• International Journal of Highway Engineering
• /
• v.12 no.1
• /
• pp.9-20
• /
• 2010

This study was intended to identify, among various characteristics of tunnel, the relationship between the design factors comprising the driver's psychological stability, easiness and the sensitivity and then to suggest the mechanism for evaluating the tunnel view, and to that end, the study attempted to evaluate the relations between the physical elements comprising the tunnel shape and the variation of driver's emotional recognition, thereby proposing the measures to create the scenic environment. As a result of LISREL modeling to identify the characteristics of emotional recognition to tunnel view, the elements affecting tunnel view appeared to be emotional image created by the combination of elements comprising the tunnel view. Such emotional image can be explained by design elements and individual characteristics, and the effect of design element appeared to be greater than individual characteristics. The relations between individual characteristics and design element appeared to be positive (+) and the relations between the "safety" and "variability" was significant. And the "safety" have had greater effect on view recognition than "variability", indicating that the drivers tend to give more importance to "safety", but also require the "variability"on the other hand.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.03a
• /
• pp.571-576
• /
• 2010

In this study, an application method of critical strains concept for tunnels' safety by using the values of measured displacements which are obtained in the field is discussed. The aim 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.

• Journal of the Korean Arthroscopy Society
• /
• v.2 no.2
• /
• pp.135-140
• /
• 1998

From 1989 to 1994, authors have reconstructed the posterior cruciate ligament(PCL) in 51 knees with an autogenous central one-third of the patellar tendon by transtibial two tunnel technique, but there were not a few cases of unfavorable results. So from January 1995, we have reconstructed the PCL deficient knees by "modified tibial inlay technique" to avoid the grafted tendon abrasion at the posterior opening of the tibial tunnel(killer turn). Purpose of this study was to compare the results of two surgical techniques and what its advantages and disadvantages are. We could follow up 39 cases of transtibial two tunnel techique group(group A) more than one year, average being 23.7 months and 21 cases of modified tibial inlay technique group(group B) more than 12 months, average being 14.7 months. The clinical results were evaluated by the OAK knee scoring system ($M{\ddot{u}}ller$'s criteria) and the posteror stress roentgenography (push view) with Telos stress device compared with the uninjured knees. The arthroscopic second-look findings were also evaluated. In group A : The $M{\ddot{u}}ller$'s knee score was average 80.1 points, the posteror displacement in push view was average 4.4mm at the last follow up. There were 17 cases(44%) of unfavorable results which showed unstable posterior displacement more than 4mm compared with the uninjured knee in push view. Among the 19 cases of arthroscopic second look examinations, nearly normal PCL appearances of the grafted tendons were noted only in 9 cases(47%). In group B : The $M{\ddot{u}}ller$'s knee score was average 86.7 points, the posterior displacemnet in push view was average 3.6mm at the last follow up. There were 5 cases(23.8%) of unfavorable results which showed unstable posterior displacement more than 4mm compared with the uninjured knee in push view but 4 out of 5 cases showed 6mm posterior displacement in push views. Among the 7 cases of arthroscopic second-look examinations, 6 cases(86%) showed nearly normal PCL appearances of the grafted tendons. In modified tibial inlay technique of PCL reconstruction, it was easier to pull out the BPTB and in cases of remained laxed meniscofemoral ligament it was easier to preserve the remained structures than transtibial two tunnel technique. We expect the "modified tibial inlay technique" may solve the problem of grafted patellar tendon abrasion at the posterior orifice of tibial tunnel and may contribute to the successful PCL reconstruction.

• Geomechanics and Engineering
• /
• v.22 no.6
• /
• pp.497-507
• /
• 2020

This paper presents the results of a three-dimensional numerical investigation into the effect of new tunnel construction on structural performance of existing tunnel lining. A three-dimensional finite difference model, capable of modelling the tunnel construction process, was adopted to perform a parametric study on the spatial variation of new tunnel location with respect to the existing tunnel with emphasis on the plan crossing angle of the new tunnel with respect to the existing tunnel and the vertical elevation of the new tunnel with respect to the existing one. The results of the analyses were arranged so that the effect of new tunnel construction on the lining member forces and stresses of the existing tunnel can be identified. The results indicate that when a new tunnel underpasses an existing tunnel, the new tunnel construction imposes greater impact on the existing tunnel lining when the two tunnels cross at an acute angle. Also shown are that the critical plan crossing angle of the new tunnel that would impose greater impact on the existing tunnel depends on the relative vertical location of the new tunnel with respect to the existing one, and that the overpassing new tunnel construction scenario is more critical than the underpassing scenario in view of the existing tunnel lining stability. Practical implications of the findings are discussed.

• Journal of the Korean Arthroscopy Society
• /
• v.2 no.2
• /
• pp.114-118
• /
• 1998

We retrospectively evaluated the changes in the diameter of the tibial tunnel over time following the reconstruction of the anterior cruciate ligament with a bone-patella tendon-bone(BPTB) autograft(25 cases) and quadruple semitendinosus(ST) graft(27 cases) in 52 patients at one year postoperatively. The changes in the geometry of the bony tunnel were measured with radiography. The demensions at final follow up were correated with the clinical results. An increased width of the tibial tunnel was noted in all cases. On the femoral side, however, no tunnel expansion was noted. In AP view, the average tibial tunnel enlargement in ST and BPTB graft groups were 1.30mm(13%) and 1.82mm(17%), respectively. In lateral view, the average tibial tunnel enlargement in ST and BPTB graft group was 1.30mm(13%) and 2.04mm(19%). The differences between two groups were not statistically significant, however, there was evidence of a borderline significance(P=0.0502). Although the tunnel enlargement does not appear to adversely affect the clinical outcome in the short term, the exact mechanism which are involved should be demonstrated. Furthermore histologic study is needed to evaluate graft replacements with emphasis on the graft-tunnel interface.

• Proceedings of the SAREK Conference
• /
• 2008.11a
• /
• pp.80-83
• /
• 2008

As SOC (Social Overhead Capital) has been expanded, the highway road construction has been accelerated and city road system has been more complicated. So, long road tunnels have been increased and traffic flow rate also has been raised. Accordingly, the exhausting gas of vehicle cars seriously deteriorates the tunnel inside air quality and driving view. In order to improve tunnel inside air quality, we may need to introduce a compulsory ventilation system as well as natural ventilation mechanism. The natural ventilation mechanism is enough for short tunnels, meanwhile longer tunnels require a specific compulsory ventilation facility. Many foreign countries already have been devoting on development of effective tunnel ventilation system and especially, some European nations and Japan have already applied their developed tunnel ventilation system for longer road tunnels. More recently, as the quality of life improved, our concerns about safety of driving and better driving environment have been increased. In order to obtain clearer and longer driving view, we are more interested in EP tunnel ventilation system in order to remove floating contaminants and automobile exhaust gas. Evan though it's been a long time since many European countries and Japan applied more economical and environment-friendly tunnel ventilation system with their self-developed Electrostatic Precipitator, we are still dependant on imported system from foreign nations. Therefore, we need to develop our unique technical know-how for optimum design tools through validity investigation and continuous possibility examination, eventually in order to localize the tunnel ventilation system technology. In this project, we will manufacture test-run products to examine the performance of system in order to develop main parts of tunnel ventilation system such as electrostatic precipitator, high voltage power generator, water treatment system, etc.

• Proceedings of the SAREK Conference
• /
• 2009.06a
• /
• pp.1238-1243
• /
• 2009

As Social Overhead Capital(SOC) has been expanded, the highway road construction has been accelerated and city road system has been more complicated. So, long road tunnels have been increased and traffic flow rate also has been raised. Accordingly, the exhausting gas of vehicle cars seriously deteriorates the tunnel inside air quality and driving view. In order to improve tunnel inside air quality, it is needed to introduce a compulsory ventilation system as well as natural ventilation mechanism. The former, that is, a special compulsory ventilation facility is very useful and helpful to prevent a tunnel of being contaminated by traffic in most case. In the case of obtaining clearer and longer driving view, the ventilation systems have to be considered in order to remove floating contaminants or exhaust gas from engines. In this paper, discharge electrode design technology will be discussed.

• International Journal of Highway Engineering
• /
• v.18 no.2
• /
• pp.19-27
• /
• 2016

PURPOSES: The behavior of a concrete pavement in a tunnel was investigated, based on temperature data obtained from the field and FEM analysis. METHODS: The concrete pavement in a tunnel was evaluated via two methods. First, temperature data was collected in air and inside the concrete pavement both outside and inside the tunnel. Second, FEM analysis was used to evaluate the stress condition associated with the slab thickness, joint spacing, dowel, and rock foundation, based on temperature data from the field. RESULTS : Temperature monitoring revealed that the temperature change in the tunnel was lower and more stable than that outside the tunnel. Furthermore, the temperature difference between the top and bottom of the slab was lower inside the tunnel than outside. FEM analysis showed that, in many cases, the stress in the concrete pavement in the tunnel was lower than that outside the tunnel. CONCLUSIONS : Temperature monitoring and the behavior of the concrete pavement in the tunnel revealed that, from an environmental point of view, the condition in the tunnel is advantageous to that outside the tunnel. The behavior in the tunnel was significantly less extreme, and therefore the concrete pavement in the tunnel could be designed more economically, than that outside the tunnel.

• International Journal of Highway Engineering
• /
• v.18 no.2
• /
• pp.11-18
• /
• 2016

PURPOSES: This paper investigates behavior and performance of concrete pavement in tunnel based on temperature data from field. METHODS : In this study, there are 4 contents to evaluate concrete pavement in tunnel, First, Comparison for distress was conducted at outside, transition, and inside part of tunnel. Secondly, temperature data was collected in air and inside concrete pavement in outside and inside tunnel. Thirdly, FEM analysis was performed to evaluate stress condition, based on temperature data from field. Finally, performance prediction was done with KPRP program. RESULTS: From the distress evaluation, failure of inside tunnel was much less than it of outside tunnel, Temperature change in tunnel was less than out side, and also it was more stable. According to result of FEM analysis, both curling stress status of inside tunnel was lower than it of outside tunnel. Based on KPRP program analysis, performance of inside tunnel was longer than outside. CONCLUSIONS : Through all study about behavior and performance of concrete pavement in tunnel, condition in tunnel has more advantages from environmental and distress point of view. Therefore, performance of inside tunnel was better than outside.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.11 no.4
• /
• pp.403-410
• /
• 2009

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.