Sik-Cheung Robert / Rahman, Md Mizanur / Yan, Jun

The monotonic behavior of pond ash was studied experimentally and with a particular focus on evaluating the applicability of critical state soil mechanics framework in synthesizing and modeling the observed mechanical behavior. Specimens were reconstituted with a paste deposition technique that closely mimics the wet disposal of dominantly fine coal ash in ash ponds. This technique can produce segregation-free specimens over a wide range of as-formed density states. The test results indicated that the observed behavior was similar to granular geomaterials, except that only nonflow behavior could be observed in undrained shearing. More importantly, a unique and consistent critical state line (CSL) in triaxial compression was obtained in both $q - p^{'}$ and $e - \log (p^{'})$ planes irrespective of its drainage conditions, initial density states, and stress histories. The CSL in the $e - \log (p^{'})$ plane was used to predict behavior patterns. It was found that the state parameter, as defined relative to the CSL in $e - \log (p^{'})$ plane, correlates with important modeling parameters. Thus, this study unambiguously supports the applicability of critical state soil mechanics framework in synthesizing and modeling the behavior of pond ash.