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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 25, Issue 6 - Dec 2015
Volume 25, Issue 5 - Oct 2015
Volume 25, Issue 4 - Aug 2015
Volume 25, Issue 3 - Jun 2015
Volume 25, Issue 2 - Apr 2015
Volume 25, Issue 1 - Feb 2015
Selecting the target year
A Study of Shield TBM Tunnelling-induced Volume Loss Estimation Considering Shield Machine Configurations and Driving Data
Park, Hyunku ; Chang, Seokbue ; Lee, Seungbok ;
Tunnel and Underground Space, volume 25, issue 5, 2015, Pages 397~407
DOI : 10.7474/TUS.2015.25.5.397
Estimation of shield TBM tunnelling-induced volume loss is of great importance for ground settlement control. This study proposed a simple method for evaluation of volume loss during TBM tunnlling, which is able to take into account of shield machine configurations and main driving data in calculation. The method was applied to analyze the tunnelling cases with earth pressure balanced and slurry pressure balanced shiled TBM, and mostly, reasonable agreements with monitoring results were found. Additional discussions were made for some disagreements.
Research and Development Trends for Mine Subsidence Prevention Technology in Korea
Kim, Soo Lo ; Park, Joo Hyun ;
Tunnel and Underground Space, volume 25, issue 5, 2015, Pages 408~416
DOI : 10.7474/TUS.2015.25.5.408
The collapse of the underground cavities and voids, which were made for developing mineral resources, can cause the subsidence of the ground surface in the residential areas. During the Japanese colonial era and the 1960's mining boom period, lots of mines had been developed indiscriminately in Korea. Due to complicated geological conditions and mining methods, many of dangerous underground mine cavities with steep slopes had been generated at the shallow surface. Due to such conditions, it is difficult to directly apply valid foreign reclamation practice for the cavities in Korea environments. It is necessary to develop the efficient ground stabilization technologies for the Korea underground mine conditions to solve abandoned mine reclamation properly. Therefore, MIRECO and Korea government have been carrying out practical researches and technical developments together with other academic researchers and reclamation business partners, and various practical solutions such as surveying and exploration methods, proper cavity filling materials and reinforcement methods have been developed with application in the mine field. In this article, up to date technologies and R&D trends in the field of mine subsidence prevention technology are broadly reviewed to establish the future direction of a research and development.
A Design and Operation of EPBM Applied in Fort Canning Boulder Bed of Singapore
Kim, Uk Young ; Noh, Seung Hwan ; Noh, Sang Rim ;
Tunnel and Underground Space, volume 25, issue 5, 2015, Pages 417~422
DOI : 10.7474/TUS.2015.25.5.417
This paper introduces the design and operational considerations for TBM tunneling in boulder bed which poses significant problems in terms of advance rate and machine wear. Managing these problems is difficult since normal soil investigation techniques do not accurately predict the presence and frequency of boulders. This has leads to considerable extra costs and delays during construction. In this paper, EPBM design and operational parameters, cutter wear characteristics and soil conditioning method in soft ground condition were studied and key successes were highlighted for future projects in similar ground condition.
Influence of Pillar Width on the Stability of Twin Tunnels Using Scaled Model Tests
Kim, Jong-Woo ;
Tunnel and Underground Space, volume 25, issue 5, 2015, Pages 423~434
DOI : 10.7474/TUS.2015.25.5.423
Scaled model tests were performed to investigate the influence of pillar width, rock strength and isotropy/anisotropy on the stability of twin tunnels. Test models had respectively different pillar widths, uniaxial compressive strengths of modelling materials and model types, where both the deformation behaviors around tunnels and the biaxial pressure data at a time of pillar cracking were analysed. The cracking pressures of the higher strength models were higher than the lower strength models, whereas the percentage of cracking pressure to uniaxial compressive strength of modelling materials showed an opposite tendency. The cracking pressures of the shallower pillar width models were lower than the thicker models, moreover the percentage of that showed a same tendency. It has been found that the pillar width was one of the main factors influencing on the stability of twin tunnels. Model types such as isotropy/anisotropy also influenced on the stability of twin tunnels. The anisotropic models showed lower values of both cracking pressures and the percentage of that than the isotropic models, where the pillar cracks of anisotropic models were generated with regard to the pre-existing joint planes.
Variation of Physical and Microstructural Properties of Limestone caused by Artificial Freezing and Thawing
Park, Jihwan ; Park, Hyeong-Dong ;
Tunnel and Underground Space, volume 25, issue 5, 2015, Pages 435~449
DOI : 10.7474/TUS.2015.25.5.435
Physical and microstructural properties of Pungchon and Maggol limestone were investigated quantitatively during 50 cycles of artificial freezing and thawing test. There were decrease in dry weight and P,S-wave velocity, and increase in absorption rate in both rock types. Porosity, pore volume, equivalent diameter, throat thickness and pore orientation were analyzed using X-ray computed tomography images. Porosity increased, and initiation and expansion of pores were investigated as weathering progresses. Physical and microstructural variation in Maggol limestone was larger than that of Pungchon limestone because Maggol limestone has more pores and microcracks at initial state. As this study analyzes physical and microstructural properties of rock specimens comprehensively, it can be applied to further rock weathering study and can be used as fundamental data of construction and resource development in cold regions.
Characteristics of Block Hydraulic Conductivity of 2-D DFN System According to Block Size and Fracture Geometry
Han, Jisu ; Um, Jeong-Gi ;
Tunnel and Underground Space, volume 25, issue 5, 2015, Pages 450~461
DOI : 10.7474/TUS.2015.25.5.450
Extensive numerical experiments have been carried out to investigate effect of block size and fracture geometry on hydraulic characteristics of fractured rock masses based on connected pipe flow in DFN systems. Using two fracture sets, a total of 72 2-D fracture configurations were generated with different combinations of fracture size distribution and deterministic fracture density. The directional block conductivity including the theoretical block conductivity, principal conductivity tensor and average block conductivity for each generated fracture network system were calculated using the 2-D equivalent pipe network method. There exist significant effects of block size, orientation, density and size of fractures in a fractured rock mass on its hydraulic behavior. We have been further verified that it is more difficult to reach the REV size for the fluid flow network with decreasing intersection angle of two fracture sets, fracture plane density and fracture size distribution.
Topographic Survey at Small-scale Open-pit Mines using a Popular Rotary-wing Unmanned Aerial Vehicle (Drone)
Lee, Sungjae ; Choi, Yosoon ;
Tunnel and Underground Space, volume 25, issue 5, 2015, Pages 462~469
DOI : 10.7474/TUS.2015.25.5.462
This study carried out a topographic survey at a small-scale open-pit limestone mine in Korea (the Daesung MDI Seoggyo office) using a popular rotary-wing unmanned aerial vehicle (UAV, Drone, DJI Phantom2 Vision+). 89 sheets of aerial photos could be obtained as a result of performing an automatic flight for 30 minutes under conditions of 100m altitude and 3m/s speed. A total of 34 million cloud points with X, Y, Z-coordinates was extracted from the aerial photos after data processing for correction and matching, then an orthomosaic image and digital surface model with 5m grid spacing could be generated. A comparison of the X, Y, Z-coordinates of 5 ground control points measured by differential global positioning system and those determined by UAV photogrammetry revealed that the root mean squared errors of X, Y, Z-coordinates were around 10cm. Therefore, it is expected that the popular rotary-wing UAV photogrammetry can be effectively utilized in small-scale open-pit mines as a technology that is able to replace or supplement existing topographic surveying equipments.
A Numerical Study on the Reinforcement Method of a Pillar Using Tension Bolts at the Connecting Part between 2-Arch Tunnels and Parallel Tunnels
Park, Yeon-Jun ; Choi, Jae-Jin ;
Tunnel and Underground Space, volume 25, issue 5, 2015, Pages 470~486
DOI : 10.7474/TUS.2015.25.5.470
Two-arch tunnels require minimal spacing between the 2 tunnels and thus occupy small amount of land compared to parallel tunnels. But it is rather expensive. The parallel tunnel is not as expensive, but it requires more land than 2-arch tunnels. This may cause a problem when there is a land shortage. The new design is to connect these two types of tunnels by another pair of parallel tunnels where the separation distance is gradually increasing. The applicability of this new design to the cases where rock condition is not even fair has to be verified since the width of the pillar between the connecting tunnels can be quite narrow. Therefore both two and three dimensional numerical analyses were conducted and pillar stability was examined for rock classes IV and V in two different ways. Results showed that this new design is still effective for poor rock conditions if central pillar is properly reinforced by tension bolts as long as overburden is less than five times of the tunnel diameter.