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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Tunnel and Underground Space
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Journal DOI :
Korean Society for Rock Mechanics
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Volume & Issues
Volume 26, Issue 4 - Aug 2016
Volume 26, Issue 3 - Jun 2016
Volume 26, Issue 2 - Apr 2016
Volume 26, Issue 1 - Feb 2016
Selecting the target year
Numerical Analysis for Fault Reactivation during Gas Hydrate Production
Kim, Hyung-Mok ; Kim, A-Ram ;
Tunnel and Underground Space, volume 26, issue 2, 2016, Pages 59~67
DOI : 10.7474/TUS.2016.26.2.059
In this paper, we perform a numerical analysis to evaluate the potential of fault reactivation during gas production from hydrate bearing sediments and the moment magnitude of induced seismicity. For the numerical analysis, sequential coupling of TOUGH+Hydrate and FLAC3D was used and the change in effective stress and consequent geomechanical deformation including fault reactivation was simulated by assuming that Mohr-Coulomb shear resistance criterion is valid. From the test production simulation of 30 days, we showed that pore pressure reduction as well as effective stress change hardly induces the fault reactivation in the vicinity of a production well. We also investigated the influence of stress state conditions to a fault reactivation, and showed that normal fault stress regime, where vertical stress is relatively greater than horizontal, may have the largest potential for the reactivation. We tested one simulation that earthquake can be induced during gas production and calculated the moment magnitude of the seismicity. Our calculation presented that all the magnitudes from the calculation were negative values, which indicates that induced earthquakes can be grouped into micro-seismic and as small as hardly perceived by human beings. However, it should be noted that the current simulation was carried out using the highly simplified geometric model and assumptions such that the further simulations for a scheduled test production and commercial scale production considering complex geometric conditions may produce different results.
A Study on Shear Characteristics of a Rock Discontinuity under Various Thermal, Hydraulic and Mechanical Conditions
Kim, Taehyun ; Jeon, Seokwon ;
Tunnel and Underground Space, volume 26, issue 2, 2016, Pages 68~86
DOI : 10.7474/TUS.2016.26.2.068
Understanding the frictional properties of rock discontinuities is crucial to ensure the stability of underground structures. In particular, the frictional behavior at depth depends on the complex interaction among mechanical, hydraulic, thermal and chemical characteristics and their coupled effects. In this study, a series of shear tests were carried out in a triaxial compression chamber to investigate the shearing behavior of saw-cut granite surface and rough shear surface of synthetic rocks. The test results were analyzed using Coulomb`s shear strength criterion. The frictional behavior of saw-cut granite surface showed little variation at different confining, water pressures and temperature conditions, however in case of synthetic rocks, the frictional behavior showed different trend depending on normal stress level. In addition, the variation of stiffness and dilation at different testing conditions were analyzed, and the stiffness and dilation showed little variation at different water pressures and temperature conditions.
Development of a Windows-based Program for Discrete Event Simulation of Truck-Loader Haulage Systems in an Underground Mine
Choi, Yosoon ; Park, Sebeom ; Lee, Sung-Jae ; Baek, Jieun ; Jung, Jihoo ; Park, Han-Su ;
Tunnel and Underground Space, volume 26, issue 2, 2016, Pages 87~99
DOI : 10.7474/TUS.2016.26.2.087
We developed a Windows-based program for discrete event simulation of truck-loader haulage systems in an underground mine. The Daesung MDI limestone mine located in Samcheok City, Gangwon Province, Korea was selected as the study area to design the program. The developed program is composed of the graphic user interface (GUI) and simulation engine implemented by Visual Basic.NET 2012 and the GPSS/H simulation language, respectively. When a user sets up input parameters for the discrete event simulation through GUI, the program activates the simulation engine, and then simulation results are displayed on GUI. This paper describes the details of the program development as well as its applications to the study area to determine the optimal number of trucks dispatched at each loading point under different operating conditions.
Spatial Distribution Functions of Strength Parameters for Simulation of Strength Anisotropy in Transversely Isotropic Rock
Lee, Youn-Kyou ;
Tunnel and Underground Space, volume 26, issue 2, 2016, Pages 100~109
DOI : 10.7474/TUS.2016.26.2.100
This study suggests three spatial distribution functions of strength parameters, which can be adopted in the derivation of failure conditions for transversely isotropic rocks. All three proposed functions, which are the oblate spheroidal function, the exponential function, and the function based on the directional projection of the strength parameter tensor, consist of two model parameters. With assumption that the cohesion and friction angle can be described by the proposed distribution functions, the transversely isotropic Mohr-Coulomb criterion is formulated and used as a failure condition in the simulation of the conventional triaxial tests. The simulation results confirm that the failure criteria incorporating the proposed distribution functions could reproduce the general trend in the variations of the axial stress at failure and the directions of failure planes with varying inclination of the weankness planes and confining pressure. Among three distribution functions, the function based on the directional projection of the strength parameter tensor yields the highest axial strength, while the axial strength estimated by the oblate spheroidal distribution function is the lowest.
Applicability Evaluation of Tailing Admixture as Grout Material
Kim, Daehyeon ; Noh, Jeongdu ; Kang, Seong-Seung ;
Tunnel and Underground Space, volume 26, issue 2, 2016, Pages 110~119
DOI : 10.7474/TUS.2016.26.2.110
The purpose of this study is to evaluate the applicability of tailing in the
mine as a grout material. For the purpose, XRD analysis was performed for mineralogical properties of tailing. In addition, flow, velocity, and uniaxial compressive strength tests were carried out for physical and mechanical properties of a grout material with the mixing ratio of cement and tailing and curing periods. By the result of XRD analysis, tailing of the mine was found to mostly consist of quartz, galena, and pyrite. The flow observed by the flow test showed decreasing tendency with increasing the mixing ratio of tailing. The velocity was also lowered with increasing the mixing ratio of tailing regardless of curing periods. The uniaxial compressive strength as well as Young`s modulus also show a tendency to decrease with increasing the mixing ratio of tailing independently on the curing periods. Considering only the physical and mechanical properties of a grout material with tailing, the results are considered to be sufficiently used as a grout material. However, since metallic minerals such as galena and pyrite in tailing contents and these are causing environmental contamination, countermeasures should be considered for this problem in future.
A Study on Application of Kuz-Ram model to Domestic Open-pit Limestone Mine
Lee, Seung-Joong ; Kim, Byung-Ryeol ; Choi, Sung-Oong ; Jin, Yeon-Ho ; Jung, Min-Su ; Min, Hyung-Dong ;
Tunnel and Underground Space, volume 26, issue 2, 2016, Pages 120~130
DOI : 10.7474/TUS.2016.26.2.120
Considering the applicability of Kuz-Ram model, which has been used extensively for predicting rock fragmentation size distribution by blasting, to domestic open-pit limestone mine, a total of 21 blasting tests have been executed at an open-pit limestone mine in eastern Gangwon of South Korea. A comparative analysis of field measured value and Kuz-Ram predicted value showed that there are a considerable amount of error in the predicted values regardless of application of various correction parameters for rock factor and uniformity factor; up to 56.45% in mean fragmentation size and 37.52% in uniformity index. Also the problem of applying different correction parameters has been derived even though a similar blasting pattern has been adopted for a same blasting bench. The authors therefore suggest that Kuz-Ram model needs to be modified for a proper application to domestic open-pit limestone mine.
A Study on Stability Analysis of Large Underground Limestone Openings considering Excavation Damaged Zone
Kwon, Min-Hyuk ; Choi, Sung-Oong ; Kim, Chang-Oh ;
Tunnel and Underground Space, volume 26, issue 2, 2016, Pages 131~142
DOI : 10.7474/TUS.2016.26.2.131
Investigation for rock joints, inspection for rock core, and laboratory tests for rock specimens, in this study, have been performed for identification of the extent and properties of Excavation Damaged Zone in a underground limestone mine, which plans to enlarge the size of openings to improve the production rate. Properties of EDZ and surrounding rock masses have been used numerically for discontinuum analysis, and it is concluded that the effect of EDZ can be increased with increasing the opening size and a blasting pattern of high precision can be suggested for the counterplan.