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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Tunnel and Underground Space
Journal Basic Information
Journal DOI :
Korean Society for Rock Mechanics
Editor in Chief :
Volume & Issues
Volume 21, Issue 6 - Dec 2011
Volume 21, Issue 5 - Oct 2011
Volume 21, Issue 4 - Aug 2011
Volume 21, Issue 3 - Jun 2011
Volume 21, Issue 2 - Apr 2011
Volume 21, Issue 1 - Feb 2011
Selecting the target year
A Study of RMR in Tunnel with Risk Factor of Collapse
Jang, Hyong-Doo ; Yang, Hyung-Sik ;
Tunnel and Underground Space, volume 21, issue 5, 2011, Pages 333~340
RMR is most strongly adopted rock classification method to scheme support system in domestic tunnel. However the RMR, which is based on geological survey during design stage of tunnel, can't present the real ground accurately. In this study, authors suggested Weighted-RMR (W-RMR) which is considered weighted value of risk factors of collapse due to prevent collapse and roof falls during tunneling. According to the application of W-RMR to Bye-Gye tunnel, we could change support type flexibly by the risk factors on a face of tunnel.
A Case Study on the Design of Tunnel Excavation in Geological Anomalies
Yoo, Joung-Hoon ; Kim, Yang-Kyun ; Chung, Chul-Hwa ;
Tunnel and Underground Space, volume 21, issue 5, 2011, Pages 341~348
As a result of the detailed site investigation performed for the design of a 4.3 km long tunnel, geological anomalies of four fault zones and a rock boundary were discovered on the tunnel route. Most of all, it was confirmed that pyrite, which may corrode steel material, is contained inside the geological anomalies, and pressured ground water flows out of the fault fractured zone. To overcome these geological conditions, antisulfur concrete for the concrete lining and anticorrosive swelling rock bolts are designed in the pyrite-containing sections. For the sections where a great amount of groundwater outflows, water blocking methods including grouting are applied according to the result of numerical analyses on the seepage. In addition, since the past earthquakes occurred around Korea have take place mainly near fault zones, seismic analyses were performed based on the Soil-Structure Interaction (SSI) concept and the strength of concrete tunnel lining is designed to be 27 MPa from 24 MPa in order to reinforce the tunnel structure.
A Study on the P Wave Arrival Time Determination Algorithm of Acoustic Emission (AE) Suitable for P Waves with Low Signal-to-Noise Ratios
Lee, K.S. ; Kim, J.S. ; Lee, C.S. ; Yoon, C.H. ; Choi, J.W. ;
Tunnel and Underground Space, volume 21, issue 5, 2011, Pages 349~358
This paper introduces a new P wave arrival time determination algorithm of acoustic emission (AE) suitable to identify P waves with low signal-to-noise ratio generated in rock masses around the high-level radioactive waste disposal repositories. The algorithms adopted for this paper were amplitude threshold picker, Akaike Information Criterion (AIC), two step AIC, and Hinkley criterion. The elastic waves were generated by Pencil Lead Break test on a granite sample, then mixed with white noise to make it difficult to distinguish P wave artificially. The results obtained from amplitude threshold picker, AIC, and Hinkley criterion produced relatively large error due to the low signal-to-noise ratio. On the other hand, two step AIC algorithm provided the correct results regardless of white noise so that the accuracy of source localization was more improved and could be satisfied with the error range.
An Estimation of the Excavation Damaged Zone at the KAERI Underground Research Tunnel
Lee, Chang-Soo ; Kwon, Sang-Ki ; Choi, Jong-Won ; Jeon, Seok-Won ;
Tunnel and Underground Space, volume 21, issue 5, 2011, Pages 359~369
In this study, physical, mechanical, and thermal properties of rock samples were investigated to estimate the Excavation Damaged Zone (EDZ) developed during the construction of the KAERI Underground Research Tunnel. The average porosity in the EDZ was increased by about 140%. The average wave velocity, Young's modulus, and uniaxial compressive strength in the EDZ were decreased by about 11, 37, and 16%, respectively. And the thermal conductivity in the EDZ was decreased by about 20%. From the laboratory tests, the EDZ size could be estimated to be around 1.1-2.4 m.
Evaluation of Groundwater Flow through Rock Mass around Development Openings of Mine
Yoon, Yong-Kyun ;
Tunnel and Underground Space, volume 21, issue 5, 2011, Pages 370~376
To design the drainage system of a mine, it is very important to evaluate the groundwater inflow to the mine workings. In this study, continuous steady state flow through rock mass around mine openings developed in Sungok area of Gagok Mine was analyzed. Saturated only model and Saturated/unsaturated model were used as material models of rock mass. Groundwater quantities flowing into Sungok 160 level which is 1216 m long are computed as 1450
/day in case of a saturated model and as 1071
/day in case of a saturated/unsaturated model. An effect that hydraulic conductivity has on inflow turned out be greater than precipitation and inflow increased linearly with increase of hydraulic conductivity. It was found that change of hydraulic conductivity ratio and orientation have an impact on the variation of inflow and water table.
Resisting Behavior of Fully-Grouted Rock Bolts with Compressible Spacers
Hwang, Yong-Sub ; Lee, Sang-Duk ;
Tunnel and Underground Space, volume 21, issue 5, 2011, Pages 377~385
In order to prove the applicability of rock bolts with compressible spacers, laboratory model tests and large scale model tests were conducted. Laboratory model tests were performed in various distance of compressible spacers to determine the optimal distance of compressible spacers. The optimal distance of compressible spacers was found that is 1/4 of rock bolts unit length. Large scale model tests that the size was 0.6 m (diameter)
4.45 m (length) were conducted. Test results showed that pull out resistance could be increased up to 15% larger than that of unused case by using compressible spacers.
A Study for the Estimation of Joint Diameter Distribution Using the Trace Length Distribution from Cylindrical Window Survey
Jeon, Ki-Hwan ; Song, Jae-Joon ; Jo, Young-Do ;
Tunnel and Underground Space, volume 21, issue 5, 2011, Pages 386~393
This study suggests an algorithm for estimating joint diameter distribution in rock mass from the joint trace length distribution around a circular tunnel. For estimating the joint diameter distribution, the concept of Joint Center Volume (JCV) suggested by Song. (2005) was applied and the calculation method of JCV for the cylindrical window survey was developed by using the complete survey method. The estimated joint diameter distribution was verified against the original joint diameter distribution by Monte-Carlo simulation. It was observed that the estimated joint diameter distribution was converged to the original joint diameter distribution with less than 20% of error.
Geomechanical Stability of Underground Lined Rock Caverns (LRC) for Compressed Air Energy Storage (CAES) using Coupled Thermal-Hydraulic-Mechanical Analysis
Kim, Hyung-Mok ; Rutqvist, Jonny ; Ryu, Dong-Woo ; Synn, Joong-Ho ; Song, Won-Kyong ;
Tunnel and Underground Space, volume 21, issue 5, 2011, Pages 394~405
In this paper, we applied coupled non-isothermal, multiphase fluid flow and geomechanical numerical modeling using TOUGH-FLAC coupled analysis to study the complex thermodynamic and geomechanical performance of underground lined rock caverns (LRC) for compressed air energy storage (CAES). Mechanical stress in concrete linings as well as pressure and temperature within a storage cavern were examined during initial and long-term operation of the storage cavern for CAES. Our geomechanical analysis showed that effective stresses could decrease due to air penetration pressure, and tangential tensile stress could develop in the linings as a result of the air pressure exerted on the inner surface of the lining, which would result in tensile fracturing. According to the simulation in which the tensile tangential stresses resulted in radial cracks, increment of linings' permeability and air leakage though the linings, tensile fracturing occurred at the top and at the side wall of the cavern, and the permeability could increase to
from initially prescribed
. However, this air leakage was minor (about 0.02% of the daily air injection rate) and did not significantly impact the overall storage pressure that was kept constant thanks to sufficiently air tight surrounding rocks, which supports the validity of the concrete-lined underground caverns for CAES.