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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 24, Issue 6 - Dec 2014
Volume 24, Issue 5 - Oct 2014
Volume 24, Issue 4 - Aug 2014
Volume 24, Issue 3 - Jun 2014
Volume 24, Issue 2 - Apr 2014
Volume 24, Issue 1 - Feb 2014
Selecting the target year
A Study on the Failure Cause of Large Scale Rock Slope in Limestone Quarries
Lee, Sang-Eun ; Kim, Hak-Sung ; Jang, Yoon-Ho ;
Tunnel and Underground Space, volume 24, issue 4, 2014, Pages 255~274
DOI : 10.7474/TUS.2014.24.4.255
The target of this study is large scale rock slope collapsed by around 7 pm on August, 2012, which is located at
limestone quarries of Gangneung city, Gangwondo. The slope prior to the collapse is formed as the height of about 200 m and the average inclination of
. The estimated amount of the collapse is about
with respect to the slope after the collapse. Geotechnical and field investigations such as boring, geophysical prospecting, surface geological survey, geological lineaments, borehole imaging, metric 3D imaging, experimental and field test, mining work by year, and daily rainfall were performed to find the cause of rock slope failure. Various analyzes using slope mass rating, stereonet projection, limit equilibrium method, continuum and non-continuum model were conducted to check of the stability of the slope. It is expected that the cause of slope failure from the results of various analysis and survey is due to the combined factors such as topography, rainfall, rock type and quality, discontinuities, geo-structural characteristics as the limestone cavity and fault zones, but the failure of slope in case of the analysis without the limestone cavity is not occurred. Safe factor of 0.66 was obtained from continuum analysis of the slope considering the limestone cavity, so the ultimate causes of slope failure is considered to be due to the influence of limestone cavity developed along fault zone.
A Study on Design Criteria of Rockfall Protection Fence Considering Reliability Index
Suk, JaeWook ; Lee, JongGun ; Kim, YongSoo ; Moon, JoonShik ;
Tunnel and Underground Space, volume 24, issue 4, 2014, Pages 275~281
DOI : 10.7474/TUS.2014.24.4.275
The performance criteria of rockfall protection fence and reliability index were investigated considering characteristic of rockfall energy occurred at 160 cut slopes in national highway. As a result of study on statistic of variables that decide rockfall energy using Monte-Carlo simulation, the degree of slope was normal distribution type, mass of rockfall and height of slope was lognormal distribution type. The rockfall energy follows lognormal distribution because of statistical characteristic of mass of rockfall. The reliability index of rockfall protection fence was 0.678 and the failure probability of was very high as 24.9%. Proposed performance criteria of rockfall protection fence considering the scale of domestic rockfall energy is maximum 500 kJ and the range of reliability index was from 1.028 to 1.956. the failure probability of rockfall protection fence was from 14.8 to 2.5 percent if applying the performance criteria using the reliability index.
A Case Study of Prediction and Analysis of Unplanned Dilution in an Underground Stoping Mine using Artificial Neural Network
Jang, Hyongdoo ; Yang, Hyung-Sik ;
Tunnel and Underground Space, volume 24, issue 4, 2014, Pages 282~288
DOI : 10.7474/TUS.2014.24.4.282
Stoping method has been acknowledged as one of the typical metalliferous underground mining methods. Notwithstanding with the popularity of the method, the majority of stoping mines are suffering from excessive unplanned dilution which often becomes as the main cause of mine closure. Thus a reliable unplanned dilution management system is imperatively needed. In this study, reliable unplanned dilution prediction system is introduced by adopting artificial neural network (ANN) based on data investigated from one underground stoping mine in Western Australia. In addition, contributions of input parameters were analysed by connection weight algorithm (CWA). To validate the reliability of the proposed ANN, correlation coefficient (R) was calculated in the training and test stage which shown relatively high correlation of 0.9641 in training and 0.7933 in test stage. As results of CWA application, BHL (Length of blast hole) and SFJ (Safety factor of Joint orientation) show comparatively high contribution of 18.78% and 19.77% which imply that these are somewhat critical influential parameter of unplanned dilution.
Stability Analysis for Ground Uplift in Underground Storage Caverns for High Pressurized Gas using Hoek-Brown Strength Criterion and Geological Strength Index (GSI)
Kim, Hyung-Mok ;
Tunnel and Underground Space, volume 24, issue 4, 2014, Pages 289~296
DOI : 10.7474/TUS.2014.24.4.289
A simple analytical approach for stability assessment of underground storage caverns against ground uplift of overburden rock above the rock caverns for high pressurized fluid such as compressed air energy storage (CAES) and compressed natural gas (CNG) was developed. In the developed approach, we assumed that failure plane of the overburden is straight upward to ground surface, and factor of safety can be calculated from a limit equilibrium analysis in terms of this cylindrical shape failure model. The frictional resisting force on the failure plane was estimated by Hoek-Brown strength criterion which replaces with Mohr-Coulomb criterion such that both intact rock strength and rock mass conditions can be considered in the current approach. We carried out a parametric sensitivity analysis of strength parameters under various rock mass conditions and demonstrated that the factor of safety againt ground uplift was more sensitive to Mohr-Coulomb strength criterion rather than Hoek-Brown criterion.
Stability Analysis of Multiple Thermal Energy Storage Caverns Using a Coupled Thermal-Mechanical Model
Kim, Hyunwoo ; Park, Dohyun ; Park, Eui-Seob ; Sunwoo, Choon ;
Tunnel and Underground Space, volume 24, issue 4, 2014, Pages 297~307
DOI : 10.7474/TUS.2014.24.4.297
Cavern Thermal Energy Storage system stores thermal energy in caverns to recover industrial waste heat or avoid the sporadic characteristics of renewable-energy resources, and its advantages include high injection-and-extraction powers and the flexibility in selecting a storage medium. In the present study, the structural stability of rock mass pillar between these silo-type storage caverns was assessed using a coupled thermal-mechanical model in
. The results of numerical simulations showed that thermal stresses due to long-term storage depended on pillar width and had significant effect on the pillar stability. A sensitivity analysis of main factors indicated that the influence on the pillar stability increased in the order cavern depth < pillar width < in situ condition. It was suggested that two identical caverns should be separated by at least one diameter of the cavern and small-diameter shaft neighboring the cavern should be separated by more than half of the cavern diameter. Meanwhile, when the line of centers of two caverns was parallel to the direction of maximum horizontal principal stress, the shielding effect of the caverns could minimize an adverse effect caused by a large horizontal stress.
An Experimental Study on Smoke Movement by the External Wind in Road Tunnel Fires
Lee, Sung-Ryong ;
Tunnel and Underground Space, volume 24, issue 4, 2014, Pages 308~315
DOI : 10.7474/TUS.2014.24.4.308
In this study, reduced scale experiments were carried out to evaluate the effect of external wind in a road tunnel fire. Experiments were conducted in a
tunnel. 4.5 litter gasoline was used as a fuel. Temperature, oxygen and carbon monoxide concentration were measured. Smoke reaching time to the tunnel exit was affected by the external wind. When a fire was fully developed, wind effect is reduced compared with the early stage of a fire. CO concentration was reached at more than 1,500 ppm.
Development of an Earthquake-Resistant Model for a High-Level Waste Disposal Canister
Choi, Young-Chul ; Yoon, Chan-Hoon ; Kim, Hyun-Ah ; Choi, Heui-Joo ;
Tunnel and Underground Space, volume 24, issue 4, 2014, Pages 316~324
DOI : 10.7474/TUS.2014.24.4.316
In the underground 500 m depth, the high level radioactive waste disposal system is made by boring the tunnel in the base rock and putting the high level waste disposal canister that is the surrounding form with the buffer material. According to the many statistics, it is the tendency that the earthquake increases in the Korean peninsula every year. In case that the earthquake is generated, the disposal canister in the rock mass can be broken due to the shearing force in the underground. Furthermore, a major environmental problems can be caused by the radioactive harmful substances. In this study, the earthquake-proof type buffer material was developed with the protection method safely on the earthquake. The main parameter having an effect on the earthquake-resistant performance was analyzed and the earthquake-proof type buffer material was designed. The shear analysis model was developed and the performance of the earthquake-proof type buffer material was evaluated by using ABAQUS.
Comparisons of Brittleness Indices of Shale and Correlation Analysis for the Application of Hydraulic Fracturing
Park, Jung-Ah ; Park, Bona ; Min, Ki-Bok ;
Tunnel and Underground Space, volume 24, issue 4, 2014, Pages 325~333
DOI : 10.7474/TUS.2014.24.4.325
Hydraulic fracturing is the key technology for production of shale gas, which is one of the major unconventional resources. Brittleness index is one of the most important mechanical properties which determine the efficiency of hydraulic fracturing. It was required that the production of shale gas increases with more brittle behavior. Confusingly, there are numerous definitions available for brittleness of rock. This paper summarizes various definitions of brittleness index, and presents correlation analysis of the brittleness indices by using the laboratory experimental results of 48 shale specimens in Korea. Generally, it shows a very weak positive correlation between the brittleness index (
) which is the ratio of uniaxial compressive strength to tensile strength and the brittleness index (
) which is calculated by using the Youngs modulus and Poisson's ratio. In addition, the role of Poissons ratio is not clear in defining brittleness indices. In conclusion, standardization of definition for brittleness index is required to apply it to hydraulic fracturing as a parameter for predicting the efficiency.