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Multiphysics Simulation and Innovative Characterization of Freezing Soils

Liu, Zhen
http://rave.ohiolink.edu/etdc/view?acc_num=case1350331910

Abstract Details

2013, Doctor of Philosophy, Case Western Reserve University, Civil Engineering.
Freezing soils are significant due to their wide occurrence in nature. A thorough understanding of their behaviors is challenged by their susceptibilities to multiphysical processes as the result of their porous nature. Further advancements in research related to freezing soils call for holistic simulation techniques and innovative instruments. This study reviewed previous research to lay down a knowledge base for investigating the behaviors of porous materials under frost action. Based on the review, it was concluded that more comprehensive multiphysics frameworks and innovative characterization techniques are highly desirable for further advancing this topic. For the purpose, a comprehensive multiphysics framework was developed by integrating and taking advantage of the knowledge base. The new model couples heat equation for heat transfer, modified Richards’ equation for fluid transfer, and mechanical constitutive relationships. Auxiliary relationships, such as the similarity between drying and freezing processes and the Clapeyron equation for phase equilibrium during phase transition, were utilized to describe the frost action. The coupled nonlinear equation system was solved under typical boundary conditions using the finite element method. To further test the performance and applicability of the model, the simulation code was implemented and verified on instrumented pavement sections and in typical buried pipe scenarios. For pavements, both flexible and rigid pavements were simulated. The simulation results were compared with instrumented data on these test pavements. For pipes, cases involving static and dynamic loads were studied, respectively. Phenomena typical of pipe-soil interactions under frost action were reproduced and several detrimental factors on the safety and durability of buried pipes under frost action were identified. On the experimental side, a new instrumentation technique, i.e., thermo-Time Domain Reflectometry (TDR) sensor, was developed to characterize the behaviors of freezing soils. The thermo-TDR combines temperature sensors and a conventional TDR module. The TDR module and algorithm measured the bulk free water content of soils during the freezing/thawing process, while the built-in thermocouples measured the variation of the internal temperature. The Soil Water Characteristic Curve (SWCC) was obtained from the simultaneously measured TDR and temperature data. The new characterization technique was verified by the filter paper method (ASTM D5298).
Xiong Yu (Committee Chair)
Xiangwu Zeng (Committee Member)
Brian Metrovich (Committee Member)
Weihong Guo (Committee Member)
Scott Painter (Committee Member)
181 p.
Civil Engineering
Freezing Soil; Multiphysics; Simulation; Porous Materials; Pavement; Buried Pipes; Frost Action; Thermo-TDR; Soil Water Characteristic Curve

Recommended Citations

Citations

  • Liu, Z. (2013). Multiphysics Simulation and Innovative Characterization of Freezing Soils [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1350331910

    APA Style (7th edition)

  • Liu, Zhen. Multiphysics Simulation and Innovative Characterization of Freezing Soils. 2013. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1350331910.

    MLA Style (8th edition)

  • Liu, Zhen. "Multiphysics Simulation and Innovative Characterization of Freezing Soils." Doctoral dissertation, Case Western Reserve University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=case1350331910

    Chicago Manual of Style (17th edition)

case1350331910
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© 2012, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.