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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
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Volume & Issues
Volume 17, Issue 6 - Dec 2007
Volume 17, Issue 5 - Oct 2007
Volume 17, Issue 4 - Aug 2007
Volume 17, Issue 3 - Jun 2007
Volume 17, Issue 2 - Apr 2007
Volume 17, Issue 1 - Feb 2007
Selecting the target year
Discontinuity Analysis Method using Reverse Engineering
Park, Eui-Seob ; Jung, Yong-Bok ; Ryu, Chang-Ha ; SunWoo, Choon ; Choi, Yong-Kun ; Heo, Sung ; Cheon, Dae-Sung ;
Tunnel and Underground Space, volume 17, issue 3, 2007, Pages 165~174
The technique, which reproduces the figures of objects from measured data of the objects using 3-D laser scanner, is called reverse engineering. Recently, research studies into applications of reverse engineering to rock engineering are increasing in number, in the discontinuity surveys for rock slopes out of man's reach, or rapid discontinuity surveys for wide range areas. For analysis of discontinuity using reverse engineering, a program for processing point clouds data from the 3-D laser scanner, for sampling from these point clouds data, and finally analyzing the discontinuity is needed. However, existing programs rarely have sufficient functions to properly analyze the discontinuities. In this study, a program was developed, which can automatically sample discontinuities from the point clouds data which measured in a rock slope using a 3-D laser scanner, and which can also undertake statistical analysis of the discontinuities. This developed program was verified by the application of discontinuity surveys in a rock slope and a tunnel. By undertaking the discontinuity survey using a 3-D laser scanner and the developed program, the feasibility and rapidity of such surveys is expected to improve in areas out of man's reach in geotechnical surveys. Taking into consideration the fact that the international level of related techniques is at a rudimentary stage, the possibility of prior occupation of a broad market is also expected.
A Study on the Analysis of the Slope Stability Considering Clay Filling in Discontinuity
Min, Kyong-Nam ; Ahn, Tae-Bong ; Yang, Seung-Jun ; Baek, Seon-Gi ; Lee, Tae-Sun ;
Tunnel and Underground Space, volume 17, issue 3, 2007, Pages 175~185
When filling material such as clay is included along the discontinuity, it may cause instability on a slope even if the direction of discontinuity works in a positive way. In the study area, slope sliding occurred at the boundary between a clay filling material and weathered soil because the physical properties differ across the boundary; and this is very similar to the situation where foliation in a rock works as a weak zone during a structural behavior, causing an inter-layer slip. In most analysis, if there exists a clay filling material, a single discontinuity is assumed to perform analysis. In those cases, the discontinuity is modeled as a slip surface within clay. Therefore, the characteristics of the boundary are not considered in the analysis, so that ultimately the physical property of clay usually prevails. The result of evaluating the slope stability affected by clay filling material shows the significant difference in the safety level due to the strength parameter depending on the failure type of the discontinuity by a filling material.
The Influence of Rock Joint Roughness and Normal Stress on Shear Behaviour
Lee, Myoung-Ho ; Kim, Jong-Woo ; Chang, Kwang-Taek ;
Tunnel and Underground Space, volume 17, issue 3, 2007, Pages 186~196
In this study, direct shear tests were carried out on the 30 rock joint samples in order to investigate the influence of roughness and normal stress on the shear behaviour. Joint roughness profiles were measured by use of 3D laser profiler, and then the samples were equally classified into three individual groups according to the roughness index of rock joints. Peak shear strength, residual shear strength, shear stiffness, dilation angle of rock joints were investigated in condition of five different constant normal load. Peak shear strength was increased as roughness index was increased, and the influence of roughness on strength was found to be more considerable in case of lower normal stress condition. Residual shear strength and shear stiffness were increased as roughness index and normal stress were increased. Finally dilation angle was decreased as normal stress was increased, but it was increased as roughness index was increased in the same normal stress condition.
A Study on the Statistical Determination of Design Parameters Considering the Original Distribution Characteristics
Kim, Jong-Gwan ; Yang, Hyung-Sik ;
Tunnel and Underground Space, volume 17, issue 3, 2007, Pages 197~202
In this study, design parameters were determined statistically with and without consideration of original distribution characteristics. Obtained parameters were applied to test numerical analysis and the results were compared. Distribution characteristics of statistically treated parameters show the similar characteristics of original distribution. Mean values show more than 19% of errors between the two cases. Regarding the characteristics as normal distribution can cause distorted results, it is proper to consider the original distribution characteristics of the parameters.
Shear Behavior of Rough Granite Joints Under CNS Conditions
Park, Byung-Ki ; Lee, Chang-Soo ; Jeon, Seok-Won ;
Tunnel and Underground Space, volume 17, issue 3, 2007, Pages 203~215
Stability and mechanical deformation behavior of rock masses are highly dependent on the mechanical characteristics of contained discontinuities. Therefore, mechanical characteristics of the discontinuities should be considered in the design of tunnel and underground structures. In this study, direct shear tests for rough granite joints were carried out under constant normal stiffness conditions. Effects of initial normal stress, shear velocity, and surface roughness on the characteristics of shear strength and deformation behaviors were examined. Results of shear testing under constant normal stiffness conditions reveal that shear behaviors could be classified into two categories, based on the amount of decrease in shear stress at the Int peak shear stress. With initial normal stiffness increasing, it turned out that shear displacement at peak stress and the first peak shear stress increased, however friction angle and friction coefficient showed decrease. In case of shear stiffness and average friction coefficient, it turned out that they are not dependent on the initial normal stress. Minor effects of shear velocity on rough joints were observed in several shear quantities. However, the effects of shear velocity were insignificant regardless of the normal stress increase. Change of shear strength and deformation characteristics on joint roughness were examined, however, it turned out that the variations were attributed to deviation of shear test specimens.
A Study on Notch Bit System for Controlling Blast Vibration and Over-break in Rock Mass
Jeong, Dong-Ho ; Moon, Sang-Jo ; An, Dae-Jin ; Jeong, Won-Joon ; Kim, Eun-Kwan ; Kim, Dong-Gyou ;
Tunnel and Underground Space, volume 17, issue 3, 2007, Pages 216~224
Blasting, using shock and dynamic energy of explosive, is very effective tunnel excavation method. But it had serious problem which is the blast vibration and over-break. In recent study, pre-cracked excavation method using notch hole reduced blast vibration and over-break in tunnel, so we performed study about developing notch bit system for making notch hole. In order to make notch hole effectively we had perform drilling experiments changing length and height of notch and in order to improve speed and precision of drilling we had developed notch bit system which consists of drilling bit, notch bit, adapter and notch guide.
Improvement of Tunnelling Speed in Full-Face Mechanical Excavation
Park, Chul-Whan ; Park, Chan ; Cheon, Dae-Sung ; Synn, Joong-Ho ;
Tunnel and Underground Space, volume 17, issue 3, 2007, Pages 225~233
Because of Norwegian topography as valleys and fjords, a large number of tunnels has been built and 59 of them have been excavated by TBM for last 30 years. Prognosis technology has been developed and improved through lots of TBM experiences, and the NTNU prediction model has been completed. This paper focuses the improvement of net penetration rate and advance rate in 14 Norwegian and 4 Koran TBM tunnelling sites of which data were reported. Through this period, net penetration rate as well as advance rate were increased to double with the improvement of disc cutter size and cutter arrangement in Norway. These rates in Korea were also increased for 15 years even though the rates were lower compared to Norwegian. It is estimated that these low rates were mainly caused by using disc cutters less than 17 inch diameter. It is expected that net penetration rate and advance rate can be increased by improvement of machine and tunnelling technology, especially by using 17 or 19 inch of the disc cutter size in the Korean full face mechanical tunnelling site.
Calculation of Equivalent Block Permeabilities using HydroDFN Model Analysis in Jointed Rocks
Kim, Hyung-Mok ; Ryu, Dong-Woo ; Shin, Hee-Soon ; Tanaka, Tatsuya ; Park, Eui-Seop ;
Tunnel and Underground Space, volume 17, issue 3, 2007, Pages 234~243
In this paper, it was aimed to enhance core processes required in establishing hydrogeological models constructed using borehole investigation results. Water Conducting Feature(WCF) information was extracted from borehole investigation, and HydroDFN model was constructed based on the WCF information. The HydroDFN model was sub-divided by cubic blocks, and equivalent permeability of each sub-divided block was calculated and compared with the results of hydraulic test at the borehole. Through these analysis processes, suggestion for identifying and prescribing WCF parameters in the construction of HydroDFN model was made.