Evaluation of pulsed-phase-lock-loop technology applied to mine roof bolt load measurement
Advanced Search
Select up to three search categories and corresponding keywords using the fields to the right. Refer to the Help section for more detailed instructions.

Search our Collections & Repository

All these words:

For very narrow results

This exact word or phrase:

When looking for a specific result

Any of these words:

Best used for discovery & interchangable words

None of these words:

Recommended to be used in conjunction with other fields

Language:

Dates

Publication Date Range:

to

Document Data

Title:

Document Type:

Library

Collection:

Series:

People

Author:

Help
Clear All

Query Builder

Query box

Help
Clear All

For additional assistance using the Custom Query please check out our Help Page

i

Evaluation of pulsed-phase-lock-loop technology applied to mine roof bolt load measurement

Filetype[PDF-2.43 MB]


  • English
    • Details You May Also Like

    Details:

    • Personal Author:
      Steblay, Bernard J.
    • Corporate Authors:
      United States. Bureau of Mines.
    • Description:
      "The Bureau of Mines has attempted to use ultrasonic signal travel- time measurements to measure loaded roof bolt strains. The strain measurements are then related to roof bolt loads through equations or empirical calibrations. Such techniques offer the potential of accurate, rapid bolt load measurement that does not disturb the anchorage. This report presents the research findings for a specific type of ultrasonic measurement instrument using a pulsed- phase-lock-loop technique. This technique measures signal travel time indirectly by measuring frequency changes. A complete development of the applicable theory and detailed derivations of key equations is presented along with empirical laboratory and field results. The differences between anticipated and measured behaviors are analyzed and discussed. The report identifies problems encountered in applying pulsed-phase-lock-loop technology to roof bolt load measurement and provides potential solutions to many of them. A key assumption of pulsed-phase-lock-loop theory is that driving and reflected signal frequencies will always be equal. Findings showed that not only were actual frequencies not equal but they were not stable or simply related. Reflection wave shape also was not stable. The ramification of these findings and ways to minimize their adverse effects are presented." - NIOSHTIC-2

      NIOSHTIC no. 10007391

    • Subjects:
    • Series:
      Report of investigations (United States. Bureau of Mines) ; 9293
    • Document Type:
      Report
    • Collection(s):
    • Main Document Checksum:
    • Download URL:
    • File Type:

    Supporting Files

    • No Additional Files

    More +

    You May Also Like

    Checkout today's featured content at stacks.cdc.gov