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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 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
A Case Study on the Application of Self Supporting Air Tube
Lee, Shin ; Kang, Dea-Woo ;
Tunnel and Underground Space, volume 17, issue 4, 2007, Pages 248~254
Already, the air deck blasting method has been used to take many advantages of blasting. In the existing air deck blasting method, air deck is made usually on column charge. But in the case study, we analyzed about the effect of self supporting air tube which made air deck in column charge. As results of this case study, it was shown that blasting vibration was decreased about
and quantity of explosive was decreased about
. Also, fragmentation was shown to be smaller than it of common blasting method.
A Case Study on Reinforcement of Ground and Foundation against Subsidence in Abandoned Mining Area
Kim, Do-Hyung ; Choi, Chang-Rim ; Kim, Dong-Hyun ; Lee, Du-Hwa ; Lee, Baek-Song ; Je, Hae-Chan ;
Tunnel and Underground Space, volume 17, issue 4, 2007, Pages 255~265
As the mechanism and effect range of subsidence are altered according to the various conditions (the ground condition, the earth pressure, the geometric condition of underground cavity and the structure load), the analysis and prediction of subsidence in abandoned mining area are very difficult. Also, as the geological characteristics and the mining methods are differed in each mines, the application of the pre-existing reinforcements without improvement has a lot of difficulties and limits. In this study, the various underground investigation such as long-depth core drilling, seismic tomography and BIPS (borehole image processing system) were performed, the distribution of underground cavity and coal seam and rock relaxation condition were analyzed. And we predicted the type of subsidence and estimated the subsidence by theories of mining subsidence. With these results, we analyzed the mechanism of subsidence occurrence in the research object area. Finally, we improved existing methods which were applied to the abandoned mining area and also we established the rational reinforcement for the ground and structure foundation against each subsidence cause.
Performance Improvement and Durability Evaluation of Shotcrete for Permanent Tunnel Support
Lee, Sang-Pil ; Ryu, Jong-Hyun ; Lee, Sang-Don ; Jeon, Seok-Won ; Lee, Chung-In ;
Tunnel and Underground Space, volume 17, issue 4, 2007, Pages 266~284
Recently, many efforts have been made to construct the first unlined tunnel, without in-situ concrete lining, in Korea. However, the lack of reliability in the performance of shotcrete as permanent tunnel support prevented from its realization. Shotcrete has been regarded to have significant problems in field application and long term performance because of unsatisfactory strength level and durability compared to those of European countries. In this study, the high strength shotcrete satisfying compressive strength over 40 MPa and flexural strength over 4.5 MPa was developed from optimized mix design. The type of accelerators and the amount of silica fume were selected as the main factors in mixing process and the analyses were carried out up to the elapsed time of 2 years. In order to evaluate the short term durability of shotcrete, an array of laboratory test consisting of freeze-thaw, carbonation chloride penetration and permeability test was performed. For long-term durability tests, specimens have been put in an operated highway tunnel to expose them to the similar environment when they are actually used as an unlined tunnel support. From the strength and durability tests, it was found that only alkali-free based accelerator satisfied the target strength of this study and also, the developed shotcrete showed very high performance in its durability.
A Study on Numerical Technique to Enhance In-Situ Applicability and to Overcome Uncertainty in Geo-Material Properties
Kim, Hyung-Mok ; Synn, Joong-Ho ; Inoue, Junya ;
Tunnel and Underground Space, volume 17, issue 4, 2007, Pages 285~294
Material properties of geomaterials are usually heterogeneous. And the limitted number of investigation for the subsurface material properties in terms of boreholes are not sufficient enough for identifying the heterogeneity. In most civil engineering work, pre-investigation results can be different from those by in-situ inspection during the construction work. With these points of view, a new analysis concept aiming to evaluate the uncertainty resulted from the heterogeneity of the geomaterial properties as well as to enhance a construction workability and design qualify by a prompt feedback of in-situ conditions was proposed. It was accomplished by linking the Element Free analysis and pre-developed stochastic methods represented by Karhunen-Loeve expansion. Simple ID problem was solved by the developed method, and its validity as well as the characteristic results by different stochastic methods were clarified.
Detonating Cord as a Controllable Source for Scaled Model Blasting Test
Yang, Hyung-Sik ; Kim, Jong-Gwan ; Choi, Mi-Jin ; Choi, Byung-Hee ; Ryu, Chang-Ha ;
Tunnel and Underground Space, volume 17, issue 4, 2007, Pages 295~300
A method using detonating cord was suggested to control the blasting source for scaled model test. Blasting of 5 concrete block was carried out to verify the method. It was proved that blasting power can be controlled by suggested method. It seemed to be reasonable to use the reduction ratio based on the explosion heat.
Temperature Prediction of Underground Working Place Using Artificial Neural Networks
Kim, Yun-Kwang ; Kim, Jin ;
Tunnel and Underground Space, volume 17, issue 4, 2007, Pages 301~310
The prediction of temperature in the workings for the propriety examination for the development of a deep coal bed and the ventilation design is fairly important. It is quite demanding to obtain precise thermal conductivity of rock due to the variety and the complexity of the rock types contiguous to the coal bed. Therefore, to estimate the thermal conductivity corresponding to this geological situation and complex gallery conditions, a computing program which is TemPredict, is developed in this study. It employs Artificial Neural Network and calculates the climatic conditions in galleries. This advanced neural network is based upon the Back-Propagation Algorithm and composed of the input layers that are acceptant of the physical and geological factors of the coal bed and the hidden layers each of which has the 5 and 3 neurons. To verify TemPredict, the calculated result is compared with the measured one at the entrance of -300 ML 9X of Jang-sung production department, Jang-sung Coal Mine. The difference between the results calculated by TemPredict (
) and measured (
) is only
, which is less than the allowable error 5%. The result has more than 95% of very high reliability. The temperature prediction for the main carriage gallery 9X in -425 ML under construction when it is completed is made. Its result is
. In the future, it would contribute to the ventilation design for the mine and the underground structures.
The extent and depth of brittle failure around circular tunnel with stress conditions
Cheon, Dae-Sung ; Park, Chul-Whan ; Jeon, Seok-Won ; Park, Chan ;
Tunnel and Underground Space, volume 17, issue 4, 2007, Pages 311~321
Failure of underground structures in hard rocks is a function of the in-situ stress, the intact rock strength and the distribution of fractures in the rock mass. At highly stressed regime, brittle failure is often observed due to excavation-induced stress. The characteristics of brittle failure are classified as failure grade, failure initiation stress, extent of failure and depth of failure. For safety construction of underground structures, these characteristics of brittle failure with stress conditions should be understood. In this study we evaluated the relationship between the extent and depth of failure with stress conditions for failure happened model specimens through true triaxial model experiments. The extent and depth of failure were determined using visual observation and computed tomography (CT). The results indicate that the depth of failure was affected by differential stress perpendicular to the axis of tunnel. However the extent of failure was irrelevant to the stress conditions.
Development of Practical Rock Slope Hazard Evaluation Method
Jung, Yong-Bok ; SunWoo, Choon ; Lee, Byung-Joo ; Song, Won-Kyong ;
Tunnel and Underground Space, volume 17, issue 4, 2007, Pages 322~331
Hundreds of rock slopes are constructed along the road, highway and railroad in mountainous Kangwon province and managed by each authorities concerned. It is practically not possible to carry out detailed rock slope investigation owing to the tremendous number of slopes and budgetary limit. Therefore, it is reasonable to perform a step-by-step investigation consisted of basic and detailed survey program and practical rock slope hazard assesment method for person in charge is strongly required. Through the development and application of KSMR (Korean Slope Mass Rating), it was found that KSMR could be practically used as an alternative of SMR though the number of inputs were reduced. In addition, the difference of hazard assessment between KSMR and experts decreased in case of considering the height of slope.