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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Korean Tunnelling and Underground Space Association
Journal Basic Information
Journal DOI :
Korean Tunnelling and Underground Space Association (KTA)
Editor in Chief :
Volume & Issues
Volume 11, Issue 4 - Dec 2009
Volume 11, Issue 3 - Sep 2009
Volume 11, Issue 2 - Jun 2009
Volume 11, Issue 1 - Mar 2009
Selecting the target year
Brittle rock property and damage index assessment for predicting brittle failure in underground opening
Lee, Kang-Hyun ; Bang, Joon-Ho ; Kim, Jin-Ha ; Kim, Sang-Ho ; Lee, In-Mo ;
Journal of Korean Tunnelling and Underground Space Association, volume 11, issue 4, 2009, Pages 327~351
Laboratory tests are performed in this paper to investigate the brittle failure characteristics of over-stressed rocks taken in deep depth. Also, numerical simulation performed using that the so-called CWFS(Cohesion Weakening Frictional Strengthening) model is known to predict brittle failure phenomenon reasonably well. The most typical rock types of Korean peninsula - granite and gneiss - were used for testing. Results of uniaxial compression tests showed that the crack initiation stress was about 41 % to 42% of the uniaxial compressive strength regardless of rock types, where as, the crack damage stress of granite was about 75%, and that of gneiss was about 97%. Through the damage-controlled test, strength parameters of each rock were obtained as a function of damage degree. After the peak, the crack damage stress and the maximum stress were decreased, The cohesion was decreased and the friction angle was increased with increase of rock damage. Before reaching the peak, the elastic modulus was slightly increased, while decreased after the peak. Poisson's ratio was increased as the damage of rock proceeds. Comparison of uniaxial compression tests and damage-controlled tests shows the crack initiation stress estimated from the damage-controlled test fluctuated within the range of crack initiation stress obtained from the uniaxial compression test; the crack damage stress was less than that estimated from the uniaxial compression test. In order to predict the critical depth that brittle failure occurs, numerical simulations using the CWFS model were performed for an example site. Material parameters obtained from the laboratory tests mentioned above were used for CWFS simulation. Comparison between the critical depth predicted from the numerical simulation using the CWFS model and that predicted by using the damage index proposed by Martin et al.(l999), showed that critical depth cannot be reasonably predicted by the currently used damage index except for circular tunnels. A modified damage index was proposed by the author which takes the shape of tunnels other than circular into account.
A study on comparison of a ground water influx quantity in Seoul subway tunnel
Woo, Jong-Tae ;
Journal of Korean Tunnelling and Underground Space Association, volume 11, issue 4, 2009, Pages 353~359
As ground water influx quantity which flows into the tunnel inside from the 7.937 km section of Han River and small and 7 medium-sized rivers which pass through subway line 5 is average
and it's 55.3% of the underground water influx quantity
which flows into whole tunnel section 31.29 km. If we suppressed the underground water influx from the rivers, it would be expect that the maintenance and management expenses would be able to reduce a lot. In addition, as the result of investigating the difference between the ground water influx quantity which flows into the river section and that of the design standard, the ground water influx quantity is
and it is flowing to similar level of tunnel design standard
. However, when it is compared with tunnel average influx quantity
, it has been found that 2.18 times of ground water flows into rivers.
Time-lapse inversion of resistivity tomography monitoring data around a tunnel
Cho, In-Ky ; Jeong, Jae-Hyeung ; Bae, Gyu-Jin ;
Journal of Korean Tunnelling and Underground Space Association, volume 11, issue 4, 2009, Pages 361~371
Resistivity tomography is very effective geophysical method to find out the resistivity distribution and its change in time around a tunnel. Thus, the resistivity tomogram can provide helpful information which is necessary for the effective maintenance of the tunnel. However, an air filled tunnel severely distorts tomography data, especially when the current or potential electrode is placed near the tunnel. Moreover, the distortion can often lead to misinterpretation of tomography monitoring data. To solve these problem, we developed a resistivity modeling and time-lapse inversion program which include a tunnel. In this study, using the developed program we assured that the inversion including a tunnel gives much more accurate image around a tunnel, compared with the conventional tomogram where the tunnel is not included. We also confirmed that the time-lapse inversion of resistivity monitoring data defines well resistivity changed areas around a tunnel in time.
Quantitative preliminary hazard level simulation for tunnel design based on the KICT tunnel collapse hazard index (KTH-index)
Shin, Hyu-Soung ; Kwon, Young-Cheul ; Kim, Dong-Gyou ; Bae, Gyu-Jin ; Lee, Hong-Gyu ; Shin, Young-Wan ;
Journal of Korean Tunnelling and Underground Space Association, volume 11, issue 4, 2009, Pages 373~385
A new indexing methodology so called KTH-index was developed to quantitatively evaluate a potential level for tunnel collapse hazard, which has been successfully applied to tunnel construction sites to date. In this study, an attempt is made to apply this methodology for validating an outcome of tunnel design by checking the variation of KTH-index along longitudinal tunnel section. In this KTH-index simulation, it is the most important to determine the input factors reasonably. The design factor and construction condition are set up based on the designed outcome. Uncertain ground conditions are arranged based on borehole test and electro-resistivity survey data. Two scenarios for ground conditions, best and worst scenarios, are set up. From this simulation, it is shown that this methodology could be successfully applied for providing quantitative validity of a tunnel design and also potential hazard factors which should be carefully monitored in construction stage. The hazard factors would affect sensitively the hazard level of the tunnel site under consideration.
Characterization of deterioration of concrete lining in tunnel structures
Kim, Dong-Gyou ; Jung, Ho-Seop ; Bae, Gyu-Jin ; Shin, Hyu-Soung ;
Journal of Korean Tunnelling and Underground Space Association, volume 11, issue 4, 2009, Pages 387~394
The objective of this study is to evaluate the durability and deterioration of concrete lining in the seven conventional tunnels. These tunnels were constructed about 40~70 years ago, and closed about 10~40 years ago. The field investigation and various laboratory testings were performed for this study. It was observed from the visual, examinations that the concrete linings of 7 tunnels were severely deteriorated, such as, cracks, leakages, desquamation, and exploitations. The compressive strengths obtained from rebound hardness method and uniaxial compressive strength test on core specimens largely differed depending on the locations in the tunnel. The maximum compressive strength of concrete lining was greater about 2 times than the minimum compressive strength of concrete lining in the same tunnel. The results of micro-structural analysis showed that the substances deteriorating the concrete lining, such as ettringite and thaumasite, were detected in the concrete lining of tunnel.
A case study for prediction of the natural ventilation force in a local long vehicle tunnel
Lee, Chang-Woo ; Kim, Sang-Hyun ; Gil, Se-Won ; Cho, Woo-Chul ;
Journal of Korean Tunnelling and Underground Space Association, volume 11, issue 4, 2009, Pages 395~401
One of the key design factors for the ventilation and safety system at extra long tunnel is the airflow velocity induced by the natural ventilation force. Despite of the importance, it has not been widely studied due to the complicated influencing variables and the relationship among them is difficult to quantify. At this moment none of the countries in the world defines its specific value on verified ground. It is also the case in Korea. The recent worldwide disasters by tunnel fires and demands for better air quality inside tunnel by users require the optimization of the tunnel ventilation system. This indicates why the natural ventilation force is necessary to be thoroughly studied. This paper aims at predicting the natural ventilation force at a 11 km-long tunnel which is in the stage of detailed design and will be the longest vehicle tunnel in Korea. The concept of barometric barrier which can provide the maximum possible natural ventilation force generated by the topographic effect on the external wind is applied to estimate the effect of wind pressure and the chimney effect caused by the in and outside temperature difference is also analyzed.
Engineering interpretation of critical strains in the ground based on the tunnel engineering
Shin, Yong-Suk ; Park, Si-Hyun ;
Journal of Korean Tunnelling and Underground Space Association, volume 11, issue 4, 2009, Pages 403~410
This paper discusses an application method of critical strains concept for tunnels' safety by using the values of measured displacements which are obtained in the field. The aim of this paper is to: (1) study on the engineering meanings of critical strains concept by reviewing the previous researches and application examples with measured displacement values; (2) study on the engineering reasonability of critical strains concept with the view point of a tunnel engineering and a geotechnical engineering; (3) study on the features of ground deformation due to tunneling and reciprocal relation between total displacement and measured displacement; (4) evaluate a tunnel safety by using domestic measurements collected in the field; and (5) re-evaluate the control criteria which were previously used in the field, with the view point of critical strains concept. Consequently, it was confirmed that critical strains in the ground has a reasonability and a possibility of unified or common concept with the view point of a tunnel engineering.
Experimental study on vehicle-induced unsteady flow in tunnel
Kim, Jung-Yup ; Shin, Hyun-Joon ;
Journal of Korean Tunnelling and Underground Space Association, volume 11, issue 4, 2009, Pages 411~417
The thermo-flow field in road tunnel is influenced by some facts such as piston effect of vehicle's move, operation of ventilation facilities, natural wind and buoyancy effect of fire plume. Among those, piston effect is one of primary causes for formation of air flow in road tunnel and has an effect on initial direction of smoke flow in tunnel fire. In this study to analyze the unsteady flow in the tunnel caused by the run of vehicle, the experimental study of vehicle-induced unsteady flow on a reduced-scale model tunnel is presented. While the three types of vehicle shape such as basic type of rectangular shape, diamond-head type and stair-tail type are changed, the pressure and air velocity variations with time are measured. The rising ratio of pressure and velocity are in order of "basic type of rectangular shape > stair-tail type > diamond-head type". The experimental results would be good data for development of a numerical method on the vehicle-induced unsteady tunnel flow.
Behavior of Braced Rib Arch in Shallow Tunnel Excavated by Semi-Cut and Cover Method
An, Joung-Hwan ; Lee, Sang-Duk ;
Journal of Korean Tunnelling and Underground Space Association, volume 11, issue 4, 2009, Pages 419~425
Recently, the number of shallow tunnel construction increases to improve the structural safety and environment-friendliness. In Semi-Cut and Cover Method, ground is excavated to the crown arch level and braced rib arch is set to backfill before the excavation of lower face. Semi-Cut and Cover Method is proposed to solve the problems occurred by the conventional Cut and Cover Method, such as unstability, high-cost and the large cutting slope to be reinforced. In this paper, the behaviors of Braced Rib Arch in shallow tunnel excavated by semi-cut and cover method was studied. Model tests in 1:10 Scale were performed in real construction sequences. The distance between supports of rib arch was 1.8 m and the length of spacer was 1.0 m. the size of test pit was 4.0 m (width)
3.3 m (length) 4.0 m (height) in dimension. Tests results show that backfill load acting on arch was smaller than that in the conventional Open-Cut Method.
An analytical solution for soil-lining interaction in a deep and circular tunnel
Lee, Seong-Won ; Jeong, Jea-Hyeung ; Kim, Chang-Yong ; Bae, Gyu-Jin ; Lee, Joo-Gong ; Park, Kyung-Ho ;
Journal of Korean Tunnelling and Underground Space Association, volume 11, issue 4, 2009, Pages 427~435
This study deals with the analytical solution for soil-lining interaction in a deep and circular tunnel. Simple closed-form analytical solutions for thrust and moment in the circular tunnel lining due to static and seismic loadings are developed by considering the relations between displacement and interaction forces at the soil-lining interface. The interaction effect at the soil-lining interface is considered with new ratios (the normal and shear stiffness ratios). The effects of the ratios on the normalized thrust and the normalized moment are investigated.
The control method for axial cracks on NATM tunnel linings
Zheng, Xiu-Mei ; Park, Inn-Joon ;
Journal of Korean Tunnelling and Underground Space Association, volume 11, issue 4, 2009, Pages 437~447
It is easily found by several references of NATM that the cracks on the lining concrete of NATM are more developed than those of the conventional tunnel methods. Based on the results of research, the new method is proposed to control and protect the axial cracks on the tunnel linings. Also, the efficiency of proposed method is evaluated using the Distinct Element Method.