Expanded Longitudinal Deformation Profile in Tunnel Excavations Considering Rock Mass Conditions via 3D Numerical Analyses
- Title
- Expanded Longitudinal Deformation Profile in Tunnel Excavations Considering Rock Mass Conditions via 3D Numerical Analyses
- Author
- 유한규
- Keywords
- tunnel; longitudinal deformation profile; numerical analysis; FLAC; convergence
- Issue Date
- 2021-06
- Publisher
- MDPI
- Citation
- APPLIED SCIENCES-BASEL, v. 11, NO 12, Page. 5405-5405
- Abstract
- In the convergence–confinement method, the longitudinal deformation profile (LDP) serves
as a graphical representation of the actual tunnel convergence (both ahead of and behind the face);
therefore, it is considered important for determining the distance of support installation from the
face or the timing after excavation in this method. The LDP is a function of the rock mass quality,
excavation size, and state of in situ stresses; thus, obtaining the LDP according to the rock mass
conditions is essential for analyzing the complete behavior of convergence during tunnel excavation.
The famous LDP shows that the best fit for the measured values of tunnel internal displacement
reported simply expresses the ratio of the preceding displacement as approximately 0.3. This can
lead to an error when predicting the ratio of the preceding displacement while neglecting the rock
conditions; consequently, a complete tunnel behavior analysis cannot be realized. To avoid such
error, the finite difference method software FLAC 3D is used to develop an expanded longitudinal
deformation profile (ELDP) according to the rock mass conditions. The ELDP is represented by
graphs featuring different shapes according to the rock mass rating (RMR), and the empirical formula
of the LDP best fitted for the tunnel convergence measurement values is expanded. This expanded
LDP formula is proposed in a generalized form, including the parameters α and β from the empirical
equation. These parameters α and β are expressed as functions of the RMR and initial stress. Statistical
analysis results of the 3D numerical analysis of 35 cases were analyzed in the ranges of α = 0.898–2.416
and β = 1.361–2.851; this result is based on the empirical formula of Hoek (1999) (α = 1.1, β = 1.7),
which was expanded in the current study according to the rock quality and initial stress conditions.
- URI
- https://www.mdpi.com/2076-3417/11/12/5405https://repository.hanyang.ac.kr/handle/20.500.11754/171626
- ISSN
- 20763417
- DOI
- 10.3390/app11125405
- Appears in Collections:
- COLLEGE OF ENGINEERING SCIENCES[E](공학대학) > CIVIL AND ENVIRONMENTAL ENGINEERING(건설환경공학과) > Articles
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