• International Journal of Highway Engineering
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• v.18 no.2
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• pp.19-27
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• 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
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• v.18 no.2
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• pp.11-18
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• 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.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1993.10a
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• pp.32-37
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• 1993

A method of tunnel analysis for a new type of tunnel construction method (ACLCM, Automatic Concrete Lining Construction Method) is presented here. ACLCM is an unique tunnel construction method which provides concrete lining at the end of shield machine by extruding concrete into the space between the excavated ground surface and the inner form (Automatic Concrete Lining Machine). Since behaviors of tunnel and the surrounding soils are greatly influenced by the construction method, existing tunnel design methods may not be applicable to the design of ACLCM tunnel. In this study, a method of ACLCM tunnel analysis is suggested to provide the prediction of behavior of ACLCM tunnel and surrounding soils as well as to check up the safety during the construction and after the completion of ACLCM tunnel

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.4
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• pp.139-147
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• 2003

The most tunnel damage such as cracks or leakage which exist in tunnel lining commonly, is caused by the voids where exist behind the tunnel lining, through the tunnel safety inspections. These voids were analysed to affect to a stability of a running-tunnel seriously. The aim of this paper is to develope the lightweight foam concrete for tunnel backfilling material using stone-dust of cake state and to apply the lightweight foam concrete developed to the old tunnel. This paper shows the basic properties of lightweight foam concrete mixed with stone-dust including flow rate, unit volume weight, absorption rate and compressive strength. In addition, according to the designed compound ratio, the lightweight foam concrete was applied to the ASSM tunnel for an application assessment. The engineering application of the lightweight foam concrete as the old tunnel's backfilling material was confirmed in this assessment.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.621-628
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• 2005

The concrete lining in tunnel performs structural and nonstructural functions. The concrete lining works as a structural member for released load and residual water pressure in NATM tunnel system. Also concrete lining used for finishing the tunnel surface. The initial crack of concrete lining is reported because of difficulties in construction process, which concrete is injected into 30$\sim$40cm narrow gap between lining form and tunnel surface through 500${\times}$600mm small injection holes in the form. In this paper, we research a reason of initial crack occurrence by the case study of 4 lane wide span tunnel, and propose an improved method for crack minimization in construction process. We verify that the proposed method can give qualified concrete lining by carrying out the concrete injection model test and the numerical analysis of concrete flow.

• International Journal of Highway Engineering
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• v.16 no.3
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• pp.51-57
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• 2014

PURPOSES : This study is to suggest tunnel length to spray curing compound, based on the field tests. METHODS : At first field test, length from the entrance of tunnel to wet wall was checked by visual survey. The second and third test, various sensors were installed in concrete or in tunnel, such as RH sensor, temperature sensor, portable weather station and etc.. And also, test for bleeding and retaining water of concrete were conducted to evaluate environmental effect on concrete pavement. RESULTS : The result of the field experiment for tunnel length to spray curing compound indicates that length changes depending on tunnel length, season, and location. Environmental condition of a short tunnel was not much different between location near entrance and at center of tunnel. However, in case of a medium and long tunnel, effect of outside environmental condition decreased, when location moved into tunnel center of it. CONCLUSIONS : From the testing results, it can be proposed that optimum tunnel length to spray curing compound is 60m for a medium and long tunnel, and whole length for a short tunnel.

• Journal of the Korea Concrete Institute
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• v.20 no.4
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• pp.487-493
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• 2008

Tunnel structures are widely used for transportations in mountains areas. To shorten the construction period and to cut down the construction expenditure, a construction technique that a tunnel excavation process and a tunnel lining process are simultaneously performed is often applied in the field. However, due to the vibration and impact caused by excavation process, cracking and deterioration of tunnel lining concrete could happen. This research experimentally investigated the effective role of the usages of blended cement and recently developed nylon fibers for tunnel lining concrete. It has been observed that both nylon fibers and blended cement improve the durability and physical properties of concrete.

• Tunnel and Underground Space
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• v.7 no.3
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• pp.230-237
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• 1997

As concrete structure is getting old and decrepit, its inspection and diagnosis is getting important. Therefore, it is necessary to estimate the soundness of structure using non-destructive tests for effective repairs and maintenances. But, applications of non-destructive tests in tunnel have been used restrictively, due to accessibility only from one side in tunnel lining and presence of tunnel installations. Recently, the various non-destructive techniques have been studied. Especially, ground penetrating radar(GPR) and impact echo (IE) methods have been researched for tunnel inspection. In this study, the applicability of impact echo test in tunnel lining inspection has been investigated. This paper described the tunnel inspection for lining thickness and internal flaw using impact echo tests. Model tests were carried out using impact echo test systems on two concrete models, Model I is measuring for lining thickness, Model II is detecting for internal flaw. Also, the test were applied for lining inspections in a tunnel constructed by NATM. From the results of impact echo tests, we have concluded that impact echo test is a very useful and effective technique for inspecting the concrete tunnel linings.

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.3
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• pp.97-102
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• 2002

Two dimensional Analysis has been applied to most of tunnel lining design in these days. Two dimensional analysis uses beam or curved beam element for finite element method. But because the behaviors of tunnel concrete lining structure is near to shell, it is required to model the tunnel lining as shell structure for safety design of tunnel lining structure. In this paper, two dimensional analysis by beam element and the three dimensional analysis by shell element of tunnel concrete lining are studied, in which 3 type of tunnel lining and lateral pressure factors are considered. As results of the study, three dimensional analyses of the behavior of tunnel concrete lining structure considering lateral pressure factor shows that the moment of three dimensional analysis is greater than those of two dimensional analysis. The results shows that three dimensional analysis is necessary for safety design of tunnel lining.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.5
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• pp.101-107
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• 2017

Over-break, which is excavated larger than planned line at tunnel excavation, is inevitable due to the nature of blasting. But regarding the bottom of the foundation, most of the domestic ordering organizations pay only 10 cm thick filled concrete when pouring concrete due to over-break. In accordance, the construction cost will increase greatly if all the depths of the designed over-break are filled only with concrete. When tunnel excavation occurs, concrete filling of 18 MPa(T = 100 mm) and 150 mm~237 mm auxiliary concrete layer and 240 mm concrete track(TCL) are applied to the upper part. The concrete is installed in an excessive amount of about 600 mm between the lower part of the rail and the tunnel rock bed. Therefore, in this study, it is necessary to analyze the concrete crack structure according to the depth of the existing tunnel and the modified tunnel section, and to evaluate the adequacy of the required thickness of the tunnel floor concrete for securing the crack stability of the concrete.