Evaluation of turbulent flow conditions in rock cracks and feasibility of a new grouting method for laminar and turbulent conditions

H. Kishi, T. Kakue, Hideo Komine, S. Murakami

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    Abstract

    Precise evaluation of the permeability in a dam foundation is extremely important for reasonable dam foundation treatment. The Lugeon test of permeability assumes a laminar flow around a test section in a test hole. However, it is often pointed that the flow around the section is usually a turbulent flow. In such cases, the permeability is underestimated. To investigate this matter further, laboratory tests of permeability were conducted on single cracks of boring cores. In this experiment, water was used to evaluate the transfer condition from a laminar flow to a turbulent flow. Results show that the critical Reynolds numbers were on the order of several hundreds, which is much lower than the standard number of 2,000 for the flow between a pair of parallel plates. Subsequently, the progressive conditions of the turbulent flow in the Lugeon tests were evaluated using a new theoretical equation representing the relation between the injection pressure and flow rate under laminar and turbulent conditions on a radial flow model between parallel plates. The outcome indicated that the turbulent flow was highly developed in the tests. Based on the results presented above, the flow condition in a rock mass during grouting was evaluated. The evaluation model was the previous model expanded for use with non-Newtonian fluids. Using this model, a new injection method was proposed for grout particles to penetrate to the target area, and then subsequently settle and block up cracks from the far side toward the near side around a borehole. Using this method, the grout-flow condition is kept turbulent with high carrying power in the interval of penetration to the target area. Then the condition becomes laminar for settlement. The feasibility of this method was evaluated using results of calculations done with the model.

    Original languageEnglish
    Title of host publicationISRM International Symposium - 8th Asian Rock Mechanics Symposium, ARMS 2014
    PublisherInternational Society for Rock Mechanics
    Pages2661-2670
    Number of pages10
    ISBN (Print)9784907430030
    Publication statusPublished - 2014
    Event8th Asian Rock Mechanics Symposium, ARMS 2014 - Sapporo, Japan
    Duration: 2014 Oct 142014 Oct 16

    Other

    Other8th Asian Rock Mechanics Symposium, ARMS 2014
    CountryJapan
    CitySapporo
    Period14/10/1414/10/16

    Keywords

    • Grouting
    • Laminar and turbulent flow
    • Permeability
    • Reynolds number

    ASJC Scopus subject areas

    • Geophysics
    • Geochemistry and Petrology

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  • Cite this

    Kishi, H., Kakue, T., Komine, H., & Murakami, S. (2014). Evaluation of turbulent flow conditions in rock cracks and feasibility of a new grouting method for laminar and turbulent conditions. In ISRM International Symposium - 8th Asian Rock Mechanics Symposium, ARMS 2014 (pp. 2661-2670). International Society for Rock Mechanics.