Stress reduction factor characterization for highly stressed jointed rock based on tunneling data from Pakistan
- Title
- Stress reduction factor characterization for highly stressed jointed rock based on tunneling data from Pakistan
- Author
- 유한규
- Issue Date
- 2017-08
- Publisher
- ASEM17
- Citation
- The 2017 International Conference on Tunnels and Underground Spaces (ICTUS17), Page. 1-18
- Abstract
- Stress Reduction Factor (SRF) which is the most difficult parameter to characterize in
Q (Tunneling Quality Index) system is targeted in this study for highly stressed jointed rock
in tunneling. As there are no criteria for this purpose in empirical tunnel design, an attempt
has been made in this regard using 542 NATM tunnel sections mapping of four tunneling
projects from Pakistan. These already supported sections are used for the back calculation
of SRF. SRF values measured from the already available equations did not match with the
calculated values from back analysis based on mining cases and without considering the
magnitude of rock fracturing. Empirical equations proposed here are based on the data of
these tunnel sections and match well with the calculated values. Two types of calculated
SRF (SRFQ and SRFQC) from back analysis are dependent on the intact rock strength. In
proposed equations, SRFQ (SRF calculated from original Q-system equation) is dependent
on the relative block size and the ratio of intact rock strength to major principal stress. The
effect of intact rock strength on SRF is also determined from the available data by plotting
SRFQC (SRF calculated from normalized Q-system equation) against relative block size for
different ranges of UCS and ratio of intact rock strength to major principal stress. The
proposed equations are applied to calculate rock quality (Q or Qc) for highly stressed
cases of the jointed rock mass of head race and diversion tunnels of another four
hydropower tunnels from Pakistan with various cross sections. The empirical support
design of these tunnels based on Q or Qc are numerically analyzed and verified in term of
total displacement and plastic zones before and after support installation and the
performance of liner was also validated based on capacity diagrams.
- URI
- http://www.i-asem.org/asem17_publication.html#ICTUS17https://repository.hanyang.ac.kr/handle/20.500.11754/72262
- ISBN
- 978-89-89693-39-0
- Appears in Collections:
- COLLEGE OF ENGINEERING SCIENCES[E](공학대학) > CIVIL AND ENVIRONMENTAL ENGINEERING(건설환경공학과) > Articles
- Files in This Item:
- 2017.08_유한규_Stress reduction factor characterization for highly stressed jointed rock based on tunneling data from Pakistan.pdfDownload
- Export
- RIS (EndNote)
- XLS (Excel)
- XML